For the emitter follower circuit shown in Fig. 4(b), the signal source is directly coupled to the transistor base. If the dc component of vsig is zero, find the de emitter current. Draw the small signal equivalent circuit and neglecting ro, find Rin, the voltage gain v0/vsig , the current gain, i0/i1 and the output resistance, Rout . Assume, β = 100. Fig. 4( b)
An npn BJT with grounded emitter is operated with VBE = 0.7 V, at which the current is 1 mA. A 10 kΩ resistor connects the collector to a +15 V supply. What is the collector voltage, VC? Now, if a signal is applied to the base raises vbe to 710 mV, find the resulting total collector current, iC and collector voltage, vC. Also calculate the voltage gain, vc/vbe.