Acg amplifier using an nmos transistor for which gm=4 ma/v has a 5ωk drain resistance rd and a 5kω load resistance rl. the amplifier is driven by a voltage source having a 500ω resistance. what is the input resistance of the amplifier? what is the overall voltage gain av ? by what factor must the bias current id of the mosfet be changed so that rin matches rsig ?