1. consider the following equivalent circuit model of a bipolar transistor at a certain bias point (vbe, vbc) in the forward-active regime. a) calculate ic at which the device is biased. b) calculate the current gain, βf, of the transistor. c) calculate the short-circuit current-gain cut-off frequency, ft, of this device at this bias point. d) calculate the early voltage, va, of the transistor. e) derive values for all small-signal elements of the equivalent circuit model of another transistor fabricated side-by-side to the one above but with an emitter stripe length that is twice as long. the device is biased at the same voltages (vbe, vbc) as the above device