How to Build a Simple DC Electronic Load with Arduino Part 1

[@bernym4047]

I congratulate you on a most excellent video tutorial. No annoying incidental background music. Clear and concise commentary. No irritating introductions and shots of stray cats and kids. Almost perfect video photography. Other you tube makers take note! I am not very experienced or knowledgeable in electronics but followed your explanations very easily. Thank you.

[@technodruid]

You seem intolerable

[@SebastianScholle]

Might be worth noting that the IRF540N doesn't specify a Safe Operating Area under DC conditions in the datasheet. Therefore it is hopeful to state that the part is appropriate for this application. But most mosfets will work anyways, it's just non-ideal unless they are specified for Linear/DC applications.

[@jagjitsinghrehill]

Great timing on this for me. Very relevant. Keep up the awesome work.

[@tommyallehamn]

Very nice to start from the beginning in a very simple way and go on! Hope it will be more complicated circuit in the other parts :) Go ahead 👍

[@luizvision478]

CONGRATULATIONS... I AM SEU FOR PART 2.

[@igorzherebiatev5751]

For what reason do you use an arduino here? if all you need are 5 resistors, 1 potentiometer, and one Zener diode, or tl431

[@ForceTronics]

Good suggestion if you are trying to recreate an eload from the 1980s. But if you want to create a modern eload that supports features such as remote control or dynamic load profiles then a programmable DAC approach might be worth trying

[@claudiu7909]

I would say that the error (or at leas part of it) could be caused by the resistor. The resistor is not exactly 5Ohm. If we assume the ADC is precise enough to give exactly 1 V. And if the current is 0.19399 A (I'l use 0.194A), the value of the resistor in this case would be 1/0.194=5.1546 Ohm If we calculate the error (5.1546-5)/5=0.0309 (aprox 3.1%). If you used a 5% resistor it is very much in realm of possibility for this to be the cause. Of course the resistor is not the only culprit. There are other factors like the precision of the ADC and the measurement precision of the power supply. I would measure the value of the resistor with a multimeter and use that inside the program to calculate the apropriate voltage to use.

[@crocellian2972]

How about using a SPI/I2C DAC? It frees up A0 for use with another serial device (like a heat sink temperature transducer) and you could easily get to the critical 14-16 bit range on the DAC. Maybe you are going there. I should have viewed the series before commenting I guess.

[@ForceTronics]

Adding a higher resolution DAC would definitely improve the design. I would probably want an ADC that matches the DAC resolution for the measurements. I kept this design pretty simple based on what I had at hand. But you make some good suggestions on how to further improve it.

[@T2D.SteveArcs]

OR JUST USE A POT NO NEED FOR ARDUINO

[@avejst]

Thanks for sharing :-)

[@lezbriddon]

A pwm load is a load, but an analog load is the best, shame they need a lot of transistors and heatsinks the size of a house once you get into high amps

[@eishachauhan975]

How can I do the same with Ac current..?

[@ElectronicsForum]

Did you use a gate resistor ? if yes . What was the value ?

[@ForceTronics]

I did not use a gate resistor because MOSFETs draw such little gate current. But if this was a finished commercial design I probably would use a current limiting gate resistor just in case. Probably use 1kohm to 10kohm resistor depending on the MOSFET specs

[@ElectronicsForum]

Thanks for your reply , its working perfectly .

[@dand8282]

i thought no current flows through the gate, so how would a resistor limit anything?

[@av6966]

There must be current flow for anything to work, Voltage without current does nothing. A Mechanic!

[@Mandrag0ras]

@@dand8282 This is exactly what I was taught initially, but when I learned that current does flow and why it does flow, I couldn't understand why we keep perpetuating this misconception. watch?v=8swJ_Bnsgl4

[@rak3shpai]

Thanks for the video. Any reason to use a DAC output? Is that level of precision required? Would a PWM output with a smoothing cap be good enough?

[@ForceTronics]

You are welcome to try it and please share results if it works pretty well. My experience with filtering PWM to make it act like a DAC is you get an output with a lot of low frequency noise. Since MOSFETs are fairly fast devices you will probably see that noise cause the resistance of the MOSFET to jump around and not be stable. Depending on your use model that may not matter.

[@rak3shpai]

That makes sense. Thanks.