this is a precise load to be controlled by a microcontroller.
I had some noise trouble using ACS714 , the “0” level (digitized by an 16 bit ADC) is changing, and there is always a 10-20 step noise in the PWM readout.
So I decided to go with a resistor.
the ADC is using vrev 4.096 , so it’s measuring between GND and the otehr side of the 1ohm resistor.
ADC is now calibrated, and works fine.
Load is controlled by a DAC with range 0…5V
Lestmost transistor (PNP) is a MJ11015 (hFE=1000 darligton) , the NPN is there only to invert the 0…5v signal and is a BD139
in simulation it works, but there’s unexpected high current on the NPN - anyway - can YOU suggest a better way to drive the PNP’s basis ? (keeping in mind the 11.9 volt supply can be 3…30v) - and the drive-voltage can only be 0…5v ?