my big problem is i can't understand the operation of the differential amplifier on the figure1, but i have my thoughts on my mind as i've analyzed the circuit given by m friend(forumite)
so just for clarification, the diff.amplifiers tends to compare the voltages before and after the sense resistor? actually the circuit i've attached is not finished, because we don't know where to attached the output of the differential amplifier...
yes, fe told me to use any gen.purpose operational amplifiers for the diff.amplifier.. he didn't told me about the capacitors on the diff.amplifier, but i think those will serve as filters for unnecessary AC signals.