Microcontroller based curve tracer

Electronic Curve tracer for measure and compare components on circuit boards

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This project was based on the Huntron Trackers. I could not afford to buy one, so I developed my own ones and built them.

What is it good for?

It is good for compare a working and a not working circuit board, without you have to apply any power to it. A curve tracer show Voltage - Current characteristic of any electric component, like diodes, capacitors, CMOS ICs and many more, which you want to look.

This equipment mostly used in repair purposes

I created three version of the tracker, called Version 1 , Version 2 and te most recent one is Version 3. SUF joined the development, and he is currently designing and testing a new version which will be the Version 4. Below this lets see how each version works.

Version 1

I started develop this version around 2017, when I saw a Huntron tracker at my work and I thought it is not too difficult electronic, but so overprice at the same time.

The Version 1 has just one voltage and one frequency range, so it is a very basic model. The basic idea behind a curve tracer a simple circuit, which input is a sine wave and has some resistor in it. We need a current limit resistor and a current sense resistor.

The other big part is a dual channel oscilloscope with X-Y mode, or like my version I used a cheap arduino pro mini and a display, it is more then enough for a basic operation. I added a function, with the tracker can save a curve on the display and can measure an other component at the same time, so with that you can compare a good component with a bad component.

Tracker Version 1

The schematic is a updated version, with some compensation, and modification on it, I could reduce the short circuit difference, so the line is almost vertical on the screen, when the two probe is shorted.

The upper op-amp is the voltage sense (X axis on the screen), the lower op-amp is sensing the current, which is flowing through the measured component (Y axis on the screen).

Some picture about the Version 1

Tracker Version 1

Tracker Version 1

It is not too pretty, but it works well, for a beginner I recommend to start with this, because it is cheap, and after easier to improve. 

Version 2

The second version is basically a much closer producte what I really wanted to create, it is based on the Version 1, but I learned a lot from my mistakes. I wanted a multi range and pc compatible version with the stand alone usability without pc, so most of the time I can use it like a independent device, but if I have to I can save the curves to the pc as well. The development was long, it took me more than half a year, and a lot of money as well. I think it is worth all the time I puted in it.

Lets start show what I am talking about.

Tracker Version 2It has 25 voltage range, 5 resistance and 6 frequancy range. The screen is a 4" mcufriends tft touch screen, but in this operation I did not put any function on the touch screen. The Version 2 has two channel, it is more easier to compare curves at the same time.

The buttons light up when the actual function selected.

This device is much more complicated then the first version was, so I do not recommand a beginner to try to build this.

More info about this version you can find below at the log section.

Version 3

I started developing a new version after a couple months the Version 2 was finnished. This will be similar to the Tektronix TR210. It is basically the Version 2 without the screen and any pc connection option. For this version you need a dual channel oscilloscope, but I think it is not a problem for that who is looking these types of instruments. This version also open source, so everyone can modifie and develop it.

Version 3  have 6 voltage ranges, 6 resistance and 3 frequancy ranges, it also capable to measure two channel alternatly.

You can find the documentation at the download section.

A bit of explanation what the circuit will do. The arduino pro mini at the left acting as a Digital - Analog converter, so it is generating sine wave at variable frequency ranges. Next the signal is going to a digital potentiometer,...

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  • Curve Tracer V5

    Máté Tóth06/15/2021 at 18:07 0 comments

    The time is here, although this is just an early prototype:

    A little while now I have started working on a new version of the original Curve Tracer series. Based on most of the feedbacks, everyone wanted to build the Curve Tracer V2, but because of the not so great documentation from my side it was not so easy.

    In the mean time I have managed to upgare my little home lab and right away started designing a better version of the original Version 2. 

    My main goals was to improve the screen size with adding touch functions. Most of the mechanical designes are done as far as the front panel. The Version 5 has a 7" lcd with touch, which improves the look of the instrument.

    I know not everyone likes touch functions, so I aslo added a keyboard woth an encoder wheel.

    This is my first PCB which I have ever finnished from designe to manufacturing. :D

    The analog part is still under development and in designe phase, but there will be not really new stuff in it since SUF and I managed to develop 4 previous versions of Curve Tracers.

    The software also in very early stage so please not expect to much from it on the below video.

    For the end please watch a little demo of the early demo of the Version 5 Curve Tracer:

  • Current state in pictures

    SUF10/02/2018 at 06:38 0 comments

    There are many things happened since my last real project log.

    In the V4 almost all of the controls are working with PC control: -frequency, amplitude, current control resistance, DUT switching and alternating.

    The only thing left until the equipment start to work as expected is the measure amplifier control. On the other side I've long road ahead.

    The planed roadmap (without dates):

    - Measure Amp (milesetone, the equipment works with external XY oscilloscope)

    - ADC control software

    - Measurement display on PC

    - Add SS1963 based 5" display

    - LAN board

    - USB Flash

    - SD card

    - Finalized MCU board

    - Front panel control test

    - Front panel board design

    Until those, here are few pics made during the development:

    Arrived boards:

    Finished PSU:

    The PSU measured output voltages:

    Power Amplifier built:

    Almost all of the analog electronics + the MCU dev board:

    Mesaure the phase shifting of a 22uF bipolar electrolytic capacitor:

  • Repository

    SUF09/26/2018 at 07:46 0 comments

    It is just a quick note. I made the source control repository publicly available. You can find it here:

    Please be aware. The hardware designs, firmware source, PC software source is under heavy development. Every commit goes to the master branch. No reason to switch to any kind of branching model (gitflow for example) yet.

    Please do not use the repo for building the instrument. It WILL NOT WORK!!!

    The repository is there for two purposes:

    1. Support our development effort.

    2. Give some outlook about what we want to achieve.

  • Fake in China

    SUF09/13/2018 at 20:23 0 comments

    I'm continuously working on this Curve Tracer in my spare time. I designed a Vishay VO14642 photovoltaic SSR into the circuit. It is quite a nice, but pricey device.

    I thought why not try to order it from Aliexpress. For control I also ordered a few from Mouser.

    Both devices on the same board:

    The original on the left

    The fake measured

    The original measured

    This device should have 0,25 Ohm maximum on resistance. 

  • Boards, MCU change

    SUF08/21/2018 at 21:25 0 comments

    This log is intend to be a small status update without deep explanation of circuit or software description.

    1. I've finished the PCB design all of the three analog boards together with the PSU. Here are the pictures of the board designs:

     2. The schematics are changed a bit according to the board routing and some component availability. I uploaded the updated schematics to the files section (not too much changed)

    3. All of the boards ordered from JLCPCB. I'm expecting to get them until end of tomorrow.

    4. All of the components ordered from various sources: Lomex (local), HQElectronics (local), Mouser. Unfortunately I had some misunderstanding with Mouser about my companies status, therefore they canceled the order of the TI opamps. So I finally ordered the opamps directly from TI. Hopefully I'll get everything by beginning of the next week

    5. I had not too much lack with the selected MCU.

    First I tried to use Arduino for the programming. The STM32DUINO is almost unusable when you want to do something deeper hardware related. Running the Timer-DMA-DAC as a sine wave generator was unsuccessful. After a few days struggling, switched to CubeMX + Atollic TrueStudio. With this environment, it started to work almost instantly. After this I tried to put together the USB-CDC communication unsuccessfully. After many tries, also involving other development boards, it become clear, that the USB code generation of the CubeMX for F3 simply doesn't work (we will see if any suggestions come:

    So I switched the project to F4, to be precise to STM32F407VG. Actually I'm using the STM32F4-Discovery board for the development, what I already have for years.

    The sine wave generator works, I've some USB communication, I've the command interface for the components (the commands still not work via USB, but it is on the way).

    The plan actually, to build the first iteration of the V4 device, completely controllable through the USB port and using a PC software for all of the functions and display. The integrated LCD and controls will come in the second iteration.

  • Analog circuits

    SUF08/10/2018 at 13:25 0 comments

    I'm heavily working on the next version of the curve tracer. Today I almost finished the schematics of analog modules of the device. All of drawings are uploaded into the files section. Actually everything reside in a private repo on the GitLab. This will be publicly opened when I order the first revision PCBs. Until this time the whole circuit is so shaky that I don't want anyone to build it, because the design will probably heavily changed and there are incompatibilities exists between the schematic an PCB designs.

    About the circuitts

    Power supply module:

    The power supply use a enclosure mounted toroid transformer with two 14V secondary windings (probably a 100VA model). The circuit itself provide +-15V from linear regulators mainly for the analog circuits and the power amplifier, a +5V and +3.3V from buck converters for the logic circuits (plus MCU, Display, etc.). And a four channel buffered rail splitter (virtual ground) used for the level conversion of the ADC and DAC (probably two will be used, but it is easy to build four from a 4 channel opamp)

    Power Amplifier module:

    It converts the 0.65V-2.65V swing sine wave from the MCUs DAC module to +-10V (20Vpp) gound referenced load capable signal.

    In the input I put a unity gain differential amplifier. This will convert the input to -+1V by substracting the 1.65V reference DC from the power supply.

    The next stage is a 1.28x gain non-inverting amplifier creating 2.56Vpp signal. This signal attenuated by a 256 step digipot. This give us 10mV step control of the power amplifier. The power amp has a 10x gain. So the result: we can control the output voltage of the amp 0-20V in 100mV steps.

    Attenuator module:

    This module control the current limiting resistors on the output of the Power Amplifier. As requirement we can't use conventional mechanical relays mostly because of the noise it makes. Therefore I choose three different kind of solutions to set the current limiting resistor value (we need AC capable devices):

    1. Low current version: ADG451 (or ADG441) and ADG1411 analog switches (capable around 100mA)

    2. Medium current version: Vishay VO14642 photovoltaic AC MOSFET SSR (capable 1A AC)

    3. Load switching: Si8751 isolated MOSFET drivers + dual MOSFETs (capable 4.5A AC)

    Also this circuit provide the TVS protected output for the DUT and the measurement point for the output current and voltage. The output current measured across the whole resistor network and not on an additional current sense resistor. This solution probably generate less noise, but on the other side more sensitive to the temperature drift of the resistor (we will see, how this works in practice)

    Measurement Amplifier:

    This is a two channel amplifier one for the current, and one for the voltage. The input signals are buffered with two unity gain amplifiers. The voltage signal is coming from the voltage across the DUT and amplified by a "PGA" capable of creating x0.1, x1, x10, x100 and x1000 gain respectively. The current signal is comming from the voltage across the current limiting resistor. As this is not ground referenced I used a differential amplifier configuration with x0.1, x1 and x10 gain.

    The outputs of this circuit can be directly connected to the oscilloscope X and Y inputs and will be also connected to the MCUs 12bit ADC through a level shifter (not implemented on this board) 

    This is all for now. More to come.

    If you have any question, suggestion on this design, please let me know in the comments

  • MCU Selection

    SUF07/31/2018 at 19:03 0 comments

    As I mentioned earlier I wanted to change the two AVR MCUs from the original design to a single 32bit one.

    Here are my selection criteria:

    • Two at least 12bit DAC channel - One channel is used for the sine wave generation, the second maybe used for the pulse generation (not designed, decided yet, but better if it is available)
    • Two at least 12bit ADC channel - For measuring current and voltage on the DUT. If parallel sampling and/or differential input available is good but not requirement
    • DMA for DAC operation
    • 32 bit core - ARM Cortex-Mx prefered
    • Arduino framework support, free, native C/C++ IDE support (I haven't decided between the two, so the support is necessary)
    • Low cost development board
    • Easily solderable (for me. Means: TQFP accepted, QFN, BGA not - I know this is my personal limitation, but I don't want to learn it right now)

    Based on the specs above my choice is an STM32F303RET6:

    And the development board for it:

    I ordered the board from Farnell yesterday. Today arrived:

    Next: seting up the development environment

  • V4 Anouncement, new member

    SUF07/29/2018 at 15:34 0 comments

    Hi Everyone,

    My name is Zoltan Gomori (SUF). I recently joined the project to speed up the development.

    I started to develop the new V4 version of our curve tracer. Here is what you can expect:

    Now, I'd like to summarize a few design concept for the project.

    I started to work from the 3rd version. As I see now, It can be called as the 4th version because it will have so much differences.

    1. Modular design. I want to be able to use the design either with internal display or with an oscilloscope
    2. Use one 32 bit MCU instead of the current two 8 bit AVR (most probably an STM32)
    3. Internal power supply
    4. Based on the Huntron Tracker 3200S specification - except the 128bit scanning interface
    5. Complettely elliminate mechanical relays (even the reed ones)
    6. Get rid of the most of the digital potentiometers - not really fits for the needs, using resistors and analog MOSFET switches instead
    7. Get rid of the discrete R-2R DAC using an MCU integrated instead
    8. Utilize MCU integrated ADC/DAC/DMA as much as I can
    9. Get rid of the trimpots as I can (probably need to keep it for some offset setting functions)
    10. Keeping the error of the equipment around 1% every place (it is not a high precision equipment. If we want to decrease the error significantly, it cause significant rise in the costs)
    11. Adding the pulse generator as an optional module. It was missing from the 3rd version
    12. Adding the lower current limiting resistor ranges (down to 10 ohms)

    First of all, I made a block diagram of the equipment:

  • Files for Trackers

    Máté Tóth04/08/2018 at 19:08 0 comments

    Dear all,

    I uploaded all of the latest drawings and ino (arduino) files for all 3 version.

    You can find in the "File" section, and you can download those.

  • Version 3 is done!

    Máté Tóth03/18/2018 at 17:07 1 comment

    I finnished the Version 3 prototype, every function is working now. I found tested some future development on it, and I managed to connect it to the PC, so will be also capable of saving curves onto an excel sheat. I need some time and I will finnish the configuration on this also.

    Here is a video about every function:

    Some picture:

    Curve Tracer Version 3
    Curve Tracer Version 3
    Curve Tracer Version 3
    Curve Tracer Version 3
    Curve Tracer Version 3
    Curve Tracer Version 3
    Curve Tracer Version 3
    Curve Tarcer Version 3
    Curve Tracer Version 3

    I am quite happy about the prototype, I think it is better then what I expected when I started. Now I have the final circuit so I am looking forfard to designing my own pcb for it. 

    It still missing the power plug at the end, but I will place it.

View all 24 project logs

Enjoy this project?



nicolas Jonasson wrote 06/20/2020 at 20:12 point

Is this project dead?

I hope not...

  Are you sure? yes | no

Máté Tóth wrote 06/21/2020 at 08:02 point

This project is in the parking spot for a while, not enough motivation from my side to keep it going. I have ideas to make this more easier to build, but I think need some help with the new designe and help to fix some known bug.

  Are you sure? yes | no

dgourlay wrote 11/14/2020 at 20:24 point

always good for your followers to remember... "at your pace, on your schedule" 

Good luck in the future with your work.


  Are you sure? yes | no

eduardo ruiz wrote 06/08/2020 at 03:47 point

I would be grateful if you could help me. The image appears backwards, mirror effect, could it be?

  Are you sure? yes | no

BEKİR wrote 04/25/2020 at 22:33 point


Your project is very nice.

I want to make version 2. Can you help me? Could you share more details. My mail:

Thank you in advance.

  Are you sure? yes | no

samanyolu_gs1 wrote 03/29/2020 at 07:38 point


In the photos, I see the cable at the A15 end and it is not in this diagram. I will install the circuit, but is there any other missing?

  Are you sure? yes | no

samanyolu_gs1 wrote 03/22/2020 at 21:36 point


Your project is very nice.
  What does the Button and LEDs mean in the Tracker V3. So Button 1 A channel Is Button 2 A / B channel?
- Led 1 = A channel, Led 2 A / B?
- Which trimpot is used to switch between channels A and B?
- Are the buttons Pull down? Pull Up?

When I installed a program in Proteusta Megaya to try only the buttons, I could not operate the buttons as in the videos.

Thank you. Sorry for the bad English.

  Are you sure? yes | no

Máté Tóth wrote 03/23/2020 at 11:23 point

Button A mean A channel is selected. Button B is B channel is selected and button A/B mean it is in alternating mode between the two channel. With the potentiometer in A/B mode can be selected, how fast switch between the two. 

-The buttons pulled down.

-If you have still problem with the program, please send me a screen shot, in DM.

  Are you sure? yes | no

samanyolu_gs1 wrote 03/15/2020 at 20:52 point

Hello, can I use LM358 instead of LT1013?

  Are you sure? yes | no

Máté Tóth wrote 03/16/2020 at 20:50 point

The LT1013 is a better opamp, but the lm358 could be used if it is easier

  Are you sure? yes | no

Soydaner wrote 03/04/2020 at 07:28 point


I think your project is quite successful. first of all congratulations! I'm interested in V3. I could not see some of the parts in the scheme in the V3 version in the prototype circuit. where are the digital potentiometers in the scheme? Is there an update in the scheme?
By the way, would it be a problem to use CD4016 integrated or similar instead of reed relay? Relay sound can disappear completely with integrated cd4016. have you tried a way like this? thanks in advance.
See you...

  Are you sure? yes | no

Máté Tóth wrote 03/16/2020 at 20:47 point


The CD4016 could be used, the reason i used reed relays, because it was easily accessible for me.

  Are you sure? yes | no

Hakan wrote 02/05/2020 at 18:21 point

Yorumların yarısı Türk çoğu bu projeyi yapıp para ile satmanın peşinde!!!

Half of the comments are Turkish, most of them are after doing this project and selling it with money !!!

  Are you sure? yes | no

Máté Tóth wrote 02/05/2020 at 19:30 point


I know that the lot of turkish men read this project, it never bothered me that some one making money of this. Personally I Never got any money about this project, but I did not made this for money, my goal was to try to show people it is an other way than Huntron expensive machine. I would be glad if, because of this project every shop could afforde this kind of machine. It could make Jobs faster and cheaper. 

  Are you sure? yes | no

Hakan wrote 02/05/2020 at 19:34 point

I was not expecting this answer I was surprised 😅 I am also interested in your project, I will do it soon.  I like your project, I look forward to updates.

  Are you sure? yes | no

dgourlay wrote 11/14/2020 at 20:23 point

This is sad news.... people scooping up your work for their profit.  One thing is to out do them.... do it better :)  I noticed that this project has been shelved.  Is your work on it... over?  Thanks - you're obviously a very talented fellow!

  Are you sure? yes | no

arieslaptop wrote 11/11/2019 at 08:29 point

Thank you so much for this project , i like this project , some feature you can add , most of them you had already build in your update

1. save and compare feature 

2. auto volt and frequency selection 

3. in pc version you can capture test pcb photo and pin to pin save curve like (fados7f1)

some of feature also can add with this similar project

  Are you sure? yes | no

unal_akdogan wrote 10/29/2019 at 11:19 point


asking for version 1. What does the button on the red probe do? The other end depends on where.

  Are you sure? yes | no

Máté Tóth wrote 11/05/2019 at 11:29 point

It can store one curve in memory and if you hit the button it store the actual curve on the screen, then you can measure some other point and compair it to the saved point.

  Are you sure? yes | no

alvaro henriques wrote 08/23/2019 at 15:28 point

Hi Máté,

Congrats, they are really a cool projects.

I would like to do the Ver2. Could you pls share more details about it (sch, components,...)? My e-mail address:

Thank you in advance.



  Are you sure? yes | no

eduardo ruiz wrote 06/23/2019 at 16:47 point

Al aire libre

  Are you sure? yes | no

eduardo ruiz wrote 06/23/2019 at 16:47 point

Al aire libre

  Are you sure? yes | no

vagner_xu wrote 03/23/2019 at 19:32 point

gostaria de montar a verção v1 vc poderia me mandar o que eu preciso só para v1 

funcionar no pc via usb ? por favor

  Are you sure? yes | no

vagner_xu wrote 03/23/2019 at 19:26 point

Detalhes gostaria de montar v1

  Are you sure? yes | no

feridunbilgin1993 wrote 02/05/2019 at 00:02 point

Hi, how many ampere transformers need to use for version 3, how many watts of energy is needed, thank you

  Are you sure? yes | no

feridunbilgin1993 wrote 12/06/2018 at 18:00 point

My Name is Feridun. I like to follow your projects, if you ask v3'in share detail with me,

  Are you sure? yes | no

SUF wrote 01/07/2019 at 18:33 point

all of the project files can be find in the gitlab repository

  Are you sure? yes | no

grantfullen wrote 09/24/2018 at 03:17 point

I am intrested in building the v4 as a kit. Let me know if you going to offer as a kit , or I can source all the components myself once you post the final files. Great Job............

  Are you sure? yes | no

SUF wrote 09/26/2018 at 07:07 point


The v4 is in the lab today. We are although it is OpenSource (I'll post the repo after this  answer), we are plan to sell it when finished. Complete unit for sure, panels, kits are under consideration. Please don't expect it shortly as still a long road ahead until the finished equipment. 

  Are you sure? yes | no

Marek wrote 07/08/2018 at 14:58 point


Could you give me schematic data and a list of components like display type etc Versions 2 ? 

Well thank you.

  Are you sure? yes | no

worrawit wrote 05/14/2018 at 02:13 point

Hi, Máté

I'm sorry.I'm not good English.

Thank you very much. For the document you uploaded.

What version of the board INO  do you use for the project Tracker_V2?

I use the board Arduino mega 2560.

Do not compile source code. Error  

tracker-V2_2017.04.10:157: error: 'REG_ADC_MR' was not declared in this scope

   REG_ADC_MR = (REG_ADC_MR & 0xFFF0FFFF) | 0x00020000;


tracker-V2_2017.04.10:162: error: 'DAC0' was not declared in this scope

   analogWrite(DAC0, 100 );


tracker-V2_2017.04.10:757: error: 'DAC0' was not declared in this scope

   analogWrite(DAC0, freqvalue );


Thanks! brother

  Are you sure? yes | no

Máté Tóth wrote 05/14/2018 at 04:08 point

I used Arduino Due, that why you have errors. Due has 16 bit adc an 2 Dac. 

That what the errors say.

  Are you sure? yes | no

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