smd 101 resistor

Imagine you have a surface mount kit and you want to use solder paste and reflow soldering to make a mold, but it does not come with a soldering template. That is what [Honghong Lu] faced, she rose to challenge

. This is not a big toolkit,

, But her homemade mold can still effectively complete the work.

So, how to create a solder template from household waste? In the video we put under the rest area, she starts with the packaging and then cuts out a PET sheet from it. Its thickness is 0.24mm, which is an ideal choice. Then, she placed it on the PCB and marked all the pads with a marker, and then cut or drilled holes for the pads. Then the bottom surface is sanded to remove the protruding chips, and the template can be used in the normal way. She proved this by kneading the solder paste, manually placing the parts and reflowing the solder onto the hot plate.

Obviously, this is most suitable for a small number of large components, and we will never use it to replace a thousand tiny 0201 discrete device laser cutting molds. But this is not the point. It is an interesting technique for those less complicated circuit boards, and it can be tried by anyone who is curious about stencil printing and reflow soldering and does not have a stencil cutting project. . For that, we like it.

Making your own templates does not have to include this fairly basic method. they can

, Or

.

Love the low budget method!

If you happen to have a cutter and transparent printable paper, you can also use them. Even if I run 1000 pcb on a piece of paper, they still work for me. (A few years ago, there was an article about this technique here.

Even the editor, I can do 3D printing. If you are careful, its production speed is fast, the printing speed is fast, enough to support dozens of boards, and it costs almost no money. Even if there are only a few 1206 seconds, I would not bother to cut anything by hand

Great idea, please tell me, Sla? What is the thickness of the final mold? And layer height in use?

There are various tutorials on 3D printing solder templates on YT.

very good, thank you

You don’t have to go too far to find some good examples:

Can you do that with 0603 or smaller and 0.5mm fine pitch?

neat. I kind of imagined someone sitting there, and when I saw the title for the first time, I cut it open with a Xacto knife.

The effect of the exercise was amazing. I would love to see some cheap plastic CNC milling cutters with precision milling cutters to accomplish this task.

I think round holes are very effective for certain components because they have the lowest ratio of circumference (= resistance) to area. The solder paste will still flow.

However, it would be troublesome to redraw the PCB with a marker. Why not simply print the template on paper and use it as a template (on top or bottom of PET), or, if available, print it on overhead paper (if these things still exist)

Print on overhead film and drill holes. that is really good.

I forgot to add:

Round holes may be suitable for resistances as low as 0201 or even smaller.

But I do think you may have trouble with ICs such as QFNs with many leads and small pitches. For circular holes, you may not have enough solder before starting to overlap.

In this case, two overlapping small holes may be better, or use a small drill bit, then insert the drill bit into the hole and drag the sheet out slightly to form a rectangle

For many years, I have been using a polyester film stencil cutting machine to perform graphtec procedures with Gerber.

It is only suitable for any circuit board of various sizes.

I want to know if polyester film is suitable.

You can get thick plates with a thickness of 7 million. These plates can be cut well with a CO2 laser for use in paint stencils. But can they also use solder paste? It does not seem far-fetched.

I don’t know the behavior of military-spec polyester film sheets. However, buying ordinary 100µm polyester film as an overhead transparent film works well. Maybe I can optimize the cutting parameters more to reduce the burrs of partially molten materials. Kapton would have been better, but I didn't have it, and the thing I didn't have was time (waiting to order an orderly business template). Therefore, I took the CO2 laser cutting machine to my local hackerspace and took a spare FR4 PCB to scrape most of the cutting burrs.

0.5mm fine pitch IC requires some manual rework after reflow, but this method is much faster than manual soldering.

I have been using plastic film (usually a transparent window wrapped in cardboard) for surface-mounted parts masks. I have never been a loser. Before welding, I also use a thicker plastic mask to place parts on the board, and smd and tremor are usually not mixed together well.

We used it because it was convenient and fast from 2005 to 2008, before laser cutting templates were very cheap in China. In most cases, we use a thickness of 0.1mm~0.15mm, because we use them to print designs for PCB review, and also make a sfor test bench thicker in MFC. It is beneficial to 0603 components and larger than it.

At those times I only used a sheet of plain paper and a laser cutting machine, and only made 1-5 boards.

It can hold several boards. Many different thicknesses of paper can be ordered, and it is easy to obtain, and the dirt is cheap. (Typical 80 g/m² paper is a bit "thick", but for 0603 packaging and similarly sized equipment, it works fine.)

My weapon of choice for the template mold is Kapton film on Epilog Legend 75W laser. The combination of grating through the film and edge cleaning using vector lines can make the holes very small and precise, making QFN and BGA garage installations very reliable.

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Even for the simplest products, mass production can be a huge challenge. For example, you may find yourself spending a lot of time manually calculating and cutting strips of tape to match the DIY electronics kit sold on Tindie. [Tom Keddie] was in a similar position not long ago and established his own

.

[Tom] posted a video of his old machine after another Twitter user asked for help (watch it after a break), and he found that he had a lot of strips to cut. The frame of the machine is made of 20×20 aluminum profiles and laser-cut plexiglass. Using a 3D printed sprocket, the tape is pulled from the reel by a stepper motor, and it is fixed by a Lego wheel and tension spring. The second idler pulley with tensioner is used to guide the tape through the two photointerrupters, which can count the holes in the opaque tape or the components in the transparent tape. The cutter itself is an Exacto blade, mounted on a wooden block in the form of a guillotine, driven by another stepper motor and a screw as a lead screw. Everything is of course controlled by Arduino. Although it is no longer used, [Tom] said it worked very well that day.

Inexpensive laser cutting, 3D printing, and the advent of components such as aluminum extrusion and stepper motors have indeed enabled anyone to add some automation to production in the home workshop. You won't be surprised

, But we have also seen similar machines

with

. Let us hear about your production hack in the comments, or if you have recorded it, please give us a hint!

Hey

A few years ago, I built a machine to perform this operation and provided you with a quick video that might give you some ideas.

-Tom Cody (@tom_keddie)

This is definitely useful!

We use the "old fashioned" method, measuring the workbench and pencil with a tape measure. This is how it works.

Quickly figure out the pocket spacing on the tape part. You will find the pitch or pitch is 4, 8, 12 or 16 mm.

Next, you mark a vertical line on the left side of the workbench and perform some mathematical operations. For example, the count of 100 parts with 8 mm pitch is 800 mm, which is 31.5 inches. Therefore, to calculate 100 blocks of 8mm pitch parts, you will mark the second row 31.5 on the right. For 12mm and 16mm pitch parts, you will count in units of 50 and 25.

The rest is easy. You install the spool holder on the right side and pull out the tape. Therefore, for 530 parts with 8mm spacing, you have to stretch 5 through two lines, and then calculate the last 30.

A few years ago, I did something similar for the Blinkenrocket kit assembly.

It can cut tape and use markings to color-code parts.

Der Zerhacker appeared on hackaday.

But to this day, I still cannot cut clear plastic packaging because I rely on optical sensors to detect the holes in the strips for perfect alignment.

Now, this featured machine uses 2 sensors.

Like me, one is for the holes and the second is for the actual face value on the transparent packaging.

Now, I have seen this. In the next few days, I will upgrade den Zerhacker with a second optical detector.

Thanks to hackaday for posting similar projects.

This has inspired many people.

Hey hey! I will link it to the main text. Love Der Zerhacker.

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This year is the second SMD challenge faced by Supercon, so it can be said that we may have learned something from last year. If you are not familiar with the challenge, you can use some very traditional tools, and you must solder the circuit board with gradually smaller LEDs until you get the 0201 component. Even with the right tools, these tools are challenging, but even with the bulky and large irons we provide, there are a surprising number of people who manage to make them.

In the first challenge, we did find a problem. The LEDs are marked with polarity. However, since we do not provide ultra-high power amplification, it is often difficult to determine the polarity, especially on smaller parts. Last year, [xBeau] produced some fast LED testers to help overcome this problem. This year, we improved it.

As you can see, the 2018 model uses existing technology very cleverly. The probe is powered by the CR2032 holder, and the probe itself is two resistors. If you can use a probe to make the LED glow, you know which lead is the anode and which lead is the cathode. A little red ink makes it more obvious.

One idea is that these surveys worked well in 2018, so we can do more for the challenges of 2019. However, although these tools work well, they are not convenient to use. Small wires are not real springs, and will be fatigued after long-term use.

I want something that can better restrain abuse and have better ergonomics. I thought of 3D printing. Before trying to design something, I did a quick search as always to see if there was something similar.

On Thingiverse, [Tom20170] has

. This is a simple 3D printing for SMD test clip. It has a small flexible plastic coil and a housing for the breadboard cable, which serves as a probe.

Printing is easy, but I don't want to have too many wires or connections, so I ended up making two very simple modifications.

This is my bill of materials:

9 V capture is ideal. I got a better type, which has a molded body instead of the cheaper one, which breaks easily after 9 or 10 snaps. Their prices are indeed higher, but even if you only buy one, they cost less than $1. Saving fifty cents and disconnecting the connector every few months is definitely the wrong economy.

I did some tests with the Molex pins and determined that the bareness of the resistor leads is equally good, so I did not use the remaining pins. When I use them, I use heat shrinking agent on them. If needed, you may also be able to use Thingiverse to design the required wires.

The resistor is my hand. They are not very critical, if I have to do it again, they are one of the few things I want to change.

I used PLA to print a bunch of probe bodies on ANET A8 with a layer height of 0.3 mm. I used 20% padding, but this may not be very important. They don’t take long to print, so I can put them on the bed once, and then run a few times.

The resistor can be inserted well into the cavity on either side, and a little heat shrink will cover the solder joints. Use electrical tape or heat shrink to tie the wires on both sides to relieve all stress. As before, a small amount of red ink can easily see which lead is positive.

If you look closely, you will find that permanent marking is not the best way to mark PLA. It seeps into places you didn't intend to go. However, it is not very important to get positive results. However, if the colored area is clear, I would not use it to color 3D printing.

We really can’t be sure if anyone prefers tricks over bare resistor leads. The battery is removable, which undoubtedly makes the transportation of the probe easier.

The resistor limits the current based on the forward voltage of the LED. Generally, the voltage drop of the LED is between 1.8 V and 3.3 V. Using 100 resistors, its operating range is 13.5 mA to 21 mA. The high end is a bit overheated, you may be able to safely increase the resistance value. Using two 470Ω resistors, the current is approximately between 3 mA and 8 mA. 1kΩ is fine, but it may be a little dark.

Instead of using a higher resistance, I thought of placing the second LED in series so that the tweezers can double as continuity probes. For example, if you short-circuit the probe, a 1.8 V red LED will see about 12 mA of current, but it will still make most of the tested LEDs get 5 or 6 mA with a 100 resistor.

Of course, if your multimeter has a diode setting, it may be the right tool for this job. If the device lights up, the positive probe will indicate the anode of the LED. If it does not light up, switch the probe.

If you look at the LED data sheet, you should find a way to optically identify the polarity. For example, some have green stripes, dots or notches. If the lens is transparent, you can also understand the polarity by paying attention to the connections inside the LED. Sometimes, the shape of the pad will tell you. If the component is on the reel, the reel usually has a way to tell you, but if you only have some scattered parts, it won’t help you.

see this

. You will see that the terminals and pads look a little different. This from

A cut-off angle is clearly shown. You can see many examples here

.

If you want to know more about the SMD challenge, please check

. Maybe you like yours better

. However, if you do make a pair, please post them and send us a link. At the same time, you can start practicing next year's game. It is never too early.

When you perform this operation on DEFCON, a part data sheet will be provided in advance. I use it to optically determine 0201. I can easily see the rest.

Using the same title photo as [Dan] makes me wonder if there are different HaD authors writing the same story on the blog.

(It’s not that it happened before B^)

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What is your favorite resistance value? 1K? 10K? They are all good, but when you hardly need resistors, nothing is better than the old zero-ohm resistors.

Wait! The resistance should resist the current. What is the use of zero ohm resistors? Well, the short story (Tee-hee!) is that it is like a jumper for a single-sided surface mount board. In the bad past, companies often saved costs by running a single panel, and you could buy jumpers to help simplify the layout.

Fast forward to the modern era, where there are no through-hole components. What is the resistance (ideally) of the wire? Zero ohms. So zero ohm resistance was born. In 1206, we placed a complete spool in the closet, which was the largest SMD size we used, with the goal of being able to sneak two to three tracks under it even on a homemade etching board. They are great.

Anyway, what makes us start to subvert the lowest value resistor is

. Of course, nothing has zero resistance. This article will take you step by step to understand some of their actual properties. Please enjoy!

Damn, my master plan is to weld thousands of animals into a ring for superconducting current storage.

In any case, the solder joints will help you.

*will have

The third stage, profit

I work in a place that often handles temperatures below 10 Kelvin. At this level, you must be aware of solder formation.

~However, there is a limit to the current that can flow through the material before the material loses its superconducting properties.

It doesn't matter, you can place a parallel between the joints... hell, just to make sure that each side is ok. ;-)

What an ugly board, eroding like hell :)

It is actually a pit and full of toner. It's ugly, but it's been four years since I entered the password, I've smuggled the password in my pocket and bag,... I licked it and kept ticking. No complaints.

But yes. On the surface, she is not the winner.

(Oh, you think the corroded part may be the "G" I wrote in Sharpie, which means the ground pin on the programming pad.)

Hey, Sherlock, my brain detective, is still spinning with things on Atmel and USB, maybe often in his pocket? Because the corrosion looks the same as the old phone, it took me about 5 years.

Wabi-sabi (Wabi-Sabi) electronic products.

What is it?

In the middle of the photo is the 680 series with 000. Is it easy to bridge traces with only 680?

"In 1206, we had a full spool in our closet. This was the largest SMD size we used. The goal was to sneak two or three tracks under it even on a homemade etching board."

Since 680 is not 1206, maybe you can use 680 and 000 at the same time instead of buying some large 680 to be faster?

good idea! I do not remember. Maybe I didn't have the technology/method to reliably pass the trace under the smaller (0805?) 68 ohm resistor?

Soon after I moved, pitting on the copper made the circuit board old and had to use a color laser printer for a terrible transfer. In retrospect, my heat was also very high at the time, so I often stained the marks during the transfer process. I bet I just don’t trust myself and don’t want to clean up.

Technically, they are called zero-ohm "jumper wires", not resistors. As you pointed out, resistors...resistance.

I want that shirt! ! ! ROTGL !!!!!!

No problem, it must be here

Maybe elsewhere (maybe there is also eevblog-shop?)

I don’t know what "ROTGL" means...

Maybe he is one of the country huts with heavy soil on the lower level, so he can only roll on the ground with a smile, not on the actual floor.

Laugh on the ground? Is this some kind of joke?

that's nice! That's really smart, I will definitely use zero ohm resistors as jumpers on the next board I make. thanks for your hints!

Again, here I am stupid because I didn't think about it early, which is much better than trying to queue 2 layers.

Therefore, my daily work is an engineer for an aerospace company; I am developing and testing weather satellites in civil aerospace. In the last month, I have been troubleshooting a flight card that will enter a module scheduled to fly in 2018. The module was designed in 1997. Due to the discontinuation of some components, the last design change was in 2009 for the main communication protocol chip.

Use the new chip for the first test. The board failed. Cannot establish communication with the test PC. Contact the chip manufacturer; this is listed as a "substitute." Suppliers view our schematics. "You have a 4.7K Ohm pull-down resistor on both pins. I have seen some leakage currents before and the deception logic is very high. Replace a 0 Ohm resistor and see if it works."

There is a technique to shorten the resistance pad on the engineering board. Gosh, it works.

The 0 Ohm resistor is the new resistor of choice.

Well, I can't say that I don't know anything, but the 4.7K pulldown will make me scratch my head first, and I will never think of using anything over 1K that I want to pull down.

???? 4.7k is the "standard" value of the pull-down resistor. Depending on the type of signal and logic device, I even used values ​​as high as 100k.

4.7K is the pull-up *pull-up* value.

Please explain further... Why are the values ​​of the pull-up or pull-down resistors different? I have always thought that 4.7K is the *standard value.

Except for CMOS, Vih is farther from Vcc than Vil.

This article describes a chip that has been re-run to replace the old chip. The old technology requires lower values ​​(usually) and also has asymmetric input characteristics. An example is the original TTL technology, which has a higher bias current, so the pull-up *up* is about 4.7K, and the pull-up *down* is about 330 ohms.

Newer technologies such as microcontrollers have very high symmetrical input characteristics. For example, the internal pull-up resistor on ATmega328p-pu (the resistor used on the smaller Arduino) ranges from 20K to 50K. I can't find the input impedance right now, but as you can see from the memory, its order of magnitude is 100 of K.

If the through-hole resistor you are using is a very large inductor that has been adjusted inductance, the lower value will be used more to shunt any voltage that may be induced into the "inductor".

Okay, I found the input impedance. The reason I haven't found it before is that it is designated as 1uA leakage current of I/O pin with Vcc of 5.5V, which is about 5.5Meg ohm.

@grab:

"Except CMOS" :-) I regard CMOS as the standard of today's electronic products. Therefore, the logical threshold is usually in the middle.

Do you own shares in a power company? :-)

Or worse battery manufacturer?

4k7 has wasted 1mA (@5V), I mean, of course, it depends on the voltage level and the required speed, and sometimes it is necessary to reduce it to such a low level.

I always use 10K for pull up or down. I have no reason why anything else I use 1M b/c here will extend battery life except this battery-powered radio switch.

Ah, you can enjoy the freedom once!

I would be very careful when using a 0 ohm resistor on the non-power pins of the IC, because it may cause the ground impedance to be lower than the power pins and may affect the noise immunity. Due to the chip design, this is not a common problem, but once it happens, it will take a long time for you to find it. 5-10 ohms would be a better choice.

My favorite resistor is 1.1k 1 / 4watt.

Around 1976, I still had a leather bag in a bag for only a few dollars. Import from a well-known American company, not cheap import.

Very suitable for use at any time when 1K resistance is needed. And their leads are very long, different from the resistors I unplugged from the circuit board.

I have some more today.

Michael

A few years ago, I got a killer deal of 200 1.2k resistors.

I have some 0 ohm resistors in the standard 1/4 watt style package in the resistor box and they are stuck with the flooded old stereo amplifier. It has only one black stripe and I want to know how I will deal with them.

Yes, I have some myself. There is nothing better than this sexy stripe. It has never been used before, and may one day be used for some art projects.

I use them as arms on cyborg earrings :)

I use them for exactly the same operations as in this article, jumping along straight lines on a single-sided household etched PCB. It's really just an aesthetic. I prefer the appearance of a "resistor" rather than a little wire, but it is also easier to plug in. If you want to do "top welding" and trim your legs flush, the main body will use them The blocking bottom is a flat surface.

I have seen many 0 ohm, 0%, 1/4 watt lead resistances, at least the color code seems to indicate: black-black-black-black

The company I work for uses them as voltage selectors in power supplies. All three are 120, these two are 240, and so on. The default value is 120 (for partially assembled instruments) for initial testing (then aging and final testing are modified).

I saw the types of through holes in the first one on TV. When setting for different countries/regions with different transmission standards, a 0 ohm resistor is used to select the properties of the area, so *only* needs to change the bill of materials, not the entire schematic and circuit board.

I have always been confused about how to calculate the power rating required for zero ohms. ;-)

Even more confusing is the percentage tolerance of zero ohms. Can I develop negative resistance?

Very simple, (actual-nominal) / nominal.

I think your formula is no longer valid; regardless of the measurement, I will keep getting 255.

With this equation, I have a very small number on zero... theoretically I should have a ∞W resistor...

They are already rated current. The current of 1206 is about 2-3A.

Depends on resistance:-)

Once provided, some types can only guarantee <50mOhm. Calculations show that in the 2512 package, they have poor performance over 2A at higher temperatures. But they exist in the form of solid copper, suitable for 100A

Be careful when buying them: be sure to use the 1% version and don't be fooled by the poorer 5% version!

I got 50% cheaper dirt from Elbonia and I still think 0 * 1.50 = 0 :-D

It seems that the resistor in the picture is a "bridge" of a trace.

Is it safe to use this way? Is there no real opportunity to short-circuit below?

They are made in the same way as ordinary smt resistors, and the bottom is not conductive.

That's all of them. Otherwise, if the traces are adjacent to each other, why use a 0 ohm resistor instead of just connecting the traces? ; P

Sometimes you need to use resistors for some hardware configuration, I also saw optional antenna filters (in the GSM world) where the inductor is shorted to the 0ohm resistor.

Like a bridge over the traces of trouble?

No, they are ceramic underneath, at least the normal thick film type

They are also used as configuration jumpers and isolate the parts of each test (installed after the test).

I was looking at the development board a few days ago, and it has all these uninstalled 2-pin x connectors. The schematic shows them as configuration jumpers. Turn the board over, and then there is a small (0405?) 0 ohm resistance bridge through hole instead of a jumper.

However, this is great for segmented testing. I will have to remember this.

Yes, I have a project where the EE guy cleverly disguised this thing: there is a PI filter on the power line of each subsystem. Therefore, when you debug, you can isolate the subsystem by removing the inductor, but in production, if you see that the PI filter is not necessary, you don't actually need to fill the PI filter, you can use a 0 ohm jumper. No rotation.

Yes, that’s what I’m talking about here: when power is on, we place them everywhere to isolate the circuit group, and most of our ATE boards have a large number of unfilled 1206 points, and we fill them on each board These points so that ATE can recognize which board is used. It is much easier than serial eeprom.

Not long ago, I ordered a batch of 1,206 0 ohm resistors from Digikey, and they sent me a batch of 500mA fuses. I'm a bit entangled in how to answer, because, well, they work very well, so they are not the wrong part, but not the right part.

There are two more on my current board: it has three power inputs, one for logic and two power amplifiers for logic control, so even if the amplifier is short-circuited, you can guarantee that the logic will remain valid. On the evaluation board, for ease of use, we loaded 0 ohm resistors between all three power supplies so that it can work with only one power supply. Similarly, its purpose is to use uC on the same board and have short traces to the chip. If uC is in other places where the trace/off-board position is longer, we will provide a package for the rc filter, but bridge it with zero for use.

Oh, on the ATE board for high-precision current measurement, I often put down four footprints, two in series and two in parallel, so that I can load resistors to accurately obtain the required detection value. If I am lucky and find a suitable resistor, I will put a zero in series with it (and hope it is actually zero, but this is the purpose of four-wire resistance measurement.)

This is why I like Hackaday.

I remember that it was the first time I saw them in an Otari MX-5050 eight-track reel-to-reel tape drive. The 1/4 watt resistor beige package as described above, with a black stripe. what is that? Actual measurement, zero ohm. We just started laughing.

Yes, it must be admitted that when I first encountered them in the 90s, I thought it was some engineering Easter egg joke.

As far as I know, these resistors exist because the assembly machine (for THT) cannot handle bare wires.

I just want to know if an infinite ohm resistor is available somewhere?

Of course, but they are divided into two parts;)

In fact, the linked article talks about a company that uses 0 Ohm resistors in useless places, and the resistors are not marked in various colors to prevent reverse engineering.

Therefore, perhaps some companies also use counterfeit infinite resistors for this purpose, placing traces and placing parts with only solder pads and no internal connections.

Once they were rolled up in a "spare" box, this was called a "package short".

I use them as ties. Because network connections are evil.

They can also be used for (low precision) current sensing resistors and as fuses.

Just because they have a rated current does not mean that they will act as fuses. If you need a fuse (for example for UL/safety/legal compliance reasons), you need to use a fuse.

Removable Pololu A4988 stepper driver modules use them as current-limit detection resistors, and it is not uncommon for the ICs on these modules to emit deadly smoke.

Shockingly, I have seen them used as fuses in E-POS devices. Even ferrite beads are deliberately too small to act as fuses and emi filters.

Although no one has ever exchanged in this field, we do have a unit to return, and the sub-board is actually charcoal!

The daughter board provides power to the operator's face-to-face display, touch screen and display data.

However, the cause came later: a cable (similar to a small SCSI) was severely worn, cut and burned.

Lesson: Not a fuse! ! ! ! ! !

These resistors are also useful when creating new circuits that you are not sure about.

For example: Create an RS232 line and worry about ringing? When something goes wrong, put in 0 Ohm and swap it with the "real" resistance.

^this x10 ^

New designs, early prototypes are still playing a "hypothetical" role. Just sprinkle them on the board, and there is even half the chance that they might be useful later.

Then, one of my favorite tricks is to use them in a "pair" on the TX and RX lines of the serial connection. With a little thoughtfulness, you can use two of them side by side to reverse the RX and TX connections (horizontal and vertical).

I just did RX TX on the prototype board. Had to make a record for the next guy on the silk screen.

You are wrong, you are all wrong. It is the ultimate current sense resistor. When my Kickstarter launches erer, please read all related content.

On my project audio preamplifier, I have an output op amp that can operate in unity gain mode. If you want to get a profit, enter 1k or 10k, etc. (and the matching front end R is the same); however, if you want to get uniform gain and there are smd pads on the board, you can use 0 ohmR. In fact, I bought the first bunch a few weeks ago. The previous board speed allowed gain, but I want to configure this version to get unity gain. The ugly way: disconnect the leads of the TH parts as a bridge between the pads. But 000 is cuter than the black line on the board;)

Can a zero ohm resistor not be used as a simple type of thermal sensor? Increase heat and increase resistance.

This is zero meaning.

You...good job :)

Zero has been around for a while. They were found on boards for HP2100A small computers in the size of 1/4 watt through holes in the early 1970s, even before SMT was envisaged. That is double panel...

Thank you for pointing this out. I read this and said, "Huh? Is zero ohm resistance a surprise?" We have HP, and these are the springboards.

Yes, starting from the old joke about zero ohms before surface mount, if you want to divide by zero, you can solder with an analog quantity, then solder the zero ohm and divide by zero, unfortunately, it always leads to components Damage or short circuit

Well, if you get a 1v power supply and a zero ohm resistor, then mathematically speaking, you will get unlimited amps.

If you then use infinite amperes and use it to pulse the transformer, then you should get the infinite ampere voltage minus the losses (still infinite).

Unlimited voltage and unlimited amps provide unlimited power.

SSH, keep secrets. Don't we want those guys with too many units to figure out one person now?

The above logic is based on the text joke of a person sitting on a chair and jumping out of prison.

I just like to read short stories.

So far, I don’t know how useful a 0 ohm resistor is in my life!

-Single board bridge

-"Not sure which resistor or capacitor to place" placeholder

-Easy to test probe

-Switch the purpose of the board once

Machine can place wires

-Landmines that are reverse engineered when disguised as other components

-Reference for testing other resistors

-Cheap test oven settings

Joking with other engineers

-Projectiles of the Mini Railgun

And embedded in the black powder rocket engine for electric launch.

Make sure you get a high-quality 1% metal film 0 ohm resistor with a low temperature coefficient!

They can also be used as jumpers for things that the user does not have to change. You can change the jumper settings by flipping a bit on the pick and place machine, which is cheaper than through-hole jumpers (needs to be inserted manually) and does not need to throw away the PCB inventory for small changes.

Resistors with values ​​less than 0 ohms will be very useful.

There is not enough market to produce it as a standalone device. You must do it yourself.

(Hint: operational amplifier)

Quote: "Of course, nothing has zero resistance"

What about the negative resistance used for the chaotic oscillator 99 in Chua’s circuit?

These are also used as the main components of the black noise generator.

I have a very old radio (70s, maybe early 80s). It has a circuit board, but everything is soldered on the circuit board by hand or through the circuit board.

It's dead, so I opened it just to look around. It has a zero ohm resistance at the location where a wire is cut short. Resistors have additional contact points, which can be soldered together. The bulk of it is actually mounted on the board.

I need infinite ohm resistor

Place contact A in the center of the known universe...Place contact B on the PCB. Start to leave contact A... Stop when your resistance approaches the required infinity.

^Ahahahaha

The 6 amp fuse or solder bridge does not work?

Some ham transceivers use tiny resistors (zero or non-zero ohms) to configure the gears. Tailor the correct frequency band, and your ham-only radio can be transmitted elsewhere in the HF spectrum, including marine radio frequencies. In a pinch, your ham radio can double that of an expensive marine radio.

I started doing this when I started working on the toner transfer surface mount board-no need to drill jumpers!

Regarding through-hole 0R resistors, there are usually two types: one is that the main body is a ceramic block with carbon or metal film flashing, just like ordinary resistors; the other is that the main body is metal (usually copper) or contains Iron thing, I don’t know whether it is steel or iron, etc. These are very useful for lead legs on small modules, especially if you can purchase various metal bodies-leads become current limiting.

Sometimes called "machine pluggable jumper."

I work for a small and medium-volume EMS (Electronic Manufacturing Service) provider (also known as a contract manufacturer) and perform a quick system check. At present, we have provided 18 active part numbers for various 0 ohm resistors, the total number is close to 160,000. All components except 3 are SMT, and the package size ranges from 0402 to 1206.

Sometimes I use a 0.5 ohm resistor as a jumper from the SPI line to the EEPROM. It is very helpful when laying single-sided boards...looks much better than jumpers...

But don’t forget that if the application does require a fuse, you should use an appropriate rated fuse...

In our voltage distribution unit, even a mobile wrench is a fuse. Its grade is about 3 Gelignite, and has the additional function of dismemberment.

In the past life, I worked for a computer manufacturer. The company that designs our motherboards will place zero-ohm resistors in all the data lines of the serial, parallel, front panel audio and PS2 ports, while there are still these resistors on these motherboards. We will send the circuit board for FCC test, and then fail, and then start to replace the zero ohm resistor with ferrite until the test passes. Why not place the ferrite in the first place? Their cost far exceeds zero ohm resistors...

I think that if necessary, a series termination resistor (a few 10 ohms) can be used instead of zero ohm resistance.

It might be so. Since I have been working there for many years, I really don't remember the details.

I built a lot of things on a single-sided Perma-Proto board and found that 0Ω through-hole "resistors" are very useful for jumper wires (easier than bending the wires to the correct length) for power wires or over the center. Divide. They are super cheap in China and much cheaper than pre-made jumpers.

I remember someone told me that a zero-ohm resistor small enough was inserted into the via.

The story is: the traces in the vias act as inductors at RF/microwave frequencies, and resistors help eliminate this.

I have never ended such a high RF job, but I remember this story.

The confusing story is, but the size of the hole in the microwave oven window will let you know how big the hole can short-circuit (or reflect) microwave energy. You will not get microwave energy through holes of the same size or smaller, so you will forget to send microwave signals through through holes.

You will see that in all high frequency PCB antennas, they are only on one side. I via is a reflective pile that will reflect most or all of the microwave energy.

Can we just use wires as jumpers?

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This is the clever trick for your next 3D printer construction or transformation:

. We bet it may have many other applications.

Traditional load cells, at least those you can pick up cheaply from usual sources or harvested from old kitchen or bathroom scales, are usually too large to be used on the extruder of a 3D printer. [IvDm] Want to make a touch sensor for it

, So he built his own load cell to complete this task. It is composed of four 1000 ohm SMD resistors with 25 larger device sizes. He mounted them on an X-shaped PCB and wired them in a classic Wheatstone bridge configuration with two resistors on one side of the board and two resistors on the other side.

The extruder is installed in a hole in the center of the board and floats on the board. Through the HX711 load cell driver chip, when the extruder hits the bottom of the bed, the bridge can sense the slight bending of the board, and ATtiny85 pulls the limit switch input to the ground. [IvDm] even performed some repeatability tests on this sensor, and the results were unexpectedly consistent. About the first minute of the following video shows how it runs on Hypercube.

We found that the use of SMD resistors as strain gauges here is very clever, but it has many relationships with off-the-shelf load cells:

,

, Even

.

Thanks [jschoch] for the hint.

How does it work? Is it related to the carbon in it?

This is really interesting.

Damn, this is so smart. I understand how it works, but this is one of the things that I may not consider impractical. I am surprised that it actually works.

If you understand how it works, why are you surprised at how it works?

This is like the experiment of ether wind, or the complex, broken and hardened stone blade made by early humans. You know it is possible, but it can work well for a small amount of money.

Because although it can work, the desired effect is still one of the criteria for resistors specifically designed. They should remain stable under temperature, aging and mechanical stress. Changing its value through mechanical input is usually called a microphone. I bet that the cheaper the resistor, the better the effect.

Durfus mounted (intentional) resistors are usually film based, so if you engrave a zigzag conductive pattern on the film (thin or thick), compression or stretching will change the length of the pattern and change the resistance

But only one point... although it can be measured

Osgeld

Zigzag is not really relevant: it is a method of impedance matching and has the side effect of introducing anisotropy. Fortunately, most SMT resistors are not made this way (except for some ultra-high resistors).

Almost all SMD resistors (especially in the 1 kohm range) are metal films. But no matter what, it works by bending the resistor to stretch the metal film, thereby increasing its resistance. The number is small, but it is enough to measure.

This is a clever design! I want to know whether the designer has calibrated the output volts/mm deflection to understand the sensitivity/repeatability or possible stress on the solder joints?

One possible way to get higher sensitivity from this design is to place a small groove on the PCB directly below each resistor. The slot will slightly weaken the area of ​​the PCB, thus concentrating the bend here instead of spreading it over the entire arm. At least it's worth a try.

*route*

Drill a hole

Mouse bites?

"Rout" is correct. You use a router to eliminate a slot. "Route" is a path.

No.

Rout-verb-hollow out or cut out grooves or patterns on the surface

Moreover, the definition of "route" does not include this definition.

Or you can use strain gauge

They even have similar dimensions to resistors.

I guess they should start making SMD strain gauges :-)

Yes, but these resistors cost less than 10 cents. Even cheap strain gauges are only about $1.

It would be great if something like this can be proven to be sufficiently repeatable and robust for a given application.

They may be cheap, but due to the stiffness of the ceramic substrate, they are not sensitive.

Agree with the clever "why didn't I think of that" thing.

A quick look at the linked files did not find out whether they use thin film resistors or thick film resistors, but I guess the thin film would be better here (lower noise, higher accuracy, lower temperature coefficient, metal and oxide resistor elements ).

But now I think about it, why not just use bent copper traces as elements on the PCB? Using the 6 million rule, you can easily get a 2-inch trace in the space of 2512 components. The resistance is still low, but the noise is low, and the mechanism is not bothered by solder resist and very hard ceramics for resistors.

If a proper (low-Z) amplifier is used, I bet the sensitivity and noise performance of the PCB trace will be better than resistors.

At least for Delta printers.

The designer even puts the driver circuit on the effector.

I have not seen the PCB trace variants of Cartesian printers, which may be due to the variability of the installation style.

Does anyone order PCB from JLCPCB for this? I will spend some money-the minimum order quantity is 10pcs, I will choose 2 :)

What's really surprising is that the parts they make are actually designed for this service, called strain gauges. I suspect that they are not as cheap as SMD resistors, but in most cases, I like to use parts that are designed for me to use them.

The first problem that ensues is mechanical creep in the solder joints, which is under pressure in this design. When using a strain gauge, the strain gauge itself is flexible and does not bear mechanical forces-it only deforms with the base material, and is designed to do so so as not to interfere with the mechanical device.

Therefore, the most likely failures after multiple load cycles are: a) The solder joints begin to conform to the load, and the zero point of the bridge gradually deviates from alignment; b) The solder joints produce whiskers due to RoHS soldering and mechanical strain. , Eventually leading to a short circuit; c) The solder joint is broken.

As long as you don't want to sell the device, you can easily solve the points b and c: avoid the use of of-pin (RoHS) solder. But I also prefer to use suitable components at work, in this case strain gauges.

You can of course use the zigzag traces on the PCB itself to do this.

(But don't you want to measure the height of the extruder without pushing it into the bed?

I think capacitive or inductive induction is better. )

I often wonder why people don’t just make the bed conductive, but use a pogo pin probe. Effectively replace the sensor with a switch and perform the measurement directly.

This is an example of a PCB-based load cell.

Thank you. It’s great that my main concern is the space required for this. Cca. The top and bottom layers are 12 square centimeters. I don’t know if this is useful without an op amp.

It's not like how much money has been spent on Ali for load cells and UV resin these days...

But yes, I think this can also work :-)

You can also just make a PCB with tiny swing lines and measure it.

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