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Review: Transistor Tester | Hackaday

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Amazon's recent recommendations are getting more and more creepy. Every time I log in, I see a list of new Blinky LEDs, Raspberry Pi accessories, Arduino shields, etc. Like they

I. When they recommended a $22 transistor/component tester, their customer database paid off. I have seen a lot of testers recently. Curiosity made me better, and my mouse found a "one-click purchase" way. Two days later, I was holding a "SainSmart Mega328 Transistor Tester, Diode Transistor Capacitance ESR Meter MOS / PNP / NPN L / C / R" in my hand.

I will remove the obvious obstacles. This thing is cheap to build-as cheap as a factory made. My particular device came with a soft LCD flap and hung on its flexible cable. After reinstalling the LCD back into the acrylic backlight frame, it was found that the distortion at the same bend was somewhat worrying. Thankfully, there is actually no damage, although I do hope to provide some protection for the flexible cable in the future. talk about it later. The circuit is open to the world and can be seen on the bottom of the tester. The heart of this unit is ATmega328. It is supported by some transistors and a few passive devices.

I don't have much expectations for the tester, but I hope it can at least start. Connect the 9-volt battery and press the magic button to bring the tester to life. Since there is nothing in my socket, it quickly lights up and displays the manufacturer information-"91make.taobao.com" and "Efan&HaoQixin", and then it tells me that I have "No, unknown or damaged parts".

I put a few resistors around the workbench (not everyone?), so I put one. The tester reads it as 9881 ohms. Sure enough, it is a 10K 5% resistor. Capacitor-ceramic disc, electrolytic and surface mount can all work normally. The tester even provides an ESR value. The real test will be transistors. I pulled an old 2N2222 with a TO-18 metal can and popped it into the tester. The damn thing worked-it shows the schematic symbol of an NPN transistor with its collector, base and emitter connected to pins 1, 2 and 3 respectively. It is also possible to flip the pins and retest. The tester shows that hFe is 216 and the forward voltage is 692 mV. For 2N2222, these two numbers are reasonable.

The tester works well, and surprisingly-it can correctly identify BJT, FET, and even esoteric parts. The only thing it prevents is the linear regulator, which is shown as two diodes. The regulator is just a simple device, so I can't blame the tester there. The returned values ​​are also reasonable. Although I don't have a calibrated laboratory, the numbers are consistent with my Fluke meter.

So what drives this little tester? There are about 20 versions on the market, all of which are from China.

 It is a seller on taobao.com, usually called "China's eBay". There are no less than 7 versions of transistor testers on 91make's homepage, including various enclosures and LCDs. Some digging discovered the history on the device. It turns out that the transistor tester is a


) Was originally created by [Markus Frejek] and by [Karl-Heinz K? ubbeler] and some others. of

 The project shows that the project is very active and the last check-in was only a few hours ago. The project is also well documented. The English PDF is 103 pages, explaining the working principle, the circuit itself and the software. The document even explains some shortcomings of the Chinese version of the tester, including the use of Zener diodes, and the original schematic requires the use of an accurate 2.5V reference voltage. Yes, it works, but it will not be as accurate as the original.

Considering that each manufacturer adopts its own version of the quality and design changes, the developers do not officially support the clone that I can understand. Have a

 Cover these testers. Some can be modified to be closer to the official version. In fact, using ISP tools, brave hackers can update the firmware to the current version from [Karl-Heinz's] repository.

Therefore, the final conclusion of the tester is that it carries a little warning. The cost of these testers is reduced (the cost is as close to zero as possible). They are very suitable for sorting parts, but they are not a substitute for higher quality measuring equipment. I also hope to see a version that supports the original developer.

I also have this tester design, and I must say that it is definitely worth about $15 on eBay. However, it would be nice to have a more standard version, because I am not even sure how to enter the settings menu of this customized "efan" version.

Can this particular tester be updated to the latest "mainstream" firmware? I know that the display device differs between multiple different tester clones, some of which are not fully supported in the main firmware. Last time I checked, the main firmware did not support the '128×64' display on this tester, with an unusual driver chip, maybe now?

For this particular model, another thing I think is worth mentioning is the annoying position of the feet, where the buttons and test sockets are suspended in the air away from the support area of ​​the circuit board, and the entire tester seesaws back and forth during operation. zif socket/press the button. In fact, this is indeed an annoying design oversight.

Do you have feet? My board does not have such luxury. May have been cancelled as a cost-cutting measure.

I stuck it with some cheap port freight rubber grommets and the problem disappeared.

Can I get a link to the exact model you have?

This is my exact link:

However, when I purchased it a few weeks ago, its inventory was already used for main shipment.

The order has been placed! I have a parts tray dating back to the 1970s with forgotten part IDs and pinouts. This thing will pay for itself within an hour.

My first one failed, so I had to buy a new one.

The flat ribbon connector of the monitor will eventually break due to bending stress, so if this is not the case, please don't mess it up.

Let me say it again: don't choose if there is no case. The flexible cable will break within a few weeks. Spend extra money on a protective sleeve version that protects the display cable.

I used a laser cutter to cut a box from acrylic. If anyone is interested, I can post a link to the file to respond to this comment. (Need to enter the space to get/convert them-it takes several hours.)

This unit is very useful. It can detect the "type" of the device and display useful information such as the effective capacitance of the diode, the beta of the transistor, etc. It can even find out which clues are (E, B, C).

I made a set of alligator clips connected to the zif socket.

I recommend this as a good choice.

my situation:

try again. my situation:

If possible, I would really like to provide you with documents. I just ordered one, which will save time for my own design. Thank you!

This is a very cool gadget. What a pity is the construction of Chinese quality. I did go through the project page (at least briefly), but I couldn't find a reference to buy hardware. I did find the DIY version (

), the price is $15.49 USD.

All models I have seen have 2*16 character display or graphic LCD display. And 14-pin ZIF socket, or some form of three-pin connection.

I have this version

I like it very much. The accuracy is sufficient to meet my requirements, and I found myself using the surface mount pad on it to test the components.

It looks like the Fish8840 version. You can implement a mod to prevent it from unnecessarily discharging the battery when it is "off".

cool. I will look for it. Thank you!

This is a website where someone has tested this version.

I think I was on the same day, just the day before. I admit that everything else seems equivalent between the two different things Autobot, Red Paint and "DROK". Except for the absence of a battery clip somewhere in the assembly, it looks very sturdy and can effectively find those small things without having to extinguish it with a magnifying glass.

I have a model with a 2×16 character display. I installed it in a cheap plastic food container and used it when using solid gears (as opposed to vacuum tubes). This is mainly a quick way to check transistors or weird parts, I can't read the marks completely. It has been used for more than a year, even if the battery voltage drops to 8.2v, it can still work normally

Are you using in-circuit (no power) readings?


You did not mention your Zener tube or 2.5 Volt regulator.

I guess it is using Zener because it is made in China.

Can your firmware be updated (easily)?

How far is your current firmware from the current version?

Thank you!

It is great to see that the "Transistor Checker" also measures passive components.

Oh, have you tried inductors?

My version is Zener. There is an ISP header, so it can be programmed. However, the LCD backlight must be removed to solder the plug down. I haven't tried the coil yet-I need to find one in the parts box and try it!

You don't have to remove the backlight-the 6 pins next to the back of the crystal are also ISP connectors. All you have to do is to create a mirrored ISP connector to use them.

But in that case, you really need to work harder.

My understanding is that the external reference will not have much impact on the proper accuracy of the crystal version and key resistors because the internal calibration procedure will make appropriate compensation.

In other words, to run the self-test, short-circuit all three channels before starting the device. This will trigger a self-test of all the variants I have tried. Follow the instructions. It will perform some tests on the channel short circuit, and then ask you to remove the short circuit, perform some more tests, and finally, require an upper limit of> 100nF between channels 1 and 3. I didn't double check, but I was beautiful to make sure that all the versions I tried utilize options in the mainline firmware to store test results to calibrate the instrument.

Zener diodes are temperature-dependent, so calibration will not help.

For such a simple and cheap device, this is a surprising feature list. Will have to get one. Thanks for your comments, especially looking for the real author!

I have a question. Looking at the schematic, I can find out how it implements each measurement/test (except inductance). I know the only way to make a measurement is to add a capacitor and see at what frequency the resulting LC circuit oscillates. But there is no capacitor. Unless they somehow (by mistake) use the internal sample-and-hold capacitor on ATmega's ADC pin as the C part of the LC, and since this is so small, it may explain why it can't measure the size below 10uH; but This is just a crazy guess. Who can determine how the device measures inductance?

If there is a resistor in series with the device, when you change the voltage step, you can measure the current (through its voltage) flowing through the resistor over time. The capacitor jumps high and the attenuation is low, and the inductor rises low and grows exponentially.

Measure the exponential slope and reverse the timing formula to obtain the inductance.

The slope of the exponent is – ta da! exponentially.

PWalsh's answer is as follows-but you should definitely check the English "Doku" pdf in the original svn repository I linked. Section 5.4 explains the measurement of inductance and even includes graphs of multiple measurements (and related errors) made with various ATmega devices.

Thank you [PWalsh] and [Adam Fabio]. I don't think that increasing the current through a resistor is a feasible method because the time constant is usually very small. However, after some searching on SVN, I found the description. There is a comparator on one of the ATmega pins used for measurement, and a timer, which can measure with the required resolution. Now it makes sense, thank you both again!

It seems that it will take a long time to review this. These testers have been around for a long time.

I agree. Good cheap gadgets. But like shit. But this does come from China. Cheap land.

nonsense. My most expensive gear is made in China, and my moderately priced gear is designed and made in China.

If China is cheap land, it's not because they can or can do it. No one else can do anything cheap, at least not yet.

Yes, these things are cheap. You can ship them to you on eBay for less than $15. And, for less than $20, you can get a product that is very close to the original schematic. It has through-hole parts and a socketed MCU, which is easy to hack. Look for GM328 from EZM Electronics studio. For devices without a casing, the quality is not bad.

Your expensive equipment is "Made in China" for a reason. China can do very well (KZ is one of my favorite IEMs), but usually few people do.

Dude, it’s not where the difference is made! These things are low-cost, because someone figured out how to do the job by using cheap parts (such as atmega chips). The old test equipment relied on many individual components, which only increased production costs due to the large circuits and boxes. When software can be used instead of hardware to complete the work, it can be expected that prices will drop.

Adam, when you check official sources, is there a place to pre-build official kits or official kits? Browsing SVN and translated pages do not point to the official publisher. I hope to get one from them (or EEVblog supply chain), but if it doesn't exist, then chinese-ebay seems to be good enough to be added to my tool shelf.

I have a bunch of PNPs that could match some guitar effects, but they have been sitting there for several years. The price of $30 or even $50 that encouraged me to build some pedals is small.

I do hope to link to the official version in the article, but I have no such luck. The best place to ask is probably the EEVblog forum-[madires], where frequent visitors say he is one of the developers.

Do you need a curve tracer to match transistors? According to the instructions, this tool cannot help you. Nowadays, you'd better buy matched transistor pairs on the chip.

Except occasionally, I don’t think there is any other content. Look for the "GM328" version on eBay. It should have a green PCB, MCU with sockets and (mainly) through-hole components. My understanding is that it is very close to the original design.

I haven't figured out how to order directly from Taobao, but the Chinese eBay sellers who sell these products have reasonable prices and fast delivery.

Hmm... "group buying", not "group buying"

This is also one of the cheapest ways to get an ESR tester-a girl's best friend when repairing electronic products.

When I decided that I could use avr for testing, I was fully armed with an AC test board and determined the basis of the transistor (NPN or PNP?), which quickly resulted in me only spending $8 (I have a text screen instead of graphics Screen) to get one of them. Great tool, I can read inductors and small capacitors that cannot be reached by the settings on the meter. It didn't tell me what pin is what transistor, there is no data in the world, but pointed out that I have a lot of JFETS and to-92 SCR (talking becomes dizzy!).

This is much cheaper than making your own open source software. It is very interesting to clean the hard-to-identify parts in the trash can. I went through my TO-3 and found that 40% of it was just scrap metal.

Please note that if it enters "calibration mode", it is because you have a "direct short circuit" between all 3 pins (it burns TO-3 every time)

It is recommended to make a wall power adapter for it!

(Is this a "22" ceramic 22pf of 200pf?)

Regarding open source topics, I have been looking for a copy of the AVR code to load into the Atmel 328, and I have a lot on hand. I have not been able to find a good working copy to burn. $8 is definitely cheap enough, just buy one. Just want to know, if I have, plug the chip into the Arduino and see if the files will be transferred to my laptop. I have been studying schematics and thinking about building a prototype on only a prototype board to see if I can make it work.

A few years ago, when I bought BK Precision's circuit transistor tester at a real estate auction, I had no market for transistor testers. However, it is great to see kits or self-made projects for other test equipment.

Yes, I own one of BK's transistor checkers and bought it at auction for $10.

The 2 testers I have are not from China:


The Simpsons are very simple, but the leader has a lot of chips, starting in the 1980s and even earlier. It can automatically identify bipolar and FET, and perform some other simple tests. But they all have charms; in "Death within a week," eBay miraculously missed...

Simpson 260 reminds me of the college days in the 70s. The transistor tester is an optional module.

Wow! The analog multimeter is still on sale.

Yes, its price is only $330

. This is 16 times that of the testers in question. I am sure that Simpson may be able to pass it to your grandchildren (my father has a Simpson multimeter, he occasionally uses it for car inspections, and it works), but it is apples and oranges.

I don't want to be a troll, I just want to know what the price is and want to publish it.

I really appreciate this tester. A long time ago, when I joined the local microcontroller club, I would recommend this device to people. This is an old version with a 2x16LCD. Its manufacturing cost is definitely much higher than the current eBay price, but it is the best choice for a multimeter.

It definitely arouses my interest...I have tried to design something like this, called TPIder (three-pin identifier)...I put in a lot of work, but it didn't go too far. I am glad to see the possibility!

So, wait, have I correctly understood that this thing can actually identify the pin? Just like you can plug in any three-pin transistor/FET/plug in any orientation, will it provide you with polarity, pin assignments (and more)?


A very simple double junction transistor checker, requires PIC10F202 or AtTiny13a (both source codes are available in


Details (French)

The checker only tells whether the transistor is normal and whether it is PNP or NPN.

Blinking green LED lights up NPN transistor

Blinking red LED good PNP particle separator

Hmm...very high usability and ease of use, but poor build quality and update capabilities. This looks like Adafruit's work or work that needs improvement. I think people will spend some extra money to buy some useful things, but these things are not ready and not available as tool kits.

HF also has its multi-meters, which can test inductors, semiconductors, etc. (and the price is much cheaper), but I did not use them for the accuracy of these capabilities.

It turns out that for less than $30, EBay has a large number of such products-although there is no firmware upgradeability...

I should probably get off the car, end a video, and start comparing the three different versions of the device.

However, at the same time, I learned that most of the versions on eBay come from about 3 different small electronic equipment companies in China. Adam identified one of them, "91Make", but there are Fish8840 and EZM Electronics studios. They all provide bare metal versions like this, and in the case of "finished" models.

They have not released firmware updates, nor have they released the source of their firmware versions. Fish8840 and 91Make seem to have made quite extensive changes to the mainline firmware of the graphic display. EZM seems to be very close to the main line. Fortunately, by changing some configuration options in the makefile and recompiling, people have successfully obtained the latest versions of all three manufacturers to use the mainline firmware. Detailed information is in this thread in EEVBlog, starting from page 54 or so.

I think the 91Make version does the best in terms of output on the graphic display. There are many problems with the Fish8840 version. I think that the graphics of various transistors are too heavy and difficult to read, and the design of the power supply section is a bit silly, resulting in wasted battery when "off". (There is a video on how to fix it, the fix may even record the mainline firmware in the document).

The EZM Electronics Studio version is probably my favorite version because out of the box, it supports all the options in the mainline firmware, and because it uses a socketed MCU and (mostly) through-hole components with appropriate tolerances. The downside is that because it uses the mainline firmware, the use of its graphic display is not so complete, and the SMD device test board may be the most inflexible of the three designs.

The electronic version of EZM is usually listed using "GM328" in the title on ebay, and the MCU with slot and through-hole components are obvious in the product photos of this version with graphic display, but for the version with two versions The display is very fuzzy line text display. They recently released an SMD version, which may be listed as GM328A. Their "finished" version in the enclosure is usually labeled "MK-328" and comes with three leads/test clips and a module with ZIF sockets and SMD test pads.

I would be very surprised if the firmware cannot be updated from the final version of EZM or any other manufacturer.

The firmware/hardware/documentation of Fish8840 version can be found here-

What a coincidence! I have ordered this version and will be assembled today:

This part uses high-quality parts: TL431AA precision voltage reference, professional PCB with good layout, electroplating and silk screen, and all parts are through holes, easy to assemble. I will also connect the ISP connector to upgrade the firmware.

The documentation in the SVN repository is excellent, with a very thorough accuracy comparison with professional measuring instruments. Cheap, useful, well-made and easy to crack-check all the boxes!

Does anyone offer a link to purchase pre-assembled with 2.5V precision reference?

When I put a Darlington transistor on the V2.07 software, it gave the correct forward voltage of 1.13 volts, but only said "PNP", I think it should say "PNP Darlington" or abbreviation. For BD648 (unused), Hfe of 44 seems a bit low, but I realize that the test current may not be enough to support the power transistor.

Now, I want to return to this page and read more, but the page has used up 3.246 megabytes of mobile data. In New Zealand, mobile data is very expensive. Data used to last for a long time at a slow 54k speed, but it is still There is no super fast internet. Websites due to lack of data (I call obesity websites)

Unused (TO22 case) SCR BT151, shown as NPN cathode (emitter) anode (gate), gate (base)

hFE = 0, Uf = 0 mV

I have designed a case suitable for 3D printing for the case of the device. If you don't have a printer yourself, you can order 3D printing in several places.

How difficult will it be to replace the Zener diode with a 2.5v reference voltage?

Use the originally designed lt1004? It may not be difficult at all (unless the Zener tube is buried by other things.) Just untie the Zener tube, and then solder lt1004 in the proper position (get one of the through-hole models, and then only solder the foot Just go to the pad.)

It shows that it only uses 2 pins, even though the to-92 version has 3 pins, and the 8-pin version has 2 pins. )

If you have a cheaper (perhaps less precise) product than LM431,

), you need to make a small daughter board because it requires several passive components.

In fact, one of the manufacturers only needs to tie the cathode and refV pins together to use the LM431 (cathode, anode and refV pins) without any passive components. see

Sorry, this thread came back from the dead, but I just learned about these great little testers. I am an electronics enthusiast (not EE), but these are very helpful for identifying the components in the parts box. Despite reading the comments here and on EEVBlog, it is difficult to track what it is. Can I use specific models or keywords to find the latest/(agreed) best version purchased on Aliexpress, Banggood, eBay, etc.? Thank you.

I am also very interested in current suggestions! The idea of ​​rejuvenating the thread again!

I want to transcode the encoding. do you have?

I have been for a while. They work very well, which means that the price is so low.

The power of my computer is broken. I removed 4 1000uf electrolytic capacitors and checked them with this small tool. All 4 of them are shown as diodes in some way. I went back to eBay and found a unit with the same appearance. The description says that the capacitance range is 25pf -100,000 uf, so 1000uf is covered.

Is there a problem with my meter? Or are all four caps broken at the same time?

Use the test cap carefully. Before connecting, you must discharge them by shorting their leads, because the stored energy surge will blow them up. There is also discussion in the EEVblog thread about setting up the protection circuit, but I don't remember which page of the thread.

You may want to try some other known good components to verify whether your tester is still spared.

When testing inductors below 1000uH, I am not satisfied with its performance. There is also a project for precision LC meters. Unfortunately, the transistor tester did not borrow anything from it.

Can you link to this project?

For anyone who wants to know which version to use, I have limited experience. I was and still confused about all the versions out there.

I just prepared a version for myself, which is obviously called the AY-AT kit (although you can't find a version with this keyword on the store site and it is not called in the official manual).

There are two (as far as I know) versions of the kit (already mentioned in the official manual and can be seen on the shop floor), one version has a 128×64 (controller ST7565) display, and a newer version With 160×128 color display (controller ST7735). ). I got a 160×128 color monitor. This is a great comment link:

It includes a link:

The current official manual (link to the repository mentioned in the comments):

Forum mentioned in the comments):

Why use the kit:

The device uses 99% through-hole components, and these SMDs have been soldered to the PCB. If required, it is easier to modify than the version with SMD components.


Show carefully. The display is connected to the display module PCB by only 2 flat cables. If you turn the display over, it will hang on the flat cable and it will be easily cut. Tape the display to the display PCB immediately, after which you can do some more permanent things, such as hot glue or the actual packaging box or others. I know this. I still flipped the monitor before applying the tape, but luckily the cable was ok.

Someone has scratched a scratch on the PCB, the scratch has cut a trace, and the device is not working properly, so before soldering, please check whether there is a scratch on the PCB and test the trace for any doubt.


Easy to assemble, easy to modify, the beautiful display has a voltage reference (TL431) instead of a Zener diode, but obviously it is not a good voltage reference, so it may need to be replaced.


The precision resistors R1 to R6 (in the official manual, R9 to R14 in the linked comments) (680 and 470K respectively, 3 times each type) are not very precise. I will replace them with real precision resistors.

This version comes with quite old software 1.12k. The official software version is 1.27. Although it means that I will lose the temperature sensor and IR test, I will update it as soon as possible, but at least I will get new part tests and servo tests.

The MCU programming pins have not yet been placed on the PCB, so I have to figure out, put some kind of wires and connectors, or just remove the MCU from the socket and program it separately.

As mentioned earlier, the monitor is just hanging on a flat cable, which is not good.

TL431 is obviously not a good reference voltage (2.5V). Alternatives are recommended in forums LM285 or LM4040 or other forums. I need to investigate.

The voltage regulator (7550) may not be very good either. I need to investigate.

The frequency terminal is not buffered.


As mentioned in the official manual, the color display is not very fast, but it is fast enough for me. Color is useless.

Since there are various connectors on each edge of the PCB, it is a big challenge to design a housing to include the battery, not just make the entire assembly taller.

SMD pad number is wrong. 1 == TP1, 2 == TP3 and 3 == TP2.

The kit I got is not equipped with capacitors for self-checking, but I have a lot of parts, so this is not a problem for me. Maybe other sellers include one.

Anyway, this is just my opinion, I just understood this, but I definitely don't fully understand the other versions, so please decide for yourself. I like this version because I can make it better/easier. Check the different versions in the official manual, although the difference between the two is not simple.

good luck.

I followed this topic and have not answered my question several times. Does this tester check the components in the circuit? ? ? ? ? ?

Thank you! ! ! ! !

Basically yes, if you connect the wire to the test point, but what you actually want to test is the overall effect of the circuit, not the overall effect of the components. Just like you can test a single resistor in a circuit, but if you have parallel resistors (and the parallel resistors may not only be actual resistors), it will show the combined effect of the resistors. The tester cannot electrically isolate the components from the circuit.

Like I have this component, I want to figure it out. When I used a multimeter to measure online, it gave me different results from when I removed it.

If you know what the complete circuit will produce, then it can be used to test faulty components.

I ran into a problem on the Sonoff board where the voltage regulator on the board heated up (in this case, enough to make a nice crater.) I had to start cutting one trace at a time to isolate the resistor, diode, Zener diode and transformer, look at it almost dying (it turned out to be a Zener diode. I replaced it, jumped across the cut marks, and now it works fine. What's interesting is that even if all the power comes, the regulator does During heating) output from the output voltage of 3.3V. I did not test it under 110V AC voltage, although I still used it when I noticed that it was very hot. )

It would be great if you can test in the appropriate place and be able to determine whether the part meets the specifications, but in this case, I can only know the regulator by comparing the initial reading with a good quality board The "4ohm" reading on the screen exceeded the expected specification, and then began to cut the part until it returned to the expected level.

TL; DR number

As jii said, it will test the parallel/serial combination of the component under test and other components in the circuit. Therefore, it will not bring you a meaningful test.

The ESR measurement value it provides for the capacitor is meaningless, because unlike the online ESR meter, it will far exceed the voltage above 600mV, which will open the semiconductor junction.

I have the V1.10 (2016?) version of this component test board, which has a rotary button dial on the lower left side, and is placed in the kit. Does anyone own the BOM or where are these 29 resistors? They are screen printed, but there is no value on the board.

true? Mine have value, but they are under resistance. Does the wording similar to 2578AY-AT appear next to the dial (very small, located on the right edge of the dial)?

No, that is the AY-AT version, the battery input is at the bottom? I did get a schematic of my circuit board (battery input on the right) from the seller in an e-mail with all components (for example, R1 10K) marked in the e-mail. It should have been included in the list, but it is not.

The first thing to try is to find AliExpress, bangood or other sellers you have bought anywhere. The image is small, but you should be able to see the correct value. If not, please ask for more help.

Interestingly, this thing almost never correctly recognizes J201 jfet (I have several products from different manufacturers), and 90% of the time it recognizes them as transistors.

Maybe a firmware update is needed?

Can anyone guide me how to use it to measure frequency? How to use it as a signal generator?

Thank you.

Great article, you can write an article on how to update the firmware of these meters to the latest. Thank you

"Update" is not a simple project IMHO!

For big pictures, there are new perversions... Oh, I mean, PERMUTATIONS :-) is still developing beyond the one depicted in this article in 2015. I recently (12/2020) bought 2 from different suppliers, it looks a lot like the one here, but replaced the two small diodes with 2 resistors (the drop voltage of the LCD display)...maybe others I haven't noticed the changes. They work very well, there is no M-Tester that provides manufacturer or version information. I did not test all features. They come with a "lock bit setting", so if you refresh the new code, you cannot restore it because you cannot read the code. No step back!

This is a recent tree showing the species supported by the community: each directory has a Makefile, which mainly deals with differences, so the code is #ifdefs's mouse nest!

PS I: \jays_lcr_t4\trunk> tree

Folder PATH list

Volume serial number is 8003-EDED










├─── Department















good luck!

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