Hello again, fellows.
After carefully reading and trying to make sense of all you wrote, I found a circuit online that has lots of similarities to what I want and I tested it. First I simulated it on Multisim 14 (schematics and numbers below) then I breadboarded it with 100% success.
As it is on the breadboard right now, it is already good enough for most of what I want, but I want more. This is the list of features that I'll implement on my electronic load:
- up to 4A using SSS7N60A
- LM35 (in TO-92) attached to the FET to monitor its temperature
- old CPU heatsink + fan, with speed controlled by the Arduino
- 1Mbit EEPROM memory to save data points: elapsed time, load (A), voltage, temperature
- interval at which data points are saved and if they are saved is user-defined
- relay to turn load on/off
- a few LEDs (what is a tech device without LEDs)? How do you guys feel about blue LEDs @ 20mA ?
- ability to pulse the load (at 968 Hz, user-defined duty cycle)
- 3 operation modes: constant current, constant voltage, constant power
- fuse (4A)
- Nokia 5110 display to show everything
- output of data through the USB/Serial connection (can be turned on/off)
- ability to import the EEPROM data to the computer through the USB/serial
I might create a topic to post progress on the build and to post the Arduino sketch and schematics (it's the least I can do to return the huge help).
Again, thank you very much for your valuable help.