I'm trying to make my own rfid reader based on this:
http://www.serasidis.gr/circuits/RFID_reader/125kHz_RFID_reader.htm
But what I want to know is why are two op-amps and a transistor necessary? Couldn't one get away with one op-amp and a higher negative feedback resistor value and still achieve the same gain? or is there something I'm missing?
http://www.serasidis.gr/circuits/RFID_reader/125kHz_RFID_reader.htm
But what I want to know is why are two op-amps and a transistor necessary? Couldn't one get away with one op-amp and a higher negative feedback resistor value and still achieve the same gain? or is there something I'm missing?