For the circuit below, determine a) the impedance (1/y11) parameter at the emitter terminal b) the voltage gain from the voltage source taking into account all the components in the circuit. c) calculate the change in base emitter voltage if the collector current increases 2 times and then 10 times. Assume ro >> (rpi + rb) and ro>> rc

ro Rs vi E Vo gm v1 Vs V? rpi. HE Rc + rb B