DC Electronic Load

when testing of dc power supply, DC-DC convertor, Linear regulators, and battery we need some kind of instrument which sink constant current from source.

we can use constant value resistor but in case of battery we need to change resistor with voltage droop so it become complicate

hear i use IRF250 power MOSFET for power sink device. while MOSFET sink power is convert into heat so for cooling MOSFET i use old processer's heat sink and also added 100k 2w resistor across Gate and source terminal

hear i connect one source to drain and source and other source between gate and source by increasing gate terminal voltage other power supply sink current hear MOSFET is work as electronic resistor

for control current we need to measure current reading for measuring current i use Shunt resistor method

hear i take 0.1 ohm 10w resistor and by calculation we get max current from resistor is 10A and max voltage is 1V which is very low for operation

i deside to make circuit to give 1v for 1a and for that i desigh this differintial opamp circuit with gain of 100 and for that i take 1k and 100k rsistor

after gating current signal from differential OPAMP i give that signal to comparator and compare that with potentiometer , if differential OPAMP's out put is lase than pot then comparator OPAMP give high out put else it give low output. hear i make circuit for 5A max so i give 5v to potentiometer

by making circuit on breadboard and test it i make circuit on pcb board i also added power panel to monitor voltage and current

i make this enclosure from electrical box