I have made this unit, with all 9 episodes combined and LOVE this thing. Thank you VERY much for all your hard work. ( ps I'm in New Zealand). Cheers

Damn. i Miss this guy, i wonder what hes been up to.

How could anyone dislike this? It's the best diy electronic DC load on KZfaq. I always look forward to your videos. Keep up the good work.

happy i discovered your channel.one of the best if not the best dc load i've seen.well explained and implemented.

Am I the only one who watched this like an action movie? Very good project, very informative video. Thank you sir!

Another great video! I have been wanting to build a DC load for some time now, and your video has given me the inspiration to finally build one. Thanks, Greg C.

The best DIY Electronic Load video with lots of bells and whistles. Thank you very much.

This is how a product is designed and developed. Well explained with minute details.

Thank you. You put your heart and soul into these projects and videos. Ticks me off that people have the nerve to give a thumbs down.

Amazing, explained just perfectly, can't await to see all other parts.

Love your videos. Your projects not only are very useful but are also very good explained. I want you to know that your work is highly appreciated. Thank you for your effort.

What a superb. tutorial, a rare treat to find someone on KZfaq that actually knows their subject.

I have been watching a lot of your videos lately, and became an instant fan! It's very clear to me that you thoroughly enjoy this stuff. The care with which you plan out these videos, the time, thought and effort you put in to the projects, including the video production is truly commendable. There are dime a dozen channels on KZfaq, but none that I've seen do anything close to what you're doing here. Tip of the hat to you sir! Please do keep this up. Can't wait for part 2.

Nice to see you back again. I'm very interested in this project and will most likely build one myself. Merry Christmas.

You're back with another fantastic video! Very good content.

Brilliant and simple circuit. Thank you for sharing!

I'm subscribed to a lot of electronic hobby channels and I must say that you are the only one whose videos are informative for a guy who doesnt have big knowledge in electronics. Great Great videos!

Another outstanding project! Thank you so much !! Greetings from south America!!

Another excellent project and very well explained, as usual. Thanks and have a Merry Christmas and a Happy New Year.

Great project and as always, an excellent explanation. I look forward to the second part. Merry Christmas.

Brilliant. I know time has moved on but really, Wow I understood this , excellent teaching and demonstration. Thank you.

excellent project! your projects are complete and amazing

Absolutely perfect timing - - Santa did not get the load generator I had on my list so this will make a perfect project!

Nice project Louis. I'll share this with my ham radio club's Builders Group as several folks have expressed an interest in building their own electronic loads for their workbenches when we start up again in the spring.

WOW, Nice Christmas video. Excellent video, concise and great explanations. I do look forward to your videos. I plan on building this. I have been looking for a DC load project that had this same criteria that a novice like I could follow. Thank you for taking the time to share your knowledge!

This is an interesting project. Thanks a lot for your video's. I like your video's because you are showing the thinking behind the designing process of the project and not just the project itself. As far as this this particular project is concerned, it would be even more interesting if it could be turned int a version of which the CR function could be used as a load for low frequency AC signals, for instance as a test load for audio amplifiers, but that would, amongst other things, require measurements of negative voltages and currents as well.

This is a very good project! The 2 channel, 18 bit ADC sure offers a very good resolution for voltage and current measurement (perhaps overkill), and the 12 bit DAC is fine enough to provide control over the pass MOSFET. Three devices on the same I2C bus, and that's it! Love the simplicity.

This is great! an unexpected christmas gift, thank you!

What a phenomenal, video! I just found my new favorite channel !

Another nice project to look forward to. This is a useful device. A very educating video. Thank you.

Another great project - now one of my New Year's resolution to build :)

Adding a battery capacity test function with programmable cut-off voltage would make it even more universal.

Great Video, thank you for your efforts and importantly for sharing the design. I feel a construction project coming on... looking forward to part 2 Ric

Great stuff! You are very good in teaching!

Another amazing project ! thank you! :)

o my with the neat Arduino and the serial port you can even write test programs to control the load and bench power supply settings to test different customer devices automatically 🥳👌🧞‍♀ another super project 🌷🦤☕🧁 thanks a lot ♨ excellent description

Really excellent description and teaching methods.

This is awesome! I'm definitely translating this one and linking your video to my website.

Great project. Very clear explained. Thank you so much. Best wishes for 2017.

thats a great project i will be having a go at building this. Thanks for the information and a merry Christmas to u

Very glad to see this project. Think I will attempt to build your design project as well. Very good. Carry On!

Thank you, very interesting video! Can't wait for the part two! :)

I want to build one for my lab with the following chnages; I will connect the heat pad of the MOSFET directly onto the heat sink and place the insulator on the 0.01 Ohm resistor (if I had one), for better cooling of the FET? I have a few 0.001 Ohm 1W surface mounts on hand, which i intend to use, instead of the 0.01 Ohm you are using. I don't want to connect it to the heat sink, as it will add complexity in calculating the junction temperature of the FET, from the LM75 readings. Thanks for this practical project. Sick of all the LED blinking projects everyone else makes. You have excellent lab quality designs that are very reasonable to build, and above all, it's open source. Merry Christmas to you and all the people of Earth.

Looking very versatile Louis. I like the design goals. I did not see any precision voltage reference in the schematic. Adding one for the ADC and DAC stages might be worth investigating. Also a second PCB dedicated to the heatsink mounted components will help with current handling as well as making it easier to package the unit into different cases and use of different heatsinks. As a final wish, perhaps the ability to add more mosfet stages to increase the power handling. Low tempco sense resistors are expensive so your 35W unit looks to be a useful hack to avoid drift. Looking forward to the progress on this project.

Thanks for this entertaining and interesting video. I am looking forward for part 2.

Good project. Thanks for sharing + Happy New Year.

Looks like its going to be an interesting 2017 on the Scullcom Hobby electronics channel. Thanks

Almost done building mine. Outstanding PCB Louis! Just waiting on a few parts. Got all you sent in the mail today. I'll send you some pics when it's done. Thanks for a great project. This will replace my DC load I built from a guy down under. No support from him at all.

Best ever electronic tutorial

wonderful explanation ,always waiting for new upload

Dear Sir, Your accomplishing this while maintaining a home and raising three children is a marvelous achievement.I need to design similar constant current/ power Electronic Load for 500W.

It is the best tutorial about DC load.

Excellent project, thanks, love these tutorials, very clear and concise.... Would love to be able add some functionality for this to test batteries, and perhaps extract the data from the arduino to display graphs etc...... Loads of scope I reckon, looking forward to,part two! Time to dust off my pcb chemicals and and start making somethings!....

Very nice project and excelent class, thanks a lot for sharing

Thanks for that passion ....you are the man .

Two things to think about: * Since your current sense resistor is higher value and on same heatsink as power mosfet, fet will heat up resistor and its resistance will go up, you can see that on this video, where you had CR, current went down. maybe think about lower value resistor with x10 or something op amp. OR add function in software to compensate this live (but you may need to fix oscillations that you could get from adding this in software) * Also think about adding energy measurement, when you would like to know capacity of battery

Very nice explanation and design. Thanks for your time! Ewald

Neat project.. Thanks for the tutorial, I learned a few things..

Another very interesting project Louis. I think would be a good idea to use a differential measurement over the sensing resistor, this change will decrease the impact of the trace resistance, making the measurement more accurate.

Thank You for this projecct. I will build it when it will be in a mature state. On my whishlist is an "interface" which allows to read the main KPIs (ampare, voltage, time) to an external device (i.e. PC with a program like Matlab or similar). With that information a battery discharge curve could be displayed and it would be easy to test and compare differnet batteries and check if they provide the offered capacity.

As always, perfect explanation! . Looking forward on how this project will develop. Would be nice to test 18650's with it. Happy Christmas and a healthy 2017, thanks a LOT!

Wonderful project, well done sir

Nice project. A very good starting point for me. I need a DC load to test my own PCB design. I have some rotary encoders, an Arduino Pro Mini (without USB), some 2x16, 2x20 and one 2x24 LCD. the only thing missing is a usable FET - maybe I could salvage an appropriate one out of the many PC power supplies lying around here. I'll give that a try.

I have been following this tutorial from the beginning, this is a very interesting project and i really love your step by step approach of dealing with each problems, i am interested in the project and will like to purchase if it exist as a kit. thanks

thanks for sharing your knowledge.

I have started almost the exactly project about a half year ago, but i gave up with programming, i have the hardware laying in a box, soldered together as modules from China, I hope i can finish it, i will review my work based on your video, and hopefully finish it.

You may want to watch the dissipation on the MOSFET the one you've chosen looks to have a maximum of 70W. Thanks for the great videos.

You are a great teacher! Have you done any work with IGBTs? I saw it being used in a analogue DC load to handle very high currents.

Love the backdrop of keithley bench meters ... fine taste sir very fine taste

Great video. Very educational.

Very nice project. Thanks a lot.

A couple of things come to mind. I'd have gone for a MOSFET in the bigger TO-247 case rather than in TO-220. Also, you might want to put a bend in the leads of the devices that are mounted to the heatsink, which will flex them slightly as temperatures change. Leaving them straight will eventually pull them out of the device packages. I know of one manufacturer that got into trouble with this. :-) Also, I see that you started out with 3 wires on that fan, presumably the 3rd wire being what some computer motherboards use to show me the speed that the fan is running at. This would be useful to monitor that the fan is indeed running, and you could have the software do a shutdown if that signal were absent. In the case of either the fan or the MOSFET, you could allow for both footprints on the board, so one could use whichever device was handy.

nice project! I was wondering when you we're going to publish something on this subject :-)

Thank you for this great video! Just in case some arduino gpios need to be saved for other purposes: using only one analogue input together with some resistors on the buttons would laos do the job, and probably would also ease the wiring. I'd also use separate wires to measure the output voltage to avoid the voltage drops...

You should swap linear region and saturation region on your board at the beginning of video. Saturation region is used for switching, when drain to source voltage is at minimum, so power dissipation at the transistor is low. All linear power supplies and electronic loads use linear region of the transistor, so DS has some voltage drop, and as a result of it we shall provide heat dissipation.

Fantastic, Nice project!!!!

Very nice year-end project sir :). How I wished I can make one myself. Unfortunately I can't because I can't source out those SMD parts here in my place. 'Cause I'm living in a place very far from the city. Hats off to you sir. Again you make another quality project.

I used op-amp ADA4522-4 instead AD8630 but I have to connect the op-amp V+ rail to 12V because voltage follower U7A cannot reach +5V on pin1 and between 4V to 5V behave strange. Many thanks for your project. It's well explained. I manage it, at version 1.

Nice project. You could implement some acceleration detection in the rotary encoder so you don't need the cursos. The amount increased/decreased is defined by the speed of rotation.

Thanks again for making these videos...PEACE

Thanks for sharing with us this nice project. I have few ideas to improve it: 1. using 3 pin fan to control the speed will fix the nois from fan in most cases :) 2. Improve the LCD text arrangement. Right now one row is used for indicating on and off state of the current source. Imho better idea is to add external LED to indicate that. 3. Increasing the maximum voltage support :) Niki

Excellent. Thanks

Great job! Thanks! :)

I am a software guy, it helps me a lot.

nice project also ... student and hobbyist made happy.

Yes it is a great proyect.

awesome project

very nice job!

I have designed a somewhat similar project. It also used an Arduino Nano. I like your hardware design better than my somewhat simpler version (I used the Arduino A/D inputs instead of separate A/D's, and I did no temperature monitoring). One thing that I did that on my project was to use a PC application that communicated with the Arduino over the USB Virtual Serial port, both for parameter setting and display. This allowed me to add real-time charting and the ability to log data to a CSV file for archival/data logging purposes. Automated testing is practical, and something like MPP is easy to calculate. Another implication is that the Arduino code only needed to deal with raw data associated with setting current and associated control functions and the PC software could do other calculations needed. I appreciate the flexibility that a PC application provides -- I can add software and UI features without having to go through the, somewhat painful (at times), Arduino code/debug/test cycle. All of the PC code was done using the free Microsoft Visual Studio Express edition, so there was no extra cost for that part of the project. If you have any interest in collaborating, by having me write a PC display application, I'd be happy to hear from you (www.hardandsoftware.net). The initial application would be display and data logging only, but control code could be added fairly simply. I'd start with display only, because the Arduino code changes would be trivial.

Top work

Excellent. Thank you.

Nice initiative for a product that most of the peoples are in need of. Please do an extensive testing video where you could show the dynamic performance of this load on CP and CR modes when voltage changes rapidly. Also low voltage performance testing is needed. Say for example, someone wants to test a battery discharge performance of a 1.5V AAA battery with very minimal load of around 10mA or less. So, the load should work at its best till 0.8V which should be the cutoff voltage of the battery of this kind. Hence its essential to have a performing electronic load at that point. The software could have a feature to show consumed watt hour / ampere hour when battery discharge test is done. It seems, the ADC you have used doesn't have enough throttle for decent performance on CR and CP modes when load voltage changes fast. You need to measure the voltage across the sensing spot of the ADC and then need to calibrate the reading. Otherwise you will have very bad error when jumping from 10V to 20V with a moderate load. YES!!! PCB design doesn't look to be proper for a design with 5 Amp capabilities. Traces are very narrow. You need to fill those narrow traces intended to carry higher currents with solder bumps to have better performance. AND!!! I dont see proper grounding plan for intricate measurements.

Very nice project.Thank you so much. Why not use the current feedback from U7D as the feedback of U7B? So instead of using the precision voltage divider to reduce the control voltage, you can feed the 0-5V from DAC to U7B directly.

What a good (day after) Christmas present! Did you use a microscope to solder that tiny sot23 part?

Really good video. However, can this system (with modifications) be used for much higher voltage values for examble load for tubes. For example 500V 300 mA load.

A good master's job

Thanks for making these detailed videos. I learn a lot from them. one question though, I'm thinking of using the pwm from the arduino through an rc lp filter or alternatively making a resistor ladder (6 or 8bit) connected to one of the ports, do you think that would work as well?

this is really cool! I'm going to build one. Is the PCB pretty much good to go or are you making revisions?

very interesting project

Hello, I'm running through this project but it's more easy for me to use SMD resistors, caps & diodes. I then wonder why you are using polyester box caps and if I could substitute then with regulars SMD caps. Also, I wondered if 2N3904 BJT could not be used instead of the PN2222A as I assumed the amount of current going thought should be fairly low. Thank you so much for your time !