Hello all, In one of our labs we determined the input impedance of a FET amplifier circuit via a potentiometer. We were told it was due to "maximum power transfer theorem" (something we have not learnt yet). Essentially we attached a potentiometer in series with the input of the circuit and initially had it set to zero. We then adjusted the potentiometer until the initial input voltage was halved. Following, the resistance of the potentiometer was measured, as this resistance was claimed to be equal in magnitude to the input impedance. Is it possible for someone to explain this?