resistor smd 102

I recalled the idea that I took electronics seriously from the beginning. Although I was very excited, I was scared when faced with the two main obstacles faced by amateurs and even professionals: making your own PCB and fiddling less Surface mount footprint. Any resistance to the latter proved to be futile, expensive, and frankly, a bit stupid in retrospect. Cheap SMD tools make it very easy to store, place and weld all SMD items.

Once all hobbyist designs/experiments are limited to SMD, how will you produce the PCB needed for the prototype? I personally don't like to etch my own boards. This process is laborious and involves messy chemicals and particularly sensitized PCBs-I am not interested. I've only done it a few times and promised myself that I won't do it again. Professional but inexpensive PCB manufacturing is more like a board assembly service like OSH Park makes this easy and affordable-if you can wait for the turnaround.

So what are the options? If you really want to do rapid prototyping in your own laboratory, then I made a case of milling your own PCB. In the process of continuing reading, I will guide you through the typical workflow from design to prototype, and convince you to accept the relatively high start-up cost of buying a PCB factory.

In recent years, the terrible cost of purchasing CNC machines with sufficient rigidity and precision to meet the needs of the work has been greatly reduced. A quick search for "engraving CNC machine" on eBay and Aliexpress will return some interesting and affordable clicks. The general-purpose machine floating on these websites is called CNC 3020, which represents a 30cm x 20cm working area and costs about 250-300 pounds (350-400 US dollars). Other models are 3040 and 6040. These machines all seem to be based on a single design (or even a manufacturer) and are well structured. The aluminum-based structure is sturdy, and of course various materials can be processed under the correct spindle.

The cheapest machine is often equipped with a simple DC 50W electric spindle, which is reliable enough and, more importantly, cheap to replace. It is suitable for engraving and cutting wood at a moderate feed rate, nothing more. The newer machine is equipped with a 200W water-cooled spindle, which is undoubtedly a better choice. You can also use them to cut moderately thick aluminum.

I bought one of the early versions of CNC-3020 quite cheaply. The machine has no end stops, has an old parallel port-based interface, and does not install most of the PCB functions, such as automatic spindle control. We wrote articles for a while [whitequark]

 Upgrade the hardware. I also made the necessary modifications, just connect the 3 end stops to the CNC, and then weld them to the surface probe connector that was not originally installed. It is wise that many new machines are now pre-installed with these machines.

After preparing the machine, we need to obtain the correct tools for milling PCBs. The most important one is the engraving position, which is responsible for submitting all actual traces to the PCB. The bit needs to be sharp, so actually cut rather than tear the copper, and of course need to be fine enough to mill any tiny footprints or marks. After a lot of experimentation, I got the best result

. These are cheap and reliable enough for about 8-10 medium-scale jobs. However, the V profile does present a challenge when specifying its cutting width in the software, because the deeper the cut, the wider the cutting range. This can be adjusted by trial and error.

Next, we need some drill bits to drill through-hole component mounts and through-holes. Each different hole you specify requires a manual tool change, so it is best to stick to a single 0.8 mm – 1 mm drill bit, which should be suitable for most situations. I recommend buying

.

The last one we need is an end mill, which is responsible for cutting out our board from the larger PCB overlay. 1-2 mm end mills can do this job well.

In addition to the above points, we also need the actual PCB overlay. I found the universal, cheap, single-sided overlays on eBay are very bad, and they collapse like cookies when cut. The better ones seem to be two-sided, in both cases I have to try some different suppliers first

. Throughout Hackaday's history, purchasing high-quality copper cladding seems to be an unresolved topic.

In addition to the important items listed above, we also need the following:

The biggest challenge in the DIY process is to obtain the correct and consistent cutting depth. The deeper the cuts produced by these V bits, the deeper you go, effectively depriving you of precious engraving resolution. If you do not adjust the correct depth, some traces will become too thin and fragile. The key to success is to try some cutting depths, and the most important thing is to probe the PCB to compensate for any changes in the overall cladding height.

In order to adjust the correct cutting depth, I compiled a simple test design, which includes a breakout board for ultra-small size 

. The trace size on this board is as small as my design. Next, I tried several different cutting depths and finally found a cutting depth with reliable results for these fine traces. I use 0.8mm cutting depth with 0.1mm V position.

The automatic leveling process is set in the software and only includes the detection program before milling. What we need to do is to solder the scrap wire to the corner of the PCB cladding and use a lot of double-sided tape to fix it on the ideal flat scrap wood.

After completing this operation, fix the wood to the CNC work area and fix the milling cutter in the chuck. A pair of alligator clips are fixed on the wires soldered on the PCB and the milling cutter to complete the detection setup. The idea is to create a PCB height change map, if the PCB is not completely level, the rolling mill will actively compensate for the error.

The first step is to prepare the CAD files. What we need in our favorite PCB CAD software is 3 GERBER files: Top, Bottom and Drill. But before that, we need to ensure that all necessary precautions have been taken to maximize the chances of the factory copying the circuit.

As an example, let's talk about some things that I ensured when designing the following PCB that has been successfully milled many times. For anyone who is curious, this is the phase locked loop part of the DIY spectrum analyzer based on Analog Devices ADF4008 IC.

The smaller packaging used by milling in the later stages will certainly advance the functionality of the process. Since a smaller footprint also means smaller wiring, the reliability of the entire process is greatly reduced. For the same reason, I try to use 0805 or 0603 as passive components.

Compared with any professional manufacturing, these restrictions are definitely very strict, but as long as you pay a little price, you can produce practical and realistic circuit boards.

Once it is determined that all the above constraints are complied with, you need to export the GERBER files and then convert them into GCODE that can be run by CNC. To this end, we use excellent open source software:

, Specially designed for 2D PCB CAM process. It has a wide range of features, you should really check it out.

The tutorial on FlatCAM is beyond the scope of this article, please check

. In short, for each imported GERBER file, you can choose to generate various tool paths for different types of jobs, such as Cutout, Isolation milling, etc. All you have to do is to type in some parameters to specify the cutting depth and drill size.

For a single panel, we need 3 GCODE files from FlatCAM. Top layer, drilling and cutting. With these, we are almost ready to grind the board!

The final software step is to add an automatic leveling routine by post-processing the GCODE top-level file generated by FlatCAM. For this, we used another excellent software called

, which one

There are free and paid versions, and the free version lacks the ability to share detection data across sub-jobs. This is important because you can only probe the board once at the beginning of the job, that is, after you have cut off and therefore isolated part of the board from the PCB overlay, you cannot probe the drilling job! To be honest, I don’t have to buy the full version yet, because probing is only critical to the milling path.

The most important parameter in this process is the probe pitch, which determines the detection resolution. The smaller the probe spacing, the more points will be detected. Although this will take some time, it is worth at least 80-100 good results. After this file is generated, it will replace our previous "top Gcode" file, and we are ready to mill out the board!

At this time, we will provide 3 files for the single-layer board: the top file with detection, the drilling file, and finally the contour milling file. We grind the top file first. Start your favorite GCODE interpreter/CNC controller, I use MACH-3, but Linux CNC or most others are viable options.

We first reset all 3 axes, position the spindle about a few millimeters above the corner of the PCB, and then reset all 3 axes to zero. It is important not to lose the XY zero position between different jobs. Each new job requires re-zeroing on the Z axis, but the X and Y zero positions will remain unchanged. Make sure that the detection circuit is set up correctly, otherwise the milling machine will hit the PCB! Once we are engaged in this work, the mill should begin routine investigations. Once completed, the milling routine will begin, depending on your feed rate and number of passes, it usually takes a while. Once completed, despite the messy glass fiber dust, our circuit board is expected to be similar to our design.

Next, we continue to drill, this step does not require precise re-leveling. We only need to insert the drill bit and set the Z axis to zero so that the drill bit is flush with the PCB surface. After completing this step, all specified holes should be drilled in the board.

Last but not least, the board needs to be cut out from the remaining PCB overlay. The process is very similar to the previous step, but the position and feed rate are different. We zeroed the Z axis again and then run the job. If all goes well, we should have completed the PCB!

Now enter the more valuable part of the process. The milling process is not perfect, especially when the engraving head becomes blunt, it tends to tear rather than cut. To remove stray copper scraps, first scrub the PCB with a thick hard-bristled brush, and then scrub with a finer sandpaper. After wiping with alcohol at the end, we can finally weld the components!

Look at the final result. It looks good, although you can see some defects, such as residual copper traces between actual traces. Since we specified enough gaps between traces and pouring, these should not be a problem!

Now you may be wondering if this process applies to double panels? The answer is yes. Although aligning the sides may be a bit cumbersome, with the right exercises and fixtures, it is not too difficult.

In fact, FlatCAM provides a way to drill alignment holes for alignment with 2-layer designs. Finally, you may also want to know whether this well-designed workflow can produce consistent results for demanding footprints. The answer is yes. I have produced multiple boards for DFN-8 (3mm * 3mm * 8 pins!) packages at once! Check out the 1 GHz mixer based on the LTC5560 IC in DFN-8.

What does SMD have to do with it? Of course you can use the same method to create circuit boards for through-hole components!

I am kind of like someone told me that I should use SMD, just like someone told me that I should use Metric. They have many advantages and are correct in a perfect world, but they are totally opposed to other people's personal situation may be different from their own.

In my case, it will be a garage filled with through-hole parts boxes and local hardware stores. These warehouses can carry almost every type of fastener, cutting and measuring tool required by the imperial system, but if the price is too high , You can only choose a handful of options and none at all.

It is not really possible to add anything to this particular conversation. Annoying, cut it out!

The circuit board I made here is for RF mixers> 1GHz. Try to do this with THT. In principle, enjoy the ease of THT as much as I can, but limit yourself, which prevents you from doing many things, such as RF.

IMO smd is much easier than THT, no need to constantly flip the board

As long as all your components are on one side...

Not only that, insert the component, flip the board, solder, cut the wire, flip again and repeat. Patching is much easier. Just place and solder, no need to cut lines and flip the board. Double-sided board does not matter, every side is fine.

Flip chip-welding bottom component-flip chip-welding top component.

Flip twice.

I only flipped twice. I pulled all the through-hole components to one side of the board and bend them to fix them while inserting the axial wires. Turn over the solder of all components on the board, trim the legs and finish. But I also do SMD for high density boards.

Ask you to accept:

Indeed, the main function of through-hole components that cannot be achieved in RF is ampere: all other functions are no big deal, because they are already quite lossy in nature. It's just more expensive.

Lol. Therefore, people have given reasons to use surface mount. I will repeat.

"They have many advantages and they are right in a perfect world, but they totally disagree that other people's personal situation may be different from their own."

So... I will not try a through-hole construction> 1GHz. So? But this does not want me to throw away a box of through-hole components and buy all new SMD products. Hmm...unless I find out that all the products I build are> 1GHz. I don't think this will happen, but at the same time, I have no reason to waste it.

However, for me, the more important point is:. I can perform CNC machining on a board, whether it is surface mount or through hole mount. So, why does an article about etching a board on a CNC controller even have to start a meaningless argument?

Why are you so angry?

It may be because you can paste breadboards on through-hole components, but not on SMDs (without breakout boards), so the main obstacle to using components provided only in SMD packages is the inability to quickly assemble prototype circuits. So... this is the way to solve this problem without having to deal with annoying chemicals*.

*Except for inhaled dust that can cause cancer

If we compare the workflows, then the feeling of people inserting through-hole components into a solderless breadboard will not replace the step of "using the breadboard out of the box and stealing the circuit board" for designing and manufacturing a prototype PCB. Moved by the convenience brought. A few jumpers, and then put them on the table. "

If you are sure that the circuit you are designing is a product, it will be beneficial to start with SMD, especially if you want to implement another standard and do not need to build a proof of concept first. But I think most people have not built their own circuits. Maybe it will eventually become a product, but it may not.

The complaint is not that someone is using SMD, but that many of them then turn to people who use THT and tell us that we did something wrong. It's not.

SMD nonsense is just that; meaningless parades serve as information. What I like the most is my opinion; what you like the most is not my opinion, just nonsense.

The actual theme of this story is not about SMD vs THT, but about using a mill to make PCBs. For people who use THT, it is as useful as people who perform SMD. After all, they did make SMD prototype boards, and SMD people actually didn't need to design PCBs to achieve this goal.

The only "about" and "about" in the story are "milling", "etching" and "ordering".

*I use emacs for programming and vim for system management, which is why I am an expert.

If you want to use double-sided overlays for through-hole machining, you need to mill both sides. As the article points out, it is feasible, but it adds a lot of pain and complexity. Therefore, SMD is much easier, and you can use the other side for the RF ground plane. :)

If single-sided copper is used, through holes are easy. But you cannot get SMD density.

In my garage, most of the boxes filled with through-holes disappeared because almost all manufacturing processes were handed over to SMD. Of course, there is still something that needs to be used/through holes, but it almost disappears. In the past, you could pick up a lot of extras through the holes in the hamfests, but now it's mainly SMD reels.

Not to mention that the complete E24 resistor/capacitor classification can be placed in a box of 20cmx30cmx2cm.

"You are milling on both sides. As the article points out, it is feasible, but it brings a lot of pain and complexity."

So... I guess you created a double-sided board but no vias, so each side looks like its own isolated single-layer PCB? After adding vias, you need good top/bottom alignment, which is the same as using a via plate.

As for the ground plane, even if every project I have ever worked on involves radio frequency, I can still use the old through-hole power supply to build power supplies, control boards, and any other products that do not require a ground plane.

If I want to compete with portable commercial products in size and weight, SMD density really matters. My things are probably disposable items that I live at home or in the car.

"You used to be able to pick up a lot of extras through holes through hamfests, but now it's mainly SMD reels."

Wow. We will never participate in the same carnival! In my area, they are still through-hole materials. This is how I originally used a garage full of it!

"In my garage, most of the boxes filled with through holes disappeared because almost all manufacturing processes have been transferred to SMD"

My garage is more like a playground for hobbyists than part of manufacturing.

"Not to mention packing a complete E24 resistor/capacitor classification into a 20cmx30cmx2cm box."

good idea. But... all the salvaged mechanical parts really make my workshop messy. Although my components may take up more space than you, eliminating them will not really reduce costs.

good idea. I have a corner dedicated to components, and the rest of the mess is dead equipment (most of which are salvageable annual sales discoveries)

It seems that there are some good arguments for SMD in RF applications. It's kind of like metrics with some good arguments. Perhaps the complaint really stands out in a useful and constructive conversation?

Most amateurs need to be able to use metric and standard units. So someone tells you that a person did a mistake by leaning on a windmill.

Then someone said: "Oh my God, I don't like complaining, how dare you complain about others!" In my opinion, this is not consistent. The original complaint was not complaining about existence, but about other people's choices, and the response was complaining that the specific complaint made ("this should be metric") was inappropriate and impatient. Then, the third person said: "Maybe the complaining speech really annoys people." They didn't even realize that they didn't address what other people complained about, talked about different topics and didn't do anything. There is no substantive meaning at all.

Maybe you are right, but maybe you are wrong, so maybe you should flesh out your ideas and check their consistency?

Island routers are slow (for example, the equipment we purchased takes 3 to 5 hours per side), but they are useful for certain types of problems.

For example, ultra-thick high-power switch boards or tuned RF cables.

However, if there is no through-hole plated through-hole, it does not actually provide any other functions except the classic chemical etching process.

There was a time when the CNC process was used to deburr the RF wire, but most high-speed rolling mills usually add more potpourri than they remove.

I recommend using Chilipeppr or bCNC on the automatic leveler. Both can be automatically leveled, but they are free and well integrated.

+1

And check the woodpecker CNC controller.

If you are using Windows, openCNCpilot is a simple gcode transmitter with automatic level of grbl. There is no web interface like chilipeppr. bcnc is very good.

I am using mach3, but I lost the steps due to a problem on the parallel port card. Running arduino grgr on the parallel port input on the 3020 cnc runs more smoothly and reliably. It allows me to use usb. I use the same toolchain written by the author, such as eagle –> pcb-gcode –> autolevel –> mach3 –> cnc. Grbl has different detection methods, so the tool chain is now eagle –> pcb2gcode –> openCNCpilot (with built-in automatic level) –> Grbl –> CNC

hoo! I really like using these cheap CNC milling machines for PCB!

Buy used 1/32" end mills from eBay

They are so cheap that they won't even sweat to throw them away when they become dull.

I think that by using an end mill, you do not need to perform any automatic leveling. Moreover, you can use the same tools for trace cuts, circuit board outlines and drilling.

Make sure you buy FR-1/Bakelite board, not fiberglass. I just got it directly from Bantam

I used 2 inches wide double-sided crepe paper tape to press

. I think it is easier to flatten than plastic double-sided tape.

We have been using CNCJS to drive GRBL arduino to connect to the factory

I hope more people start to do this. Super fun!

Good tip, thanks

I have achieved great success in these areas

0.5mm end mill, two packages, very cheap

I agree to use an end mill for engraving and drilling. I did the opposite of the author. I drill first, then engrave.

However, even with an end mill, the result of leveling with AutoLeveler using a leveling instrument is better than "digging in", which just finds the higher part and over-engraves one area to ensure that the other area is engraved correctly. I did some retests on the board to compensate for the uneven copper cladding.

First drill a good hint, thank you!

Is there any benefit to drilling first?

I grind first. My drilling tips: 0.8mm drills sometimes move around (and when the cemented carbide then breaks;)), but the remaining 2-3mm fractured cemented carbide drills work well and no longer drift, thus forming very Clean hole. (Some of my milling can be seen in the YT link here: hackaday.io/project/24926-arduino-driven-led-display-with-bt-data-transfer)

Greetings

Is the hobbyist market so big, or is this small shop a one-off?

If your market is large, the time it takes can be prohibitive. In this case, this only applies to prototypes, and you will send the product to the production board.

Unfortunately, the CNC 3020 link (not the hackaday article link, but the link contained in the articel) is closed...

AliExpress/eBay is full of these 3020 (or larger/or smaller-numbers are size) machines. Just search for "CNC 3020".

The problem is that the machine usually has a curved main shaft, the main shaft has a large runout, and the shaft will bend under load -> poor results. Look for a variant where the main shaft is driven by a belt and is located in a suitable bearing.

Many of them also need some simple modifications to make it work with modern computers without classic parallel ports (electronic devices are just a few power transistors controlled through the parallel port, bringing all the negative effects).

The detection circuits required for leveling are also additional parts (not difficult) that you must build, such as sacrificial plates and parts that actually clamp the workpiece. The fixtures provided by some suppliers are generally unusable.

Therefore, you buy a machine that costs $800, but expect to make a lot of modifications before it can be used for this type of work.

I personally don’t think it makes much sense to mill this type of board-it requires a lot of preparation, the milling itself is slow, noisy (not good if you live in a flat apartment!) and very dusty (you need a vacuum cleaner) to remove Dust, do not grind FR4->Dust can cause cancer! ).

If I use conventional toner transfer or photolithography to complete the milling of the board, then I will have completed the same work and completed the assembly work-in the latter case, the resolution is also cheaper than these The milling machine can achieve better. The only problem is to drill holes in the through-hole parts, but a decent drill stand is much cheaper than a CNC milling machine, and there are very few holes in typical surface mount boards.

Like some microwave designs, milling requires precise surface dimensions. But for the general prototype? why? ? Some people are afraid to worry about chemical reactions, but of course I prefer to deal with things like ferric chloride instead of factory noise and dust, especially in apartments.

Oh, don’t forget, today you can get ten 100x100mm circuit boards for $2 in a week-two layers, solder mask, plated through holes, screen printing, and wiring in any shape you want. Then why should I polish it? I only make my own boards for the various adapters/branches I need now, otherwise it doesn't make sense.

***This is a special price of JLPCB, but even the normal US$20 is pretty good, especially considering the fast turnaround time.

See my comment below, the $230 all includes Pi (connected to the mill via USB) and limit switch.

When you do small SMD with small pitch, the milling effect is very good. I always try to etch away the traces and wait for completion elsewhere.

I agree that sending it out is a multiple method. But these are very useful for prototyping. Verify the design to avoid delays in Asian development boards. Yes, they are noisy, but like you, I can take out a plank, including drilling holes in less than 20 minutes. And I don’t have to explain to my spouse the small amount and disposal of chemical substances. Different tools can accomplish the same job. To everyone himself.

Although I would not use this setting on the PCB, I found this inspiration. I'm thinking about keyboard keycaps.

A small frame can place several keycaps flat on the side or side (for engraving on the front). Depending on the size and shape of the drill, you can even change the width of the font by deliberately changing the drilling depth. Fill the grooves with paint and/or resin to achieve a lasting effect.

I bought a similar factory at MicroCenter for about $200. It has a controller based on the woodpecker GRBL. There is no end stop switch, but it took several hours to reach the end.

I added Pi Zero W, which is completely independent of chillipeper. You can even drag and drop Eagle files directly on it, and it will spit out wooden boards.

Great tutorial. I used Bantam CNC (formerly known as Othermill) for this, which was originally designed and made the software easier. But considering that companies like OSHPark can manufacture PCBs for as little as $1 in a few days, I don't do much milling anymore. Why not just use OSHPark and get a double-sided circuit board with through holes in a few clicks, which is really difficult to do in the factory?

>However, given that companies like OSHPark can manufacture PCBs for as little as $1 in a few days, I don't do much milling anymore.

I never understand why people think that the price of OSHPark is so low, when it is not. The price of a two-layer board is $5 per square inch, plus shipping. Usually, transportation is the main cost...JLCPCB is the cheapest price I know, 10cm x 10cm is 2 dollars, but transportation is not free, and the top cost is about 10 dollars.

OSHpark 2-layer boards cost $5 per square inch, but you can get three of them. Therefore, the effective cost is $1.66 per square inch. Free shipping from OSHpark using regular post. Yes, if you want to speed up production and pay for faster delivery costs, you can do so, but it is not required.

Recently, I have been using dirtypcbs.com, and you can buy a standard 2-layer PCB at a price of US$10 x 10 cm (~10 copies) for only US$17, plus a Hong Kong Airlines shipping fee of US$9. According to my experience, there are several weeks. Compared with OSHpark, the price of four or more layers is not expensive. Therefore, the price of ten boards is 26 US dollars, and the area of ​​each board is about 4 square meters.

> Free shipping from OSHpark using regular post.

Only if you live in the United States (especially people who live in the United States tend to forget) in the United States, most people on the planet will not do this.

Dirtypcbs is a terrible service; low quality planks and slow shipping. However, even if you seek high-quality services with reasonably fast shipping (it only takes a few days worldwide), it will not damage your bank...

OSHpark is ok. For people living in the United States, it is undoubtedly one of the best choices in the local area, and the price is relatively cheap. Take Europe as an example. Although there must be very good and expensive PCB manufacturers, there are actually not so many *reasonable price PCB manufacturers.

Just correct this here: we (OSHPark) have free international postal mail shipping for most of the 4 years.

Hey, I am glad to hear that.

Again, OSH Park has saved me countless hours of frustration-when I sent you the Gerber files produced by KiCad, I got exactly what I expected, and for me, it was worth the wait. I am actually like a purple solder mask. Apart from our enthusiasts, no one even knows what it means to see a purple board-everyone else says: "Oh, pretty".

Is there an ulp or other simple way to make gcode burn paint from the gerber file? Most of the things I found are used to isolate routing.

The Gerber format was developed to drive the Gerber photoelectric plotter. It is basically a 2D CNC machine, so it is basically a list of XY movements. I think it is a very simple matter to convert each line in the Gerber file into one or several lines of G code. It does use "holes" for the pads, so there is no need to specify a path for each individual pad, but again, each hole translates into many discrete movements. But no, I don't have the name of any software that performs this operation. I think the simpler and perhaps faster way is to generate a raster file (.png format), you can use several programs (I use gerbv for final verification, and do this), and etch it as a picture.

Since you are talking about ulp, I assume you are using Eagle. I just asked Eagle to export the bitmap (BMP) at the resolution of my laser cutter (500 x 500 dpi-full spectrum laser), and then only used the Laser program to rasterize the bitmap. The traces are not as good as those obtained by grinding or photoresist. Enough for 15 million traces and spacing, but don't try to use 0.5mm spacing SMD for this operation-at least I did not succeed. If anyone else has achieved greater success, please leave a comment and let us know.

As you have to wait three, four or more weeks to reach the board of directors, this dispels people's mood and destroys the concentration of the development cycle. .Shipping from OSHPark to all over the world is not so fast (and not so cheap)

+1 I like OSH Park, Seeed (for white mask, no code) and other suppliers for making beautiful wooden boards, and I like the milling that I want to complete the project today.

You can buy a lot of express delivery for $300...

Since most Chinese express freight rates have fallen to around US$50, this is a good thing for the couple.

I have tried this method, not just laser engraving PCB, but so far, the easiest method I found is to spray bare copper, use the laser to ablate the paint only where it needs to be etched, and then use hydrochloric acid Mix it with hydrogen peroxide (you must pay attention to the mixing ratio), and then wipe it with MEK after etching to remove the remaining paint. It is possible to use a router, but I found that the cheaper machines are cumbersome and the installation time is longer than just using laser and acid etching.

To try the laser method at home:

What power laser do you use?

What is your minimum trace width?

Does the paint type matter?

I am also interested in it. This sounds like the easiest way. I don't have a laser cutting machine, but if it doesn't require much power (for example, more than 5 watts), you can place a laser module on my CNC engraving machine, which is very useful. All other methods have many ways to solve these problems.

In my opinion, it all depends on the density and size of the traces or the overall complexity of the circuit board. I can see milling simple boards, but I don't think it will be great to mill complex boards. I also agree that it will be more difficult to process double-sided boards with a mill. One reason is that photoetching has been around for so long.

I can't see that the registration of the second side in the mill is much more difficult than the registration of photolithography. This is indeed the least difficult.

Does the through hole in this design have a purpose?

I originally thought they were fenced vias, but they have not yet been connected to the (presumed) bottom ground plane.

In fact, these may be fenced through holes. If you choose to plate through holes, you can keep these through holes, which are preferred in the milled version shown here.

Can anyone calculate the cost of a 100mm x 100mm board, including all consumables (engraving machine drill bits), just for comparison with outsourcing? I saw the 20-minute figure, just to compare the cost of using this and the cost.

Apart from being able to iterate faster, I don't see any monetary advantage.

If you have time, please waste it, if you want to be faster, please do it yourself :)

I recently converted my old Ordbot Hadron 3D printer to a PCB board, and I am not excited about the best stitch length I can make. Now, I want to perform a mixture of drilling and milling first, and then toner transfer and etching. We will see how it works.

For the actual PCB, I usually order from OSH Park. Because when I need something quick and dirty, I often use perfume. And since less than 10 cents per 5×7 perforated board is not cheap enough for me, I often take apart eh Dremel and cut off the unused parts for later use.

"Each 5×7 perforated board is less than 10 cents"...Unless you need a spacing of less than 2.54mm, it will either become very expensive (I found that the cheapest price for a 1.27mm perforated board is a small piece of 10 U.S. dollars), or completely impossible. I have never found such a perforated board, it can meet TSOP components (most large-capacity RAM chips need) pitch 0.8mm or QFP (most modern programmable logic devices, such as CPLD or FPGA required pitch) 0.5mm spacing. . You can* try to use a breakout board, but the signal may not work well in the gigahertz range of hundreds of megahertz or lower.

I tried FlatCAM, it is difficult to run under OSX. I used Carbide3D's network tools to play a lot, and its quality left a deep impression on people. In addition to the unexpected "zero offset" in the generated GCode, it also works perfectly.

It's nice to read the article about this technology. I started to work on the entire design/printing/etching method, but I was tired of all the etching steps and personal contradictions.

Now, if I need to do something, I can do the layout, print it out on plain paper, and then tie it to some copper cladding with a dremel with a cut-off wheel to cut the traces. It's not pretty, but it works. The smallest component I need is SOT23-6, so it is not small enough that I need more detailed wiring.

I have never liked milling to satisfy the hobby of PCBs, because it is a hobby in itself. As mentioned above, they are getting better and better. It is under hacking, so you can conduct electronic hacking.

I stay away from photoresist to meet the needs of amateur printed circuit boards, because it has become a complete hobby in itself, and progress seems to have stalled. It is under hacking, so you can conduct electronic hacking.

I bought an inkjet printer for PCB only. It is certain that it has been seen by HAD for a long time. The special anti-corrosion cartridge can work and needs improvement, but it can work. It's almost here... just failed.

At this level, we have been stagnant for many years, but the progress made here and there for such examples is very interesting.

I'm still using a laser printer for transmission, and for small quick things, I need to make a sharpener by hand. There are still some datak plugins that work properly, they will corrupt themselves, but they will get old.

Maybe you can drag several garbage laser printers together and build a double-sided laser scanner to directly expose the pre-coated photoresist plate... But again, another hobby that can be developed on its own.

Thirty years ago, we believed that we were on the verge of some new hobby toys that could solve this problem for us. Many people like this are okay, but, guys...we have been trapped in sand and spinning wheels. Some people have proposed to get rich, but time is running out and things have become so small.

The most needed part of the hobby is more than 20 years old. Nothing can be resolved yet. Almost, but no ringtones.

Until someone creates a home chip technology factory...just like Jeri Ellsworth tried to do.

Rinse/repeat ha ha, hope th can be realized soon

"Until someone creates a home chip technology factory"-until?

Describes a manufacturing system that can be used to produce 200nm-scale semiconductors on 4-inch wafers using a desktop device, while the manufacturing cost of the desktop device is less than $400.

Julian: I haven't walked through the paywall, but the $400 seems to cover only the UV illuminator needed to expose the photoresist. This is just the simplest of the many equipment required to actually produce the chip. You need to be able to produce a mask and reduce it to the actual chip size, and copy the pattern of each layer at precise intervals. You need something to align the mask so that the layers can be perfectly aligned (in Tens of nanometers), you need to be able to spin-coat the wafer with photoresist, you need to use a furnace to diffuse the dopant into the crystal lattice, you need to score the wafer and then break it into chips, and you need a Method Bonding wires to pads on the chip and then bonding to the lead frame or PCB. About fifteen years ago, this is what I learned from the loose connection with the manufacturing process (I did laser trimming and test development, so it was processed when I got the wafer).

Jeri Ellesworth (Jeri Ellesworth) proved by making a huge MOSFET that the real wafer processing steps are achievable for enthusiasts, but this is at the level of masking with tape. Not at the level of chips used in production.

Again, this may become a hobby, and it will be a good choice for hobby communities like CNC machining and 3D printing, but I think the whole process does not exist yet. Someone please prove me wrong.

Now that I have read what I wrote, there are actually not many devices. Among them, the wafer scoring step may be completed by a hobby-level CNC engraving machine. And someone outside may figure out how to do wire bonding. This is also within the accuracy of amateur CNC equipment. Mask alignment? Don't know which one. I know that by combining a mechanical stepper and galvanometer with a computer vision system (video microscope and pattern recognition software), you can reduce to the 1 micron range, but even this is not suitable for the faint-hearted.

Hi Biomed, I have a 102% consensus with you on this point – it’s fun to try something non-stereotypical, such as making a PCB with an engraving machine, like trying to make a resist layer with a laser printer, and like trying Using a pen plotter is as fun as using a fine-pointed Sharpie pen to draw circuits. Even trying to use "professional" methods to make masks, sensitize the plates, expose and develop them, etc., all have a good size learning curve. However, when I try to do other things (such as building a circuit), these things are no longer interesting. I am the opposite of ADHD. I hate having to change the task on the fly, because when I return to the original task, I have lost any thoughts in progress.

The method described above is the method described by Cody, which uses paint peeled off with a laser cutter, which sounds like the easiest to correct-I have never encountered troublesome etching parts. The question has always been how to obtain a resist pattern on copper.

I feel very lucky because KiCad has reached the level of development comparable to the professional systems used in the past, and now provides services such as Seeed Studio, DirtyPCB and OSH Park, so I don’t have to be confused. I have not developed a reliable process. The K-child. In my last three projects that required PCBs, I went to OSH Park, and in all cases, I got my design completely. In other words, any problems I encounter are design problems, not PCB fab problems. It took nearly two weeks to get the board, but it was because I spent two weeks doing other things instead of two weeks, and wasted a lot of materials trying to make the process work properly.

Great article, thank you. I have some small questions:

\ cite {I use a 0.1mm V-drill with a cutting depth of 0.8mm. }-Is this a typo or is it really cut by nearly a millimeter? There are many methods. Depending on the cutter head, 0.1-0.2mm (I use a 45° engraving cutter head) is enough to cut through the copper wire reliably (also depends on the stiffness of the Z axis).

The cardboard cutting board on your picture looks terrible-is the cutting knife dull? When cutting FR4 boards with a simple 2 or 4 edge milling cutter head, I got clean cutting edges.

Many Chinese factories are offering 10 pieces of 100mm x 100mm or less circuit boards with green solder masks priced at $5. 2 layers, double-sided screen printing and solder mask. With the DHL Shenzhen shipping fee of about US$17, I can reliably get the board within 7 or 8 working days from the start of the order. The circuit board in each hand is about $2.20.

For schools that "but I can never use too many boards", for some reason they *must* buy 10 boards, even if their out-of-pocket costs are lower than buying fewer boards from other sources, they still feel torn, you You can also order 5 yuan for the same price of 5 yuan. Hehe, how is this saved? You save transportation costs.

I have printed Cyclone PCB Factory and it is very close to milling my first board. However, I was having trouble centering the chuck on the spindle. Looks like yours, two hex nuts. The adjustment is very sensitive and I always feel a little swayed. The video here is bad:

.

Is there a tip?

These spindles are notorious for being eccentric. My condition was good at first, but as the bearings/bearings wear out, it gets worse. The spindle seems to be malfunctioning.

I have done it all: CNC milling PCB and chemical etching. I don't understand why people claim that you have to deal with "nasty chemicals"? Ferric chloride is very safe and can even be used for water treatment. If it enters the environment, it's no big deal. It does stain your clothes and many other things, but I used it when I was a kid with chemical devices. Even the photoresist developer is quite safe, and sodium hydroxide is a waste. Sodium carbonate is heated baking soda (yes, it can be found in food). Don't think they are "nasty" and try it. Both methods have advantages and disadvantages. When I need to drill holes for through-holes or many through-holes, if very fine pitch is required, I use cnc milling bars. Oh, to answer other people’s questions, you have to drill before milling because you want to prevent the drill from moving.

I have read that ground PCBs can cause lung cancer because if tiny particles are released in the air. Does any of you consider it?

Where did you read it? ? ?

Well, where did you read it-are there any details? First, how about allergic dermatitis? If you are worried about dust, please try wet grinding?

It is dangerous to drill or grind (or mill) glass fiber here. One solution is to use paper/phenolic paperboard (FR-1 or FR-2).

In any case, these should be enough for side projects. I found that even the cheapest circuit board manufacturers, you can't beat their quality. Isolation routing is suitable for testing and prototyping to confirm whether the design is correct. But in the end it makes you want.

Bart, yes... Some kind of vacuum/filter system that sucks in particles during the grinding process would be very good-not only good for health, but also reducing the "wood dust" manually vacuumed after the cutting process. Although I really like PCB milling. If the user has the appropriate system (software, hardware, measurement/alignment/adjustment/setting method), this particular technique is certainly feasible. For the home environment, it is definitely better than handling chemicals. But...in any case... it works for each of us... Very good and, as always, safety is important.... Therefore, it is best to wear masks and goggles, and consider how to set up the system to avoid health problems.

If you have sharper tools and proper settings, you don't have to sand your planks, don't sand for high-speed steel, and don't go for cemented carbide. Unless you plan to cut hundreds of plates, they will not wear out, and they can increase the feed speed without heating and cracking. Heat is your worst enemy to keep your tools sharp during machining.

Now, as long as you have the right tools, you should use a very high rpm, preferably 30000 or higher.

Then keep the feed speed at 50-100 mm/min.

Keep the depth around -0.2 to 0.3 mm. If you go deeper, the track will be wider, and the shallower will be burrs.

Soak the boards with oil. This must be used: First, it keeps the tip of the knife cool, thereby keeping it sharp and avoiding burrs.

Second, it will absorb all the dust, so you don't need to use a vacuum cleaner or your lungs to suck it up, just wipe it when you are done. As an added benefit, it can also suppress noise because it can reduce vibration.

It took me several hours of thinking and testing to reach this conclusion, but it was worth it. When typing this command, there is a cheap $200 CNC on the right side of the keyboard, which is running the PCB. I don't even have to watch it at runtime, just play the game and read it at the same time. I will never use acid to make PCB:s anymore, which is time-consuming and laborious.

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The first thing to learn in electronics is how to recognize the value of a resistor. Through-hole resistors have color codes and are usually where beginners start. But why mark them like this? Just like the red stop sign and yellow line are in the middle of the road, it actually seems to have always been this way.

Before the 1920s, manufacturers marked parts in any old way, just as manufacturers liked to mark them. Then in 1924, 50 radio manufacturers in Chicago formed a trading group. The idea is to share patents among members. The name changed almost immediately from "Associated Radio Manufacturers" to "Radio Manufacturers Association" or RMA. In the past few years, there will be more name changes, until it eventually becomes EIA or Electronic Industry Alliance. EIA actually no longer exists. It exploded into several specific parts, but this is another story.

This is a story about how the ribbon enters every through-hole resistor from every manufacturer in the world.

By the late 1920s, RMA developed standards, one of which was the RMA standard for color coding. The problem is that marking small parts is difficult, especially in the 1920s.

The solution is ribbon, but it is not as we know it today. The color standard is the same, but the main body of the resistor is the first frequency band. Then there will be another two or three bands showing the remaining values. In some cases, the third band is actually a point. Therefore, most of the resistors will be the first ribbon. The "tip" of the resistance will be the second frequency band, and the dot will be the multiplier. Radios using this scheme began to appear in 1930. This is the color code table in the 1941 Radio Today Yearbook:

Be careful with the advertisements in the magazine promoting resistors, they are RMA color coded. The code quickly expanded to capacitors (capacitors in modern terms).

Depending on the position of the resistor, this point may be hidden like the printed text on the cylinder. So in the end, everyone turned to the band.

The color should follow the visible spectrum (remember ROY G BIV?). However, RMA omits indigo because it is obvious that many people do not distinguish blue, indigo and purple into three different colors;

, Obviously. There are four slots left, so dark color represents the low end (black and brown) and bright color represents the high end (grey and white).

Of course, if you are color-blind, none of this is funny. Reading a resistor with a meter or bridge from the circuit is undoubtedly an answer. However, reading one in the circuit is another matter.

In 1952, the International Electrotechnical Commission (IEC, another standards organization) defined the E series, which specified the value of resistance input so that the spacing on the logarithmic scale of the resistance was equal. If this sounds confusing, consider an example.

The E12 series is suitable for 10% resistors, and its value provides you with 12 values ​​every ten years. Basic value

This is why you can get a 4.7 K or 47 K resistor instead of a 40 K resistor.

However, please consider the tolerance. A 10% 39K resistor may disconnect 3.9K. If the error pushes the resistance higher, it is 42.9 K, so the 40 K resistor is not needed. In other words, in any case, a 39 K resistor is likely to be a 40 K resistor. On the other hand, the low 47K resistance may be 42.3 K, which is less than the high value of 39 K units.

As you might expect, when the tolerance decreases, the number of values ​​increases. For example, in the case of 2%, you will use E48, which has 48 values ​​per decade (if you guessed E96, the 1% standard uses 96 values, and you are correct). Using E48, the values ​​close to 40 K are 38.3 K and 40.2K. It is 39.06 on the high end and 39.2 on the low end.

Next time you pick up a resistor and read the code from it, you can review the history behind it. The remnants of the ribbon will continue to the surface mount area, not as a color, but as a multiplier representing the three-digit number of the first two numbers and the resistance value. Nowadays, many electronic devices (such as wireless modules and lithium batteries) contain a data matrix (similar to a QR code). To be honest, it surprised me that there is no microdata matrix of some kind on all components (through hole and surface mount) that allows you to point your phone at them and view their complete data sheet. Maybe one day.

Wow, the body color + belt + dot is a real improvement to the current beige plus color, it can be any scheme.

It always seems ridiculous that we label them, so, given that 10% of the male population is frankly color blind (red-green), more people have subtle shifts or simple color discrimination. Isn’t electronics the territory of mankind?

Then, I realized that in fact this kind of work has quickly become female dominance (and as far as I know, this kind of work continues to exist in the sweatshops of the Far East). – I may actually view these statistics. Women are far better than men in this subtle detail-oriented technique, and genetically speaking, they are more likely to suffer from color blindness and have to be more careful.

I will put my hands here. I use a cheap DMM to test the resistance and write it into the resistance bar. I know the color and how the marking should work, but frankly, whether it is black, brown or green (especially the cheap small resistors I ended up buying) is hard to be sure.

I also suffer from color blindness. The biggest trouble is between brown and red. I have to check with an electric meter every time. However, I found that if I take a picture with a digital camera and zoom in, I can distinguish the colors. Maybe my camera (unintentionally) changed the color, or maybe it's because of a larger sample?

I think it is difficult for everyone to find brown and red on old parts. Similarly, white can become yellow, yellow is pale enough, you want to know if it is dull white, and blue and purple can fade so much, you want to know if they are gray.

This one. There is no consistency between manufacturers, and if there is a value issue (making the color code meaningless), I usually find it easier to just use DMM. About time it gets updated. One person’s brown may be another’s orange, and so on. Hopefully, the next step will be to interpret haha's clear transistor labels without the need for an electron microscope.

^ THAT ^ and the color change that occurs when the resistor is overheated!

B ^)

If the resistor overheats, its value will also change. It is best to take the correct value from the schematic (if possible).

Ah, that 0 ohm 0% resistor.

When repairing the power supply, I found that many power supplies have accidentally installed 110 ohm 1% resistors.

You don't need expensive 0R 1% resistors, you can use cheap 0R 20% types :-)

I think that it is more common than color blindness that many cheap and efficient light bulbs produce poor color rendering. Normally, orange and red will look brown. In some cases, it is difficult for me to distinguish purple from blue or black.

Sorry, I forgot to include "Many people don't distinguish between blue, indigo and purple".

The shocking answer to this is that this defect is clearly psychological to a large extent (especially because of the transparency of the lens, people have subtle color cast defects).

But just as the painter or the people you spend all day around the swatches seem to have the superpower of color discrimination, so do the people whose language is clearly distinguished in color by name.

Native Russian speakers are faster than English speakers in distinguishing light blue from dark blue (goluboy or goluboy in Russian).

[reference

with

It is precisely because the words in Russian are so different (tested by people who learn and speak Russian, better than people who have never learned Russian). Wow.

There is no indigo in the Russian rainbow. Instead, it is "light blue, blue, purple".

This seems a bit strange, because I would say that cyan precedes blue, and it is not "light" but green.

Well, cyan ("blue") is somewhere between green and blue ("indigo"). Before entering the computer, I have never heard the word Cyan, here is "turquoise", Americans call it "teal". Therefore, it is no wonder that it is not widely used. Yes, it is green, but I think if you shift the sample further to blue, it will look less green and more light blue. In any case, this is a language problem. Obviously, it is difficult for Eskimos to distinguish certain colors visually because there is no word in their language. It's really not surprising, I bet they have a lot to say about "white people".

The language/visual connection is real. Without a word, you usually don't distinguish colors well. According to Stephen Frye (QI) about QI, the ancient Greeks did not have the word "blue", for them the sky was "bronze". However, whether it is true or false, it is a QI fact of about 50:50. Generally speaking, the same applies to most things that technologist Stephen Fry said.

"Cyan" has been used in photography for more than 50 years and is part of the subtractive color triplet "cyan, yellow, magenta".

In printing, it may also be the most famous. Including consumer printers. However, most people are still not printers or professional photographers. In addition to making their own color film, do photographers need to use these colors in large quantities? Photography uses the RGB color model, which is the output of modern camera sensors. Even internally, they use more innovative colors in the color filters.

A young man named John Savard / Quadibloc owns the most interesting personal website of mental bric-a-brac. He is a very smart person. He has a page about filters used by the camera, not just Bayer, but also his own suggestions. You can use other colors to let more light through, then mathematically find the color of the pixel from each of the three sensors, and perform some addition and subtraction operations. Letting more light in almost always means higher quality and accuracy. Of course, the exposure time can be made shorter and the noise is also less.

Blue-green is blue-green, and blue-green is blue-green.

Only color-blind Americans call cyan blue-green "blue-green", because ordinary people only regard blue-green or "blue" or "green" as a category, so they don't have to worry about being so specific between similar colors.

Teal is not common among artists outside the United States, but any American who can see colors knows cyan and cyan. But they still call it "blue" or "green" most of the time.

Blue-green is only a greener one than cyan. When I set the grayscale on a color TV, I will start by establishing cyan. There is a sweet spot in the middle between blue and green. Once the requirements are met, red will be brought up to create white.

Too much, it looks brown, although some people do like to turn red, if the audience who raises the color control on their scene has the right to vote. I personally prefer "flattering" answers to borrow Hi-Fi terminology.

Why is it cyan? If I guessed it, it seems to me a quirk. But this is something you don't mind watching, because the most difficult part of the TV image, the skin tones of various people and the woods (tables, walls, cabinets) all look like they should be. If I can take advantage of this quirk, my customers will be happy. Yes, I do have a photography background.

However, as I grow older, I am now facing presbyopia. This will affect my ability to look at work. If I want to see the tiny details, I prefer the +3.25 card reader. What a pity, because I was able to solder SMD ICs with my naked eyes. Not so much anymore. At least night vision and color sensitivity.

Fun fact-In Welsh, the same word is used to denote the color of grass and sky.

The ancient Greeks called the sky "bronze"

Is it just me, or do other people have problems when distinguishing the color code that the resistor body is some strange brown or green color? But also noticed that compared with male colleagues, female technicians and engineers have less trouble distinguishing colors.

With SMT things, this has become meaningless.

I think this part is related to color blindness, which is more common among men. And it is more common in the red and green parts of the spectrum (brown has a lot of red).

From my experience, it seems that women see more colors than men because I have been tested for color blindness and it is normal, but it is difficult for me to distinguish shades of pink. The color is usually called salmon, peach, pulp...

There are many good things for color vision on the second X chromosome. I am color blind and I absolutely despise the old color coded long resistors. the worst. Can't we stop doing this and just print small text on them as we do with all other types of components now?

I assembled a small object, which includes a disposable multimeter and two Y-shaped brackets made of wires. I can put a resistor into it and read its value quickly. Of course, it has no effect on reading the value of a resistor that is already part of the circuit. I mean, one in ten men is color-blind, and even more people have difficulty coloring even without a generalized disease-how did this marking scheme pass? Or at least why does it still pass? This is not the seventies anymore, we can print out detailed details on these things.

They also chose the absolute worst color for the beige background and the most used bands. They are really addicted to brown, green, red, orange, yellow and other junk colors, which are the most laborious colors in deuteron eyes.

They can print beautiful details on things, but can you read it? SMD resistors are flat and rectangular, usually larger than through-hole resistors. Stripes are definitely more suitable for small cylinders. There are also printing costs, which must be very cheap for the profit of resistors. Small exquisite printers may be beyond their management capabilities. The printing on the SMD is shaking enough.

What I see with one eye is a little blue, but the other eye sees more red. Therefore, one eye may be a little red, while the other eye lacks blue. Both eyes have (I think) the correct color.

Maybe you are developing cataracts! Otherwise, as you age, your lenses will turn yellow. There is a famous artist who I have forgotten. As he grew up, he suffered similar pain. Compared with when he was young, experts have studied his paintings, which have a completely different palette from when he was old. Together with experts, they analyzed the colors and accurately matched some age-related color degradation. The painting from the middle shows the progress between states, even along the correct time scale.

Do not!

He just forgot to take off his 3D glasses!

To be sure, there is almost no difference between the normal color vision of men and women.

Some women are tetrachromatic and can provide better color vision, but this is certainly not the norm.

However, in addition to the common red/green, there are other forms of reduced color vision.

Wow! I don't know that some people are four-color, so I did a web search.

Explains the concept that men can only see in primary colors :-)

What exactly is "purple"? ?

Therefore, 10% of men are colorblind (most of them are dichromatic, such as 0.1% of women), and theoretically 15% are tetrachromatic (0% of men).

There are considerable differences imo

But as far as I know, in any of my research from color change to a thorough and better distinction between women, there has never been a visual difference between men and women. Some of it may be the psychology I described above.

"Another study showed that up to 50% of women and 8% of men may have four pigments and the corresponding increase in chromatic aberration compared with trichromatic mirrors."

Yes, I found out that I had this problem a few years ago. The solution is to ensure that my entire workshop is equipped with fluorescent lamps. Incandescent lighting will only make the problem worse.

Due to the toxicity of marking dyes, many modern SMD resistors leave the factory without marking at all. Switching to other types of bulbs will not help, you must be organized.

…true? First of all, I have heard of it. Don't think that ink is highly toxic in the field of electronic components. Organizing is a good idea.

Most SMD components are applied by machines, and they don't have to bother trying to read them. Through holes are still used by hobbyists and prototyping staff because they can be used with breadboards.

No one tells you, shouldn't you eat electronic parts? :-) But even if you do, the two most common white pigments, titanium dioxide or zinc oxide, are non-toxic. I think it is even classified as a food additive. Only lead-based pigments should be avoided.

I think this is just a cost factor for printing on small 0402 or even smaller components. Resistors in 0603 and higher are still marked.

In Australia, I have seen many foreign tourists asking how to tell which snakes are poisonous.

I just told them I didn't know because I don't eat snakes.

That may just be part of your luck. Usually the cause of the problem is fluorescent lighting, because the peak spectrum may have a tilt aligned with the color band, making orange or red look brown, etc.

High-wattage incandescent lamps (not dim, light yellow 40w bulbs, etc.) will have "perfect" color rendering, so they are actually the best choice for distinguishing colors.

A high-quality fluorescent lamp or LED is almost as good, so if your fluorescent lamp has a good uniform spectrum, or has a peak in the right position without causing any interference, you are good, but if you want to Choose a lighting fixture workbench and read the many color codes, it is best to try any lights you plan to use before submitting to them.

What I want to say is that only sunlight (6000K) can have perfect colors. Unfortunately, incandescent bulbs are limited by the melting point of tungsten. Therefore, for some rooms, I prefer to use 6000K LEDs. Although the color rendering of some rooms is really poor, you must choose a good room with a high CRI.

LED mainly adjusts the color temperature by changing the amount of blue light in a very narrow frequency band-therefore, it is a low CRI light with lower blue light. It does not help you see colors, because the iris of the eye mainly responds to blue light, so by having a strong peak, the eye restricts the amount of light entering the retina, causing the other side to lose color contrast. Because of the Purkinje effect (Purkinje effect) at the end of the spectrum (red becomes black).

Ironically, due to its nature, cos incandescent lamps have a full spectrum. Although they may lack the power of blue, their light is usually yellowish. The solution to this problem may be to throw more photons and fluorescent lights are brighter, although yes, cool white lights also have more blue.

The color temperature of the halogen bulb is slightly higher.

When the light level drops, the sensitivity of the eyes to red wavelengths decreases and blue increases. When the natural color temperature starts to shift to red, we react to seeing the color "correctly" under sunset conditions.

I don't think it is necessarily color blind (@zé) or lighting (@Medix). Those cheap resistors with almost lime green are really scary. I think the paint they used for the stripes was a bit too transparent, or maybe it was applied when the body paint was still wet, so it was mixed. Either way, the colors will be mixed and become something that only people with extensive mixing palette experience can read.

Lime green! I have seen light blue, but most resistors are official "salmon". I think the 11th color must be found, not to be confused with the other 10 colors too much, and they have used gold and silver, it must be a challenge! It would have been easier to genetically transform more cone cells into engineers.

Okay, not exactly lemon green, a little darker, but this is the closest shade I want to talk about. I received them when I bought very cheap items from Ebay sellers in China. I also saw them being soldered to the PCB of consumer electronics. They are really hard to read, and I often have to use an electric meter. I hate to do this, because then I don't know if this is the actual expected resistance or out of specification. Will the latter be stable? It is best to only buy new ones. Although you don't want to wait a month or more, it is becoming increasingly difficult to do so now.

When working on art, my color discrimination is above average, but I often look at a resistor obliquely under bright light. It is different from the colors used by other manufacturers and lies between the two colors. Their bad colors made me question my vision.

I hesitated and said: "Well, it's nearly 5% more than this color, so it must be this color!"

I try to remember that before squinting too much, the DMM can reach and is faster.

I'm not a color-blind person, but I agree that the color codes of modern resistors are harder to read than those of the 60s, which have a dark brown body and opaque color stripes.

Cataracts and age-induced retinal dystrophy can also cause loss of color vision. Especially in the first case, as people get older, everyone’s lenses will become a bit foggy, which can cause a drop in contrast and saturated color perception-the brain is used to it, so you don’t notice until it really deteriorates.

I believe Bill will not talk about his memory of resistors for more than 50 years.

You can compare old resistors in old equipment with modern equipment to understand the difference Bill said.

I am dealing with many old-fashioned technologies, and I can confirm his words.

Thank you for confirming that this is true. I don’t like to do this when people are skeptical of random guesses such as those mentioned above, which indicate that serious health problems are the cause (or other human “defects”). Luke's answer was (probably unintentionally) a rather hostile reaction.

This is a general reaction, indirectly indicating that the "observer"/human being is always at fault (due to imperfection) and defending the problematic technology/solution/method.

A mentality that is too common among various technicians.

I don't think a person will be hostile unconsciously. Maybe not sensitive. Although on the other hand, they can also be paranoid, spiny and overly sensitive.

If you are using a resistor 50 years ago, it is not unreasonable to assume that it is 50 years ago. There are many grocery stores here! This may not be the case for you, but guesses based on forum posts are acceptable guesses. You can refute it freely, just like in the past.

Everyone’s eyesight is declining. Especially those who spend a lot of time looking at the screen while the rest is staring at tiny colored stripes. Therefore, this is not an unreasonable assumption.

Again, you can refute. It's ok. Don't feel sad, that guy doesn't know you. This is just a suggestion based on part of the information in the forum posts. For many people who cannot see the colors of modern resistors, this is their age! Belongs to the best of us. Wait until your eyes start to spin, and then you will find gray hair everywhere on your head and body!

Strangely, when I was middle-aged, my eyes lost some flexibility. The optician said it was normal. But in this way, I can now read better without glasses, including computers. I am cured! Unless there are far away places, I still need them. Therefore, when I mess up my phone or read something, I tend to stare at them like a clever guide, and then push them back into my nose when I actually see them. In front of the computer, I just took them off. Put them on the table. They are there!

Making assumptions about health is never a good thing.

My eyesight gradually weakened, and I could barely see even with glasses.

My lung function dropped to 52%. I was diagnosed with COPD and I was looking forward to spending a short life in a wheelchair because my lung function gradually declined so that I could not support my vital organs.

Now, my lung function has reached 98%. A recent eye exam showed that my vision is better than the average vision of my peers, and there are no people wearing glasses.

I found that my condition was the result of toxin exposure, not related to age. I left the environment where the toxin was.

Never think that health begins with age, otherwise you may be left behind and fall into a debilitating state that does not require pain.

It is indeed difficult for me to distinguish certain colors, but not always.

Stupid aging eyes;}

I did not consider how the color of the resistor body might change, I must pay attention next time.

But even if it doesn't, my red/orange will mix, and my brown/purple will mix.

Just the night before, I had a 5-band resistor, and I swear that the gold band was always yellow, and then cursed my eyes again until I noticed that the 4th band was purple.

The brown-black-black-purple "gold" will be 1 billion ohms, which (useless) makes no sense.

It is strange to realize that I knew the correct color at one time and read silly things backwards. That is 1% 470.

There is indeed a gigaohm resistor. Usually, they are not color-coded, but I am pretty sure I have seen at least one color with normal "stripes".

I have done a lot of work in audio equipment electronics and condenser microphone preamplifiers. Very high resistance resistors are common. Sometimes as much as ten megohms.

The resistance of the grease left on the finger may be less than 10 megohms.

Next step-what is the range of 0 ohm 5% resistance?

I do have some zero ohm resistors. Of course, a single black belt lacks tolerance information.

But your comments did make me want to draw my own silver or gold bands at the end and somehow try to get them back into the wild.

Can you imagine the look on that person's face ten years from now? >:}

Once upon a time, I ordered a roll of 1206 zero ohm resistors, and Digikey sent me a roll of 1206 fuses. I realized that I can't say that they gave me the wrong part, it's just not the part I ordered.

According to my experience, the range is about 5 meters.

The joke is that when you look at the data sheet for zero ohm resistors, many times they do specify tolerances.

The product code of this resistor is RC0603FR-070RL, where RC0603 is the size, F is ±1%, R is the reel type, 07 is the reel size, 0R is zero ohms, and the last L represents a custom label. When ordering these parts, if needed, you can technically order a resistance with a zero ohm resistance of 5%. Anyone will guess what you will get.

Ima buys cheap Volt or Leaf batteries. The battery has been burned out and equipped with a zero-ohm resistance container with a tolerance of 5%. It is tested to find out the resistance of less than 5% ohm, and then the car Drive away and sell the rest of the back.

*Starting from 0 ohms, derp, should be obvious from the context, but for nitpickers...

If you bought it from eBay, then 5% of the time will be a 0.4 ohm resistor.

@RW: 5% of zero is still zero.

Also, please don't forget that some of them have very high TK, up to 4380ppm/K.

But for most "zero-ohm jumpers", they do not specify a tolerance, but a maximum value. Value, for example 50 milliohms.

The "maximum" is also strange. A manufacturer provides a 200V 0R jumper in the case of the "working voltage" specification, which will be huge power.

Oh, I know they exist, but I have never bought or used anything myself, so it doesn't make sense to put them in my parts box.

Of course, the parts bin may resemble a garbage drawer. I found someone there somehow only surprised me a little.

1 Gohm, what glass are they made of?

Never understand why smd capacitors have no code for resistance

This is because the assembling robot does not query the physical map like we do. Compared with girls who do more complex jobs, they are paid higher.

I guess this is because SMD parts are directional, there is an "up" part that can identify troublesome parts from any angle, and these parts have no codes, and the space on the parts is not too small.

There is no "left" or "right" for through-hole resistors. Or think about it "upward". You can determine the end that starts with gold/silver/no streaks at one end. The same thing can work like a cylinder on a rectangle.

Don't fucking tempt them! Their actual numbers are much better than those bad, useless colors! They should modify these numbers in turn and place them on the resistors.

useless. Until you use low TC parts printed with that value, but the machine that loads them puts all the values ​​on the PCB. The schematic is not helpful, because the code is under the part. Read the documentation carefully until you find the board layout, then cross-reference the schematic and know the value after 5 minutes, and you can continue troubleshooting-if you remember why the value is needed.

I also don't think SMD resistors should be installed in reverse. The resistive element is usually on the top, so if it is mounted on a board, the maximum dissipation may be worse.

do not know! I always thought they were a mixture of various solids such as carbon and binder. interesting!

No, they are usually mostly solid mixtures of aluminum and oxygen. Usually called Al2O3 ceramics. With a thin layer of metallic glass resistive glue.

In the Soviet Union, the denominator of resistance is represented by numbers

The link is broken or forbidden:-(

Just press ENTER in the URL line.

Unfortunately, it is not used today.

!

When I was very young, I learned how to read basic resistor color codes and never looked back. Of course, when I need a strange value in the parts kit, I still need to find something, but this is a value that has never been used before. I do admit that I first noticed this strangeness in a pamphlet about standards published by Radio Shack a few years ago.

Interesting article-thanks! But I am still confused about the concept of E series and tolerance. I have heard two explanations:

1. The most common situation is that 10% of the resistance is random, and the error may be as high as 10%. For example, due to the manufacturing process I think, a 100 ohm resistance may be between 90 and 110 ohms. However, I have never been able to find relevant basic statistics. Does this mean that the resistor has an average value of 100, a standard deviation of 10, and a Gaussian distribution? Or, the distribution can be uniform between 90 and 110 ohms? If anyone has a good reference, I would appreciate it.

2. The "non-random" interpretation of the E series is that if the design requires resistance R, the nominal value is always within 10% of the required R value, and with a 10% resistor, the designer will never exceed the required sum The error between the nominal resistance values ​​is 10%. Does this mean that resistance randomness is not assumed? (That is, the actual R value is very close to the nominal value, otherwise there are two sources of error, namely the difference between the actual value and the nominal value and the randomness of the actual R value). Maybe a 10% 100 ohm resistor actually has a small standard deviation, maybe one ohm or less?

Any clarification would be great! If you are not an electronics expert, if this falls into the category of "stupid question", I have to apologize in advance!

There is also a third version:

3. The manufacturer measures and produces the same batch of resistors in batches. First, they remove 1% of the resistors, then 2% of the resistors, then 5%, and then 10%, and then discard the remaining resistors or sell them to night brands outside of China Retailer.

This means that the resistance of 10% will almost never be lower than 5% of the actual value, unless the factory issues an order to transfer part of the 5% or better bin to the 10% bin. In other words, unless you buy a 1% resistor or a 0.1% resistor, you will never get close to the actual value.

Good article, still really don't know why the band is needed in the first place. The new resistors illustrate their value, and the resistor is only replaced once about once, and the only time if it has burned out and the strap is not visible. If you want to clone the circuit, remove the part so that the trace can be seen. I think this might be useful for recycling, but I can't imagine that resistor manufacturers would want to help. Are they more useful when the cost of dmm is higher than the battery that comes with it?

I remember that I once found a resistor for laboratory use in a class. They use some 1/8w small resistors that have been in use for more than 20 years. Even with a microscope, it is impossible to distinguish yellow to brown and orange to gold. The lecturer didn't even know what they were, so he only gave 100% to everyone. Very useful stuff!

Well, the working performance of these belts is much better than that of cylindrical parts.

But none of your arguments are about ribbons, they are just against any form of labeling.

I guess that once the circuit is put into use, you no longer have to quote the part label, which gives you even greater motivation! (Completely a pun), but I am glad they are there.

If you consider older chips with nicks, it is more of a color issue. But now imagine this problem, even the poor engraving effect will only appear in the 360-degree rotation of your head!

Well, I often use old gears from Germany and Russia, and there is no problem with resistors playing their value in "plain text". But I must admit that I also know some color codes.

In the right way; this part may not need marking. We live in a world where half of the chips obtained on the board do not have a usable data sheet, and even many discreet components lack any kind of identification. I know the cost of these wire gauges is not high, but I also know that resistors are very cheap, so can I save a lot of money? If nothing else, please consider the school wasted hours on this... Get rid of the mark, these courses become useful things!

In my case, I usually buy the cheapest resistor that best suits my requirements. Sometimes they have blue bodies, and these lines make me unable to read or even new. Don't care at all, it's actually like looking at it from a visual appeal point of view. The minimum price per 100 units is reduced by $0.01, which is the part I want to buy, even if it is not marked.

Or, this may be a somewhat strange idea, and the manufacturing may like...provide each resistance value in several different colors. In this way, if your product may have 3 through-hole resistors, you can buy red, green and blue resistors, it is more difficult to use the wrong resistor, and it is easier to check the resistor used! Industrial machine vision cameras are expensive, and there is a big price difference between a camera that can check the correct skin tone and a camera that can read the ribbon. Unlike we see hundreds of through-hole resistors on modern boards... Generally, if you use them, they are only used for some high current projects.

Have you ever encountered a 30 ohm resistor, it obviously decided to have its own little rebellion, and can withstand greater resistance until it reads 330 ohm? This is the reason why the VCR does not work properly because it is in the circuit at the end of the IR LED of the tape detector.

Yes, but once you take them out of your school bag, they are practically useless! Of course, you will use a multimeter, but the striped ones are independent of any type of measurement required.

In terms of their Gaussian distribution, I think you will get "random" as in "random". unknown. This is the point. Therefore, you do not know the exact value of this one or any of the other hundred. It means that what it says is nothing more. Even if there is some known random distribution in the manufacturing process, how do you guarantee that they are boxed? Random is random, no more information!

I used to have a cheap DMM blowing a resistor.

According to the schematic, it needs about 111.1 ohms.

(I have the schematic because I built it with the Vellemann (?) kit.)

I checked the resistance with a reliable digital multimeter, found an equivalent resistance and soldered it!

This is an interesting idea. But I want to know whether it's not a big deal to prove that by making various series?

If the target value moves only slightly, 10% of one person may be 1% of another.

I guess the change from the scheme you described to the better scheme I made is to reduce the proportion of more resistors produced and sold in various series, making it easier to make low tolerance settings

The distribution of value largely depends on the manufacturer. Back in the bad age of carbon composite resistors (belonging to the Allen-Bradley category), a good carbon composite material manufacturer could almost control the quality of the entire batch of products at 5% or more even if they were labeled at the factory. Good level. 10% is sold as such. If trucks are parked by the lake for a day, they may absorb enough moisture to reduce the value of the moisture below the tolerance limit, so they must be baked to restore specifications.

Carbon film resistors are better and can be rubbed to high precision before coating. The same is true for metal films and cermets and any common technology today. Many modern trimmings are done with lasers instead of abrasion. If the manufacturer does not waste it, there is no excuse for a batch of 10% resistors without resistance within 5%.

There are other questions. Resistance has a temperature coefficient, and its value will drift with age. If a resistor must handle power close to its rated power, it will age faster. If you really need 1% resistors, you don’t want to buy resistors using technology that can produce cheaper 10% resistors and meet the specifications.

These choices are not entirely correct.

Resistance is set by material characteristics and size, both of which need to be controlled during the manufacturing process. The chemical reactions are relatively easy to keep consistent-volume and mass measurements have been well understood for centuries, and some laborious measurements have been used to make a large number of components. The formation of physical resistors is difficult to accomplish consistently, requires measurement and adjustment of each part (very expensive), or expects that the part is allowed to miss the target with a certain allowable tolerance. That will infer the Gaussian distribution.

Over time, the costs associated with this process dropped sharply. Early resistors may have tolerances of 20%, but the automation of manufacturing has allowed tighter tolerances to be achieved at ever-decreasing costs. However, when you want to manufacture 100,000 pcbs and 100 resistors, the price difference of each resistor is 1 cent, which is $100,000, so in most cases, parts with looser tolerances are a better choice.

When selecting this series, the given tolerance should be considered. It is almost certain that the measured resistance is closer to its specified resistance than the next value in the range (next direction). that's it. If you choose a 47K 10% resistor, it may be 42.3K to 51.7K. The next value (39K) in E12 can be 35.1K to 42.9K, and the next value (56K) can be 51.4K to 61.6K. Even at the 10% tolerance limit, if I want 47K resistance, I will most likely choose 47K. Now consider whether the tolerance is 20%, but still choose from E12. The range of 47K is from 37.6K to 56.6K. The overlap of 39K (31.2K to 46.8K) and 56K (44.8K to 67.2K) is very important-if I want a 47K resistor, any of the three values ​​can be provided. The measured resistance of the resistor marked 39K may be higher than the resistance marked 47K, and the measured resistance of the resistor marked 56K is less than the resistance marked 47K. In other words, it doesn't make sense to use the E12 range to select a resistance with a 20% tolerance, because it will not give you more certain values ​​than selecting from the E6 range. Similarly, for a tolerance of 10%, it is almost meaningless to choose from the E24 range, because it gives you less certainty than the E12 range. and many more…

Even if the process control is improved and the variance is reduced, the tolerance value is still only a guarantee. Although 47K 10% resistors manufactured today are more likely to measure 47K than resistors made 50 years ago, the outlier may still be 42.3K. In mass production, guarantee matters are very important. For most circuit designs, resistance values ​​outside the guaranteed range are disputed. Unless absolutely necessary, good circuit design does not require components to meet strict requirements, such as high-end analog electronic equipment (such as professional audio) or test and measurement equipment.

There are some techniques that can rely on the above techniques. Suppose I have a small part to sell in three versions, one is a normal specification, a value specification and a super high-end specification, and the design relies on the critical 50K resistor to some extent. I can simultaneously use 10% of the components in the E12 series to achieve all 3 specifications. First, I designed the circuit to distribute 50K resistors to multiple components. Normal specifications are connected in series to get 47K and 330 ohms. I relied on modern strict variance to create the specified 50.3K resistance. In the quality assurance process, the resistance and the product performance produced by it have passed the specification verification. The budget version has looser product specifications, which can be met by 99.9% of the components, and solves exceptionally serious abnormalities through a warranty plan. The super-spec model replaces a 300 Ohm resistor with a 470 Ohm trimmer potentiometer, which can be factory and after-sales calibration.

I'm pretty sure that your plan to use multiple components will not help, and will actually make the situation worse. If you are not lucky enough to buy a small part with all resistances at the low end of its range, the final accuracy will be even lower. On average, I don’t think there will be any difference. But in general, this will cause additional problems that cannot be solved.

In addition, you mean 3.3K, but we all know it.

Yes, I mean 3k3. Fart at the end of a long post.

Compared with one resistor, the purchase and installation cost of two resistors will not bring any additional problems. The distribution of two additive Gaussian distributions is itself Gaussian. Add the mean and variance.

However, there is no 50k resistor in E12. Not in E24 either. Even E48. Therefore, when choosing a "50K" resistor, would you choose a 47K average distribution or a 50.3k average distribution doubled the variance?

This is easy to visualize in R:

x = seq(40,56, length = 500)

plot(x, dnorm(x, mean = 47, sd = sqrt(2)), type = "l", lwd = 2, col = "blue", main ='normal distribution', xlim = c(40, 60), ylim = c(0,0.5), xlab ='R', ylab ='φμ,σ²(X)')

curve(dnorm(x, mean = 50.3, sd = 2), add = TRUE, type = "l", lwd = 2, col = "red")

The E24 series (usually 5%) allows you to reach 51k. Even there-two 5% resistors with a total resistance of 50.3k are a better choice:

plot(x, dnorm(x, mean = 51, sd = 1), type = "l", lwd = 2, col = "blue", main ='Normal Distribution', xlim = c (40, 60), ylim = c(0,0.5), xlab ='R', ylab ='φμ,σ²(X)')

curve(dnorm(x, mean = 50.3, sd = 1.41), add = TRUE, type = "l", lwd = 2, col = "red")

You must go to E96 to get 49.9k, but this is still not strict enough to meet the over-spec requirements you want to calibrate.

I did a rough Digigikey search on 1/8W through through-hole resistors (because after all this topic is about color codes). It is almost impossible to buy a 10% resistor today. So...Stackpole 1/8W 5% resistor is $0.00589, similar Vishay Dale 1% resistor is $0.0675.

If you build 100,000 small parts, the cost of using a single 1% resistor and two 5% resistors is $5572. If that can meet the market demand for small parts, it will be a very respected design choice.

In fact, my example is artificially designed, and given that there are many better options today, in their correct thinking, no one would choose a 10% tolerance for "some critical" components, let alone critical components . Horowitz and Hill will be shocked. What matters is not just tolerances, but also other attributes such as temperature coefficient and humidity resistance. In my defense, I did not say yes, but only said yes. The value selection in each resistance series can be traced back to the days when you might use a 10% tolerance. Even so, the trick is still valid, but today you will choose two 1% resistors so that the average value is close to the nominal value available only in E192. The comments on eevblog indicate that the difference in resistors is usually much better than expected. From their tolerance specifications.

Similarly, "the given tolerance should be considered when selecting this series. It is almost certain that the measured resistance is closer to its specified resistance than the next value in the range (next direction)."

I think this is for the manufacturer's sake. This means they can bin all resistors, regardless of their resistance value, almost every resistor they make will be within 10% of the resistance value of one or the other. As others have said, resistors within 1% are sold at a price of 1%, but with a tolerance of 10%, almost every resistor will have a place.

Logically speaking, those with a tolerance of 20% will be almost completely between the other values. Assume that everything that falls within 10% is removed and sold with better tolerances.

Chip resistors are sampled in batches and are not individually boxed. Due to the variation of NiCr thickness and the accuracy of the optical and motion control systems aimed at the laser used to trim them, there is still a normal distribution within each batch. In turn, these will depend on the life of the machine. Older machines, newer machines have better initial specifications, and the machines will wear out over time, reducing their performance. My view is that it is usually more advantageous to replace the production line with newer equipment and introduce a new product line with better specifications than trying to pick cherries in batches from an older production line. As a result, the older tolerances eventually become obsolete.

An example-Vishay TNPU chip resistors have a tolerance of +/- 0.02% and a temperature coefficient of 5ppm/C. Older product lines with larger 1% tolerances cannot achieve this goal. It is worth noting that high-precision chip resistors are usually thin-film NiCr, not thick-film. I guess that the film thickness is the control variable and the main reason for the increased tolerance.

Precision wirewound resistors are usually measured individually. For decades, their manufacturing process has not changed much. The process variables include iron core (diameter and cylindricity), welding wire (diameter, cylindricity and tension), and mechanical accuracy of spot welding and winding processes. Most of these are easy to control and can be mass-produced with high precision. However, the spool can only be wound with one resistor at a time. The resulting high production cost reduces the cost of a single measurement.

In all these areas, it is important to remember that good circuit design does not require strict tolerances unless necessary, and even today, this is much less. Few people now use discrete components to build A/D converters, so buying ICs is usually more effective. Wheatstone bridge? I know. Audio preamplifier? I know. The analog system has been replaced by the digital system. Bipolar transistor with MOSFET. Discrete resistors have mostly been downgraded to support roles, such as pull-ups and protections, and strict tolerances are not required in these applications. I would not be shocked if more 5% tolerance chip resistors with 102 and 103 values ​​are used than the sum of any other tolerance values.

I'm not sure about the resistors, but choosing 1% surface mount capacitors for 0.05% tolerance applications, it took a puzzling time. (They will be used at low temperatures and it is impossible to obtain more precise components.) Their distribution is definitely not Gaussian. In a batch, you will get about half closely clustered around some very specific values ​​and a bunch of outliers. The next batch will have a very different center value. We didn't bother to record those records that did not meet the specifications, but my qualitative impression is that a certain peak value is different from the calibration value by a fixed value. This is a huge peak with wide tails in both directions.

Similarly, they first select parts with higher tolerances from the lot.

It is basically a Gaussian distribution, because the process is not completely accurate, it will be biased to one side, and then the bell curve is divided into two according to the nominal value, and then all the parts with the highest accuracy are taken out to different warehouses .

If the cluster you measure is higher than the nominal value, then it should have a tail to the right, if it is lower than the nominal value, then it should have a tail to the left.

What I didn't get was that almost every introductory e-book stated the color code of the resistor at the beginning. But almost no one mentioned how to interpret the capacitor marking! Of course, in most cases, electrolysis is obvious, but not many disc capacitors.

As a child, I grew up before parts were cheap and ordered online, and the lack of any markings on most inductors was a strong limiting factor for my budding electronics hobby. I dream of reusing parts from garbage equipment, but most of them I can’t determine their value!

And it doesn't work. At the time, the L/C table was not an option for children's budget. Now everything is cheap!

Ceramic capacitors use the same system as SMD resistors... but the values ​​given are expressed in picofarads.

104⇒10 0000pF⇒100nF

473⇒47 000pF => 47nF

331⇒33 0 pF⇒330pF

Of course, with the help of the Internet, it is not difficult to find these days. But when resistor color codes are almost everywhere, why is this information not included in more of the initial electronic text?

Because it is difficult to write this part clearly, you can read it from the beginning before purchasing the book.

the same.

For years, I have been searching for information on how to read these old resistors and capacitors. At last!

Can't you find the color code of the resistor? In fact, it is given in every introductory electronic text. There is still no rhyme we are going to mention here... I am really surprised, "How to find a resistance value" or something in the Internet search must be resolved soon! Or, you just need to ask an electronic freak. I think your expectations are higher than expectations!

Stuart, I think this is problematic because the microfarad mentioned in the 1940s guide above. But then I noticed that it was distributed in two lines, not a typo... it said "Pico Farah". Didn't they have ancient Greeks in the 1940s? I think they just don't have an ISO standard!

Do not. This is not what we are talking about here at all! How did you read so much from the comments without knowing the content of the article?

What is not in these books is how to read old, vintage resistors, where the color code is not stripes. Even if you know the colors, when they are the main color, the base color and the dots, in what order do you read them? This is not the usual left-to-right streak.

When was the last time you saw the opening electronic text containing this information? I might doubt you, because you only read very old texts on electronic products, but I might want to know that micro-microelectronics is not old news for you.

I'm thinking, today someone's thinking is a few thousand times slower, right?

"Didn't they have ancient Greeks in the 1940s?"

Before learning electronics, I had never met a person who had studied ancient Greek or consulted ancient Greek.

I even read "Anabasis".

You know Mega, Wei, Wei Wei. I speak that kind of Greek! "Pico Farad", like they did not invent other scale words, even though they have capacitors that need them. Not entirely serious.

Yes, this is the case in terms of reading OLD resistance. Who knows what my brain is doing?

"Before I studied electronics, I had never met a person who had studied ancient Greek or consulted ancient Greek."

Have you seen such a married person?

Some analog meters have a capacitance range. Connect the capacitor in series with the meter and connect the 115 VAC 60 cycle power supply.

It will be your trouble to build your own clear bridge for capacitors, resistors and inductors. Using some known good components as references, you can even have calibrated measurement equipment.

I rarely use capacitors that can withstand 115VAC, and the actual power supply voltage (230V) is much less. Therefore, low-voltage methods are essential.

OMG, thank you Al!

I have a few humidors filled with humidors that look like the "Résistancesanciennes annees 50.jpg" picture. I am not sure if they are resistors or inductors, nor how to read their color codes. All I know is the band!

I think inductors older than that will have visible windings. Wire wound resistors may be like this! I really don't use those museum works in the actual tour. I want to measure their actual resistance with meters if needed. I think if they have drifted over the years, they will not drift anymore, but in fact, you can spend a lot of money to buy a humidor equipped with modern resistors. Maybe you can sell a few old records to someone who restores antique radios at once. Again, I don't want to rely on old components for anything connected to the mains. Even if my antique radio is still usable, I would not plug it in without supervision.

Although they are not useful for some museums, their value or rarity is not enough to be useful for museums. Take them as an example, you can show them as well as modern resistors and SMDs to show how they shrink over the years. It is interesting that we still use the same color code itself. You can keep them and hope they become valuable before your grandson dies. Or after a certain future end of the world, no one can get any more parts. You built a 2-way radio and you are known as a hero in the community. In addition, despite this... I would not use them because they are too rare, but there are as many as they are because they are definitely useless and unreliable.

"Maybe you can sell some old records to someone who restores antique radios at once."

What do you think of the day I bought them?

Everything I've read shows that the resistors in antique radios usually do. It is best to replace the capacitor. So.. If my radio does have a burnt-out resistor, it may be the result of a damaged lid that cannot be closed, then one of these resistors is likely to be a good resistor that was properly replaced on schedule.

If it has drifted a lot, I would not use it. I am afraid to believe it. Now that I know how to read their marks, I can finally test them! If they are available or useless.. I will determine eventually.

Nevertheless, although I admire and like to watch antique electronic products, I still spend more time on modern products. I only really own an antique radio, and I want to restore a day’s family heirloom. Even if repairing antique radios becomes my new main hobby, I might use these resistors for life, with a lifespan of 3 days.

They may be very suitable for circuit sculpture. They are more decorative than any modern decoration. Or maybe it's because a small QRP rig without a casing was made. Here comes the mites of Michigan.

"I will not let it be inserted unsupervised." "

How to install an appropriate size fuse in the device?

Yes, but some parts of the radio may become so hot that the power supplied through the fuse may be dangerous. Some parts should at least get hot. They sometimes use only resistors to lower the supply voltage. At that time they used cloth insulation and wax, and the safety standards are not now. I would really doubt anything old. It's not that you can't enjoy using it, but maybe don't put it on the shelf next to a bottle of methylated alcohol, but stay in the room to listen while plugged in.

I might also want to assemble a short-range AM transmitter and play some music from the 1940s/50s through it. Now listening to the radio trash through virtual antiques will annoy me!

A (possibly) interesting side note: an early radio manufacturer (Philco?) installed new lighting equipment, possibly mercury vapor lamps. The increased light level is welcome, but it makes certain colors indistinguishable.

Their solution is to have the engineer change some resistor values ​​to colors with fewer problems!

Nowadays, the same problem: The CRI of LED lighting is poor, and it is especially difficult to distinguish red: red, orange, gold, and brown are beginning to be similar to each other.

I also found this problem, so I installed a bunch of 95 CRI natural white LED strips (designated as 5000K, measured at 4900K) above the workbench, and now the color reproduction is very good.

There is only a 40-watt halogen lamp on my workbench. CRI = 100

40W halogen lamps do not have that much light output. I prefer 40-50W fluorescent lamps or LED lamps.

Although a few years ago, I still needed a short-term solution to overnight SMD assembly. The 300W or 500W halogen lamp achieves this purpose very well, except for its high heat output-it has been in early summer, dripping sweat will not act as a flux :-)

For spotlights, enough.

I think it depends on the phosphor. A single yellow phosphor, together with the blue LED on which they are based, will emit a "white" light, but I don't want to use it to light up my house. In particular, it is not necessary to identify the color under it. Again, although I will use a multimeter as much as possible.

If they add extra phosphors, they can get better light. The name from the appropriate manufacturer comes with an English or European name, at least a name with Latin letters (!) designated for lighting, which may be better for CRI. Put in some red, green and other phosphors to get the widest possible frequency band. The LED is monochromatic. Like every Ebay supplier that sells goods, cheap, nameless Ebay LEDs are purely price-based, and you can search for prices. Price-quality = profit, so quality is the enemy!

Many people have noticed that this may be a problem, but don't know why. The public's ignorance and boredom leads to one of the things that are shy. It's like politics!

The "better" CRI> 80 you can find in any supermarket without special order. They basically just add red phosphor to the yellow phosphor. It is difficult to find bulbs with CRI>90 anywhere, because 80 bulbs are a cheap manufacturing point for these products, and most consumers will not notice or care.

But this is still bad. Even if the CRI of the old compact fluorescent tube is> 87, and to have good color rendering, you want to be greater than 92.

When I discovered that our assemblers used 270K (red, violet, yellow) and 4K7 (yellow, violet, red) resistors interchangeably, I had to do something similar. The 270K resistor has an arbitrary RC time constant, so we switch to the adjacent value (220K or 330K). Close enough!

An older colleague of mine believes that E3 values ​​of 1, 2.2 and 4.7 are sufficient for most components :-)

It does feel that most of the old resistors on the earth are beginning to appear brown-black, red-red or yellow-purple. If I had to guess, the next most common value will start in blue-gray.

Using only those E3 values ​​in the gain circuit R/r, you can approximate the gains that are important in log10 mathematics-1, 2, and 5. Using the E3 series of only 30 years, that is, 9 total values, you can get about 0.01, 0.02, 0.05, 0.1, 0.2, 0.5, 1, 2, 5, 10, 20, 50, 100, 200, 500.

The combination of two E3s in series (or an E3 with a 0 ohm jumper) can generate: 1, 2.2, 3.2, 4.4, 4.7, 5.4, 5.7, 6.9 and 9.4, which is a good starting point in the linear range. Adding the value of 6.8 can also generate 7.8 and 9.0.

Please correct your article, this is "Résistancesanciennes annees 50 by François Collard, CC-BY-SA 4.0".

When my grandfather passed away, I learned that he was in "resistance" and passed the British pilots from one place to another, through the forest.

Resistance is not in vain. Oh, sweet!

I like the simple three-letter system used for SMD parts, but the "new" EIA-96 is indeed PITA. I will never remember these things, always have to look for it. Measuring SMDs online is not always feasible, and sticking them in a confined space and removing them without damage will not be fun.

In any case, all this will soon disappear. Resistor manufacturing has started to stop printing values ​​on SMT resistors.

Mainly a few

#1) They can save $0.0000000002 and save ink cost by skipping the printing process.

#2) There is no value on the capacitor, and no one complains, so why do we do this to the resistor.

#3) The machine mainly installs them and does not need to read the value.

In the next few years, you will pay high prices for marked resistors.

#4. In any case, 01005 size SMD cannot be read.

First of all, I think they cannot be handled.

Among the many resistor manufacturers I deal with every day, none of them plan to delete the mark (due to the work of electronic contract manufacturers, I think there are at least 9)

1) The cost has nothing to do with the added value of the mark used for inspection and other post-processing. The resistor material is ideal for adding a marking step, so this is the reason for the standard process for resistors.

2) Due to material reasons, the cap is not marked. Labeling capacitors with standard methods will not lead to very obvious results. Manufacturers can use laser-based processes to obtain caps, but this adds considerable cost and is therefore not standard.

3) The perfection of the machine is only human-loaded machines and traceability tools used by manufacturers. After SMT, flying probe or ICT style tests are not always used to verify the assembly, and when a 10k resistor is loaded instead of a 20k resistor, the functional test cannot always capture, but it will affect the end user. Using AOI, AXI and visual inspection are more cost-effective solutions for quality management.

4) Yes, for 01005 and most 0201s, legibility is limited.

Can a typical AOI recognize the printed content on the resistor? Or is it not possible because ICT is more reliable?

The mnemonic-it is best to be right, otherwise your grand plan will go wrong-(black, brown, red, etc.-purple stands for purple) has helped many learners. Of course, there are also hard-shell variants, but this "clean" version is suitable for hybrid companies!

Bad beer rotten our young courage, but vodka is going well

Hey, Elliott!

What is the German who put the rose on the grave?

Oh, I do not know. I have to ask around.

Dutch: Zij Bracht Rozen Op Gerrits Graf Bij Vies Grauw Weer. I think she brought the rose to Gerrits' grave in the dirty gray weather

Al, I am glad you can cheer for your brother!

I just came here to say that I found a file that was stored decades ago...

Zij Zwart (black, 0)

Bracht Bruin (Brown, 1)

Rozen Rood (Red, 2)

Op Oranje (orange, 3)

Gerrits Geel (yel

The publication part of the project is not equal to the entire book, but a larger "extended literature". For the "Elektor Electronic Magazine", there is indeed a lot to read about this aspect.

Therefore, the description of this article also explains-why and how-to benefit from the "leakage current of germanium-semiconductor components", which is often told only because of an unnecessary interference and error trouble, and this is falling into a certain special It is the physical factor for real use, directly from the generation of the preferred sound effects and through control of OTA-Currents. If you need support, just email me to jo2030_aeht_gmx_dot_net (English or German-reply will take some time, but every email will be delivered).

The circuit of the direct JFET buffer has been modified (two PNPs have been deleted, and the value of its Gain-Pot has been changed) because of an error in the dependence of Ubat. This is fixed.

The first released circuit can work, but the gain adjustment will vary with the audible value of the battery voltage, and the unit that is started earlier will require some modification.

If you are just printing the photo, the modification is easy to update, so nothing will be lost anyway.

Need to modify the battery usage (constant Ubat = Ext-Supply not required):

1. Completely remove Q1 and Q2 and connect the collector to the position of the transmitter

2. Bridge position of R35 and R36

3. Replace LD1 with jumper (bridge)

4. Connect the cathode of LM385 to GND

5. Change the value of R32, R33 to 10 kOhms (PT2-2 kOhms, may be changed to 10 kOhms)

6. Change the value of R34 and R37 to 560 ohms

7. Change the value of R31 from 6.8 kOhm to 22 kOhm

In order to get a better frequency response, I recommend changing C2 to a value higher than 1µF (it is better to use NP-Elko or "Samsung Hi-Qual Cercap" 4.7µF).

Multi-effect rack modules, as well as instrumentation amplifiers and floating diodes, are coming soon.

If you do not cool it down during the process, do not solder the Point-Contact-Diodes to the PCB as tightly as shown in the project Figure 2, because due to the micromechanics, this may fundamentally change the Diode- The data of Data (thermally effective) moves directly to the Point-Contacts inside the part.

Use wet cotton textiles at room temperature or similar temperature, but do not use ice cubes, etc., and do not use any air cushion before that.

Leave at least 5-10 mm in length on the diode pins on each side to optimize the cooling of the entire device when soldering.

You can also use crimping pins for this operation (as shown in the picture with the MD276 diode).

All this is preliminary and still in an experimental state. My simulation software says that all of this is ok, but it has not been tested yet!

The contribution contains a complete folder for downloading the entire update and more photos (will be changed soon!)-if you find any errors, please contribute to me too!

As stated in the project title, the real "real germanium sound" is generally considered to be very critical, but this means that it must be guaranteed by the working principle of the provided equipment and how to produce effects from the previously used components. Users can also get support from the administrator/instructor for this project here (please also refer to the text-I bought it under GE's antique and dusty shop, I bought a lot of GE-diodes from several companies for this project The supplier’s product may provide possible support for the selected/matched pair, as well as (maybe later provided) a prepared complete kit), and then achieve success on the performance equipment, which is for everyone who wants People who play electric guitars are very useful.

The project carried out a "more in-depth description" of the distortion effect, once again carried out a complete explanation of the actual use of OTA, and then provided some historical information and background of germanium parts, as well as some short stories or anecdotes.

In this way, this means not only articles and some explanations as technical publications, but also means to restore the interest of users, after all, to be satisfied with useful products that are practical and easy to implement, which also means real innovation. However, it cannot be a high-tech device, so it can be restored to the real "70s retro unit state" and continue to be used at certain times during this period.

Therefore, I want all readers to know that this project may have been published in the early 1970s, so this kind of thing came a bit late-or not? -The popular CA3080A-OTA was developed by RCA between 1967 and 1969!

(If you are interested in the amazing facts of this very developed and earlier industrial IC device, and are interested in this interesting background, then here is a link to Donald Tillman’s excellent website in the United States, which also has A lot of other very useful information in music electronics:

http://www.till.com/blog/archives/2005/06/last_of_the_ota.html

Like I think, this website is associated with a "must visit" for all guitar players!

)

The project described here shows all the ways to build an interesting and useful electric guitar overdrive device, one of which can be built on a weekend, the youngest electronic beginners can also easily complete it, and they are also ready to move forward like a guitar player And start.

For the first actual setup of the unit, the help of parents may then be needed to adapt them to the previously recommended and displayed PCBs, and then the text and all plans are processed step by step to make the final product achieve the desired performance. construction.

To start the project directly from here, the user only needs to know how the various parts of the schematic look like, and then glue them together to solder the single-sided printed board.

As the last addition to this project, I have tested the maximum possible conditions of all components on the breadboard and in the simulation program, and tested them under different conditions, and also performed some on different Spice models of the IC With changes, all the setting parameters of electronic components have been optimized to obtain the most commonly used units, which can ensure that they work as expected.

If the parts are fixed together, as shown in the layout diagram and schematic diagram, there will be no damage, so if all values ​​and positions are placed correctly and then connected to key parts, etc., it is vital. battery.

In order to enable the device to operate for the first time using only prints and some plugs, a jumper from the JP3-Pin1 jumper to the following terminals is required (a low-current LED LD1 for driving ota can be directly installed on the print on!). JP3-Pin3, but please be careful not to connect JP3-Pin2 in the middle, except for the cable shield of the foot switch.

The possible switches on JP1 and JP2 are only optional, if needed, and basically not needed at the first startup, so this situation can also be completely avoided.

In order to be finally fixed in the box, a switch for changing the diode path/sound is also provided. The plan shows the whole and the required configuration of the whole.

A pair of "anti-parallel diodes" are used to produce an overload effect, which is used as the main audio voltage generator to act on the sound product, and the modified guitar signal (Figure 1-VF1) is converted into different characteristics, flat Waveform (VF2) and interlayer are also called this effect, called "signal distortion".

If this effect is correctly achieved in a special way, the sound produced by the device will become very musical rather than disturbingly discordant, usually due to undesirable Any electronic device is caused by distortion. Most of these electronic devices are malfunctions, poor sound, scratching speakers, etc. Therefore, this effect is actually a different audio source.

In the context of the diode as the audio source, it seems electrically easier to perform this conversion with a "current source"-which is delivered by the OTA here-rather than ultimately using an operational amplifier for conversion. In any case, it will act as a working "voltage source", so it may cause more conflicts with the diodes and affect them. In the worst case, they will completely overwhelm their characteristics, so they may reject the preferred sound .

Based on these facts of the technology used, by driving a controlled current into the diode, the OTA can achieve functional coordination with the diode (the influence of the leakage current of the diode and its use are also widely considered!). . As the third component, it must be in the output component chain. This is a very high impedance JFET for the final required output voltage coupling.

Figure 1: Two diodes convert the sine wave of a guitar into different waveforms

At first glance, I don’t know much about getting it to work, but roughly speaking, there are many other things to say and know, because these settings have more reservations, backgrounds and possibilities in terms of the above distortion function. Therefore, the first description here should only be the basic nature of the subject and such main functional devices.

For the project, this is a difficult problem. If you look at most of the quotations for a few distortion and overload units, they usually come with an implemented and often needed signal output tone control chain. Normally, the user will A favorite position of all the controls is put together to achieve the best parameter structure. Each time it depends on the frequency range of the electric guitar used, so it is always independent. Therefore, compared to useful volume control, the required functions on the spectrum sometimes become more important, because part of the volume is also partially controlled by an external amplifier.

However, one version of this speeding project will be implemented without any tone control, and for the startup company, there are mainly three versions, all of which require the same PCB space:

Variant A-1: ​​All buffers implemented as JFETs (2SK30A-Y is preferred, can be changed to selected 2SK30A-GR, J112, BF245 or similar buffers), and there is no pitch control. There is only one used operational amplifier in the signal chain. If you are willing to do this, you should also pay attention to be able to control the frequency on a separate external device.

Variant A-2: Same as above, but with TLC272 op amp buffer (or TL072) to improve the availability of parts, as most TO-92 JFETs are becoming more and more rare, and sometimes may be completely obsolete.

Variant A-3: Both OTAs have subsequent op amp buffers, and the position is changed from "volume control" to the "tone control" used now, but ultimately has a JFET at the output of the device. This is the preferred method. For the first version of the first demonstration, there is no strict amplification part here, so users should perform this operation through an external device as needed.

Full description of all parts of this machine and most background

The final unit of the project on the PCB is not only some practical learning object, and then discard it, or even no longer use it, so it ultimately means to get a good sounding device for long-term daily use and bring a lot of fun.

Out of these interests, the project only describes the performance of a few but optimized electronic parts, and the PCB is prepared as a ready-made hand-sent Eagle-File, which can fit most existing "Stompbox- Flight-Case"-Like my first prototype, it was previously built in a simple bread box. In this case, it still depends on the use of friends and has been working to this day.

(In addition, and only provided according to user requirements, the layout of the PCB has been specially edited, and hand-made "teardrops" are optional on most soldering points to achieve true retrograde assembly and better electrical conditions. Monitor, as if the PCB was made on the basis of tape using the old layout technology of the early 70s, or simply painted with a glue stick.)

For users, this style means first of all to provide the best things and be challenged by innovation anyway. Regardless of the facts, both beginners and outdated Oldcrow face challenges in electronic products.

As a necessary supplement to the project background, this also benefits from the user's personal investment work, and then also benefits from some externally introduced and useful knowledge of the thing, which is collected on the components of each part and what knowledge is really needed The understanding of the structure of this equipment is not only as an electronic unit, but also almost as a musical instrument, combined with an electric guitar, so it is not only only required gears such as cables or other accessories, but also etc.

According to my personal experience, it’s hard to say for the basic equipment so required. With the help of my tutor and many other teachers, sometimes there is a little disadvantage when I am young, so I must always accept that such a performance chain is lacking. This is essential for these things, and then it is actually the fact that there is no money to buy this sometimes very expensive device, and it sounds great. Because of this, I was lucky at the time to be able to teach me how to do things and how to do things in my own words-in today's short words: DIY!

Therefore, another goal of the project is to solve those who will certainly not have enough money to buy high-quality electric guitars for start-ups, and the rights at that time, and now it really needs good guitar effects to play, because in the end, the guitar and The effector only provides a single music unit, and only when they work together and sometimes the user performs some well-performed and well-learned exercises, can it remain interesting. Power amplifier.

Picture 1: WN5457-1959-selected germanium-mostly do not look for high-quality germanium...

As the first major breakthrough of the project, this also means the challenge of the above-mentioned title and the sometimes very high price of such units (it should be said to be rough, the real uniqueness is becoming unique, and in each Under the circumstances, they are almost priceless!), so the used germanium parts have only recently been used since the 1970s, where they expect hundreds of euros or dollars, but then they can also do the job well.

It’s usually not easy to tell where the standard is on this information, or the difference is truly unique, so perhaps these prices are paid only for obtaining such high-quality audio equipment. In terms of classic sound and user satisfaction, but After all, we will still only use boiling water to make coffee-so to speak-when we look at the contents, every time there is a problem to taste what we see, that is, electronic germanium parts often contain some kind of garbage. Exterior.

Therefore, if the customer is first fixed on the device, then it is important to search for it with the special name of the known manufacturer, and then he can guarantee that he is satisfied with the product and can also guarantee the payment of the price.

Therefore, the word and slogan "germanium" is only a fact of internally used materials and technologies on the one hand, and on the other hand, it is necessary to start more rough machining, so you still need to choose, and maybe some other processing procedures. what is it then? Finally, it is also related to the name and quality/capability of the entire trademark or brand. At this point, the variability of DIY equipment is very large, and equipment owners can invest their personal qualities, efforts and capabilities here, which are also very important for the final product.  

A good example of these backgrounds is-for example-C. Chapman’s carefully prepared project "Elektor-Formant-Synthesizer", which can also be done in several ways (made by DIY, but also as a ready-made kit, There are also very good and pre-selected parts), which means that you can get acceptable results here, but it is also possible to get better results, and I have encountered a great instrument with very high sound quality and sound quality The ability to approach the legendary Moog-Synthys is even better. On the other hand, I also saw some formants, their sound is really bad, and the overall performance is also very bad. This is always right. It depends on only doing some work with them and preparing for the future. Get ready. Musical instruments are not only some electronic devices...but based on this fact, a rough DIY definitely does not mean less work with the same performance.

Therefore, it’s also important not to say that all these commercial devices may be counterfeit in some way (so please don’t get me wrong, but later in this project publication, I will tell a short story about An interesting thing that may be laughed at), it will make wrong promises when providing it, and make customers feel scared, but in the possibility of equipped with sound equipment, DIY projects can bring many benefits, motivation and First-hand knowledge, and save a lot of money in this way.

For decades, this has been known on Electronics-DIY, and here are some additions to this project. In fact, coupled with some kind of real innovation, stand up here to verify!

Focusing on the main functions of Overdrive-Effect, the circuit provided by this project provides some other functions in the form of a universal combination, capable of making good sound-producing equipment according to the characteristics of germanium, and can easily switch to the possibly very unique Silicon-on the other hand, equipment.

Maybe, if you ask about this scene every time and provide conclusive evidence, what you are saying now is that in one case, it is impossible to obtain really good germanium sound and excellent silicon sound, but just follow it here. What comes out of this is innovation, so the buttons are described in detail later in this publication!

As the second and major blow to this structure, the project uses OTA-IC as the core function of the generated sound effects. This is also a challenge to all commonly used Electronic-DIY`ers, among which these "operating transconductance amplifiers" are When many people in the electronics field need to be universal, there are still some difficult things, and there are few devices that they like very much. Therefore, the purpose is sometimes strange and sometimes incomprehensible, but I have to say that this may also come, because there is no useful OTA at all!

Since the early 1970s, the semiconductor industry has been developing rough operational amplifiers, but until today, thousands of operational amplifiers are still being developed, but in terms of quantity, all OTAs developed in history can be counted on with your fingers. Therefore, for decades, only a few useful parts can explain!

Figure 2: Simplified OTA diagram written by Eugene Zumchak, with internal IC functions

(As a normal knowledge of this situation, it should be realized that there is no industrial IC-OTA on the market, and it can provide a current of more than 2 mA at the output end!

I can’t tell the reason, but it’s a fact, and I can’t say it anymore, but if one wants to get a higher current value from the OTA than the above value, then all this can only guide a possible discrete solution (if needed Or need somewhere).

Perhaps because of these facts, what you are saying now is that this project may be just another helpless attempt to regain the deliciousness of old gum, but this is definitely not a fact, because it really comes as a new thing The unknown, or better yet, like this, the optimized and unknown possibilities, the special exhaustion of some semiconductor characteristics.

Here, you will also get the fact that the effect unit is highly dependent on temperature, which means that at around room temperature or above room temperature, this may just be a working unit that meets the requirements. If it doesn’t sound very good, Then play "Too Cold". Therefore, assuming that within a few hours in spring or autumn, the leakage of these parts can easily double in this fact, and then the entire winter may not work at all under the expected sound!

These are all physical properties of germanium and can be measured. I will add some data to these sentences later in this publication, but please forgive me. Now I clicked them because it means a lot of work. But I Will be updated.

Coupled with the ability to control the current on the OTA (actually only on this device), these facts are really surprising!

Figure 3: A discrete implementation of OTA-Overdrive-Cell, in which all used semiconductors are circled (for a more detailed description, please refer to this article)

By the way, that is to say, I have always wanted to know that I didn’t have this idea before. According to the current working principle, I need to use a small amount of electronic parts and OTA to complete the whole work. And here, I have always been interested in music electronics especially Analog synthesizer circuits are of particular interest.

Taking analog synthesizer (as a musical instrument) as the theme, there are OTA components everywhere in the synthesizer. Among them, voltage control circuits (such as VCO and VCF) require OTA, and circuit changes are often mentioned, using the cascade of "OTA units" Chain to achieve some audio functions, such as Filter-IC and so on.

Then there is the question about this idea, why not also perform the overload or distortion effect function on this OTA unit at the same time? So could this be useful?

(In Figure 3, you can see the simplified main OTA arrangement of Overdrive-Project, which includes four basic current mirrors-CM-equipped with some transistors, a differential input amplifier-dito, a very important clipping diode, And JFET output buffer.)

For startups with this idea, I can't believe that one or another famous Guitar-Stompboxes manufacturer (such as Electro Harmonix, Ibanez, Boss, etc.) does not exist. As a standard Overdrive-Effect, and implemented into the suitcase amplifier.

Therefore, when I started using this technology a few years ago, on such a distortion device with an OTA unit, I wanted to search on the Internet, and I found a lot of overload, distortion and blur boxes, and a lot of good people and www. adresses, the whole theme has a tip, and there are great life scenes around, but there is nothing new in new ideas, and it has been a well-known repetition for many years-every time I use an IC as an operational amplifier! (!! I got some good information from Don Tillman, about there should be some Gibson-Amp, and CA3094-OTA for the distortion mechanism, but as far as I know, these are also related to the Darlington-diode buffer , Which in turn means the use of effects. Although all possible advantages are not mentioned here, I have not found any of these Gibson schematics on the Internet until today. I am very happy to get some of them-if you know them , Please give me some donations!)

In addition, there are many practices on distortion circuits on the Internet, all of which have in common are the use of operational amplifiers. Almost at any time, clipping devices are configured as part of the signal correction and feedback loop, and extend from the output to the negative of the IC. Input, usually need compensation capacitor.

But I couldn't find any such configuration, so I used OTA directly. Then I googled "OTA, blur and distortion", but there was nothing...

I want to know a little bit, and then think of the fact that OTA may be the wrong thing, it may be that the available current is insufficient, OTA can only achieve a current of 2 mA at most, and an operational amplifier can provide 20-50 mA or more. Existing circuits, they get less, so this may not be a problem. To this day, I still don't have any reasonable answer to tell you!

This led all the initial ideas to the process of some tests using the rare metal tank CA3080A equipment. Then, I tried some experiments with higher drive currents on the clipping components. Here I also tried the hand-made and discrete implementations of SIL6-OTA, as well as a separate and very peculiar version, using SOT-23 and 1 respectively. : 1 Zetex-Lat-Sat transistor. Similar to the configuration of the circuit shown in Figure 3.

        Title item picture

Figure 2: The first OTA overload version, implementing Quad-OP, paired AA118 diodes and discrete SIL-06 OTA module

Then, about two years ago, the core functions were tested with several optimized units, and the parts required by the manufacturer were also provided with good usability, and then the main functional blocks divided into almost three parts were used to achieve the final The schematic diagram, the middle is in general, the said OTA-Cell is sitting, which will be described in detail below in this publication.

During this period, CA3080 and some other OTAs have been completely outdated, or are only very expensive in auction bids, and direct followers of DIL08-Packages CA3080-E, few NTE996. All these facts are put together-it is unacceptable and must be solved with something useful, and in the end don't spend too much money!

Therefore, the schematic has been changed again, and until today, the whole thing has to be implemented using National Semiconductor's LM13700 (the current name is manufactured by Texas Instruments), or as an alternative, using NJM13600 from Japan's JRC OTA is almost the same , And very useful, sometimes it gets better.

Although there are some voices on the Internet telling us, all these amplifiers can not provide the same audio performance as RCA or later from Harris to later Intersil's old CA3080A-Originals.

Therefore, it is difficult to say whether it has been tested or not, but the first obvious difference is the CA3080 chip, which is realized by an enhanced Darlington circuit, which is a direct component of the current source. They were not manufactured until 1999. Since the beginning of 1967, some old machines have adopted the very precise Chip-Process, which was previously carried out by RCA and was developed in the late 70s (only five minutes!) National-Chips. Using (only...) standard Wilson current mirrors. These ICs were also told that they were only designed to entertain and train certain students to create some chips in a certain possible competition, and were almost exclusively used to test new design software for consumer electronics at the wafer level.

See Mr. Don Sauer's very interesting "LM13600 / LM13700-Story" in his very popular Internet publication at:

http://www.idea2ic.com/LM13700.html

(Through this link, you can find a lot of information about IC development in the example of LM13600/700, but in this case there will always be some interesting consequences, and almost only low-level products are available, I tend to plan this The second version of the project and use another alternative solution, maybe not using those chips!)

The facts mentioned here are leading people to assume that the IC product is being developed quickly and hastily. Based on these facts and the above situation, people also know that some expensive semiconductor materials (pure silicon) are saved in the manufacturing process. Therefore, the overall transparency of sound performance may be slightly insufficient for ICs, mostly in a rapid transition state, with higher The current level may be in a pulsed state, but it is still unknown in the end, and then it is fully tested in various ways.

Therefore, judging from the playground of some professors, these ICs seem to be a kind of real CAD design, all interests are focused on science... And considering this and the appearance between the lines, I personally prefer the project unit It is implemented on JRC's NJM13600 (available from www.profusionplc.com at a reasonable price, the price is less than 1 euro!).

On the other hand, the real advantage of LM13700/NJM13600 is that they are dual versions and are designed for stereo use, so they could easily enhance the overload function and provide some necessary functions, which will be introduced later. In this publication.

Perhaps at first glance at the entire device, things seem difficult, complicated and the circuit is too large, especially for beginners, but after some practice and participation, one can easily get used to all parts of the device. "Step by step" work. Therefore, one of the goals of the project is to provide a practical tool for DIY-Guitar-User, which can be fixed in a few hours and can also handle the impressive "on-stage" used equipment . All of this is carried out to the product in a continuous manner, and it is possible to gradually learn about the previously used technology and all its background knowledge in a step-by-step manner (personal and required manner). End rough things by hearing all these things.

The parts used are almost standard electronic products, which still exist in the rapidly changing semiconductor market. Here, the continuous manufacturing process and the good availability of useful germanium devices are preparing such units as realizable, truly Another reason for the enhanced DIY-this project has enough room for expansion, and can also be used for self-made ideas and future experiments that users may conduct. Perhaps you can also find some new sounds in effects by modifying the schematic diagram!

I'm here to introduce you to a ready-made project, but it still describes a smart unit, and in the background I also keep a lot of ideas for enhancement, and I will describe some of them later (subject to change). This also means the following fact: everyone can see that all OTA-ICs seem to be obsolete in the next few years, and what will happen to the known production line of LM13700N at present.

Therefore, if they want to cancel the DIL16-Packages devices on these OTAs now, it will be a matter of time when they can use SO16´ers, because the industry only accounts for one million dollars in the economy and each cycle of the economy. A production line of commercial interest for the manufactured parts, so when these rules are cancelled product by product, we can continue to wait.

Today’s production, here only runs in the "as is" way, not in the "maybe" or "maybe" way. Therefore, if there are not enough orders, they will completely stop each production line, just like in the simulation synthesis The pain points of music devices are widely seen in companies, so no one can find a really good alternative, so by the way, they all tell us that digital music machines will always be the future, but in terms of this fact, I’m here to tell You, this is only part of the emergency exit, not (!!), so for the fast-growing DIY scene, it can help you tide over the difficulties, and learn more here. Users prefer DIL at any time Equipment, SMD parts without IC!

Therefore, I intend to provide some kind of actual project similar to a lifeguard for this case, and carry out follow-up projects on discrete OTA technology, but I need to keep this content temporarily, or keep it in the background for a longer time, etc. Wait, what will happen to the semiconductor market in the next few months/years.

It can be said that, unfortunately, perhaps all innovations will end in failure, and may not be realized all the way, and if LM741 is also brought out of the world market due to insufficient production, what will happen?

As an optional addition to the project, you can also follow a useful option, or better to say, the exact matching of semiconductors for this type of use, but it will not plunge the entire project into heavy laboratory activities because it can be completed The small amount of electronic parts added for this work is very accurate. These parts are prepared for the breadboard and can almost be performed by a good standard DVM.

The first important fact to start a project for DIY beginners here is that it is strictly forbidden to use any problematic SMD on this type of unit, and the entire assembly can be easily soldered together and can be on an optional socket Use DIL-IC.

Therefore, this unit has an advantage because it is also called "Vintage" with the actual TL072 and will continue (only possible) with the second version, which I will update in a few days to use in Cerdip-Packages The possible availability of some real "Vintage by 1982-TL074CJ-Black Top Opamps" (instead of using low noise 2SK30A-Y / -GR JFET buffers). This is coming soon!

Roughly speaking, the parts described here and used in the project will definitely be outdated. As mentioned above, it is very sad to see in the past few years (since 2005) that the popular CA3080 and especially the CA3280-OTA , And other high-priority synthesizer integrated circuits, and where the entire electronic music community is really hit by the semiconductor industry.

Due to the impact of these rules on the semiconductor market, there will be a second release version of this unit in the future (!! rough, only if there is enough feedback on the first one) to fully prepare for SMD. Before that, I There will be a full update, but here is the first setting, starting with a valuable and small budget unit available, as you can see here. Another reason for implementing this super-speed drive unit as an SMD version is that in the production process with through-holes, the PCB-Space on the double-sided printing plate is almost cheap. This is an attractive factor, so the only The single-sided version has a certain peculiarity, and even better, let us rarely say before that. Due to the mass production of PCBs today, this is a difficult reality, but very realistic!

1.) In the known standard size of 100 x 160 mm, cut twice from a purchased low-cost single-sided European card to get three cutable units (for all three variants, the size is 52 x 100 mm). This means that the project is well-prepared for the family concept and the kitchen production (and possible work sharing) of the entire guitar group. If you have no choice, each member will almost have a unique unit. The germanium clipping diode is preferred because it means that the rough tone of each unit will be different.

The smaller version of the device has only some parts and can be easily interrupted and tested on Expo-Strip-PCB (Vero-Board, breadboard) to try out all the parts, or just for tutorials. On the lowest version, you need 1 OTA (maybe CA3080, LM3080, NTE996), 2 diodes and an N-channel JFET.

2.) Variable and programmable input preamplifier, with good Lin-CMOS-OPAMP-Texas Instruments (TI) programmable TLC271, universal adaptive possibility for various pickups or other signal sources, but It can also be easily interchanged. It is recommended to use high-performance and high-speed Excalibur-OPAMP, TLE2037 (= Burr-Brown OPA627 equivalent, TLE2037C/SO-08 about €3,00 in element14/Farnell) in the input part by using DIL08-SMD-Adaptors . My non-commercial and only private component store with TLE2037A equipment can send a request via e-mail to support highly motivated readers of this publication!

3.) The entire signal chain can achieve low power consumption, with three JFET buffers, suitable for 9-volt batteries, but also suitable for 12-volt or 15-volt power supplies, and may be planned to be used as an internal synthesizer-effects module rack version . For 2SK30A-GR JFET, I can also give you some tips, you can get them here-there are several (German) distributors still offering them.

4.) There are four interactive main control potentiometers, which can easily switch the effect between silicon or germanium characteristics. The entire circuit environment provides enough possibilities to adjust all experimental changes or dynamic characteristics required in the future. This is also important and necessary, because different germanium diodes may be very different.

5.) The first accumulative overspeed capability when the input stage is amplified = the possible limit of the preamplifier on the enhancement (the triangle wave that the OTA will enter is limited to a sine wave!). If the user knows how to set up and change functions, he can easily modify all parts of the circuit as needed for special purposes. This possible mode can only be switched to the schematic with other unimplemented and not shown additional switches! Therefore, the resistance R10 must be reduced to another value of 1 kOhms -10 kOhms, and then the diode needs to be disabled and replaced with a resistor of, for example, 2 k Ohms.

Figure 4: Sharp/edge clipping caused by directly overloading the OTA input

6.) An additional and simple "absolute value converter", therefore a boostable Output-VCA, used for additional dynamic level control, depending on the intensity of the user's Guitar-Strike. It is also planned to change this part to ABV's operational amplifier solution to improve future enhancements in the implementation on SMD-PCB-Layout. This may also be the possibility of implementing enhanced Compressor / Noise-Gate Stage on the controls of the RMS converter. This means great possibilities for enhancement.

7.) Really unique and simple control from symmetrical to asymmetrical clipping function, fully selectable soft/hard characteristics of the effect, and volume level correction by using stereo dual potentiometers, where the user does not have to always change the characteristics The level of the external Poweramp can be re-controlled.

Figure 5: Symmetrical soft clamp when the guitar signal is overloaded

This is a very useful and very basic control, and the use of the pedal can also be enhanced by changing and optimizing one of the foot pedals as a foot control element.

Figure 6: Asymmetric hard clamp when the guitar signal is overloaded

8.) Through the "high leakage current germanium and silicon components" and additional selection and matching diodes, the real effect is obtained to obtain a truly real and musically smooth semiconductor overload sound, so there is no unexplainable effect never understood Magic in the black box background. Therefore, the user knows what he can really get from things and what he can get from things.

Let me say it again here: Proactive device users can request support via email from a non-commercial and only private component store (with matching germanium and silicon devices)! The instructions for selecting these components are as follows.

9.) There are really implemented "old design" on almost all components, including TO-92-JFET, DIL package and PCB layout, with round wires and software-generated shield wiring (copper-dumping).

10.) All parts are ready for future enhancements, and will always develop projects for users (not only products), and learn by listening and doing, which ultimately means overall fun, and for electronic beginners If there is no educational pressure, let me say that the first thing you need to do before is to be interested...

Right here, you can start the stage of soldering these things together, so please take a look at the main circuit of the device, and then take a look at the layout plan and let some suppliers provide parts.

If you want to use the recommended PCB, you don't need to think about it, but if you decide to build your own structure on Vero-Board, don't shield the OTA-Section too much, as this may greatly attenuate the sound to a large extent. The frequency range depends on the parasitic capacitance!

If you wish to additionally shield the object and have the advantage of blocking RF, you can apply shielding until the resistor named R10/R13 keeps the input of the OTA-IC almost unshielded. It is important to tell me that all PCB versions that I release without using SMD will have the small drawback of being more sensitive to RF induction, because its PCB wires are larger and longer (act like an antenna). If you are confused about this, the first solution to this problem is to set the value of the OTA's input divider resistor down, from 220 ohms to 150 ohms, and then set the amplification factor of IC 4. , Respectively increase the value of R6 (for example, from 22k to 39k, or from 51k to 82k)!

I hope this is not necessary anyway, but LM13700 IC may be different, and NJM13600 may also be different.

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