# 7.19 Consider the amplifier circuit of Fig. 7.6 when operated with a supply voltage VCC = +3V. (a) What is the theoretical maximum voltage gain that this amplifier can provide? (b) What value of VCE must this amplifier be biased at to provide a voltage gain of –60 V/V? (c) If the dc collector current IC at the bias point in (b) is to be 0.5 mA, what value of RC should be used? (d) What is the value of VBE required to provide the bias point mentioned above? Assume that the BJT has IS = 10−15 A. (e) If a sine-wave signal vbe having a 5-mV peak amplitude is superimposed on VBE, find the corresponding output voltage signal vce that will be superimposed on V CE assuming linear operation around the bias point. (f) Characterize the signal current ic that will be superimposed on the dc bias current IC. (g) What is the value of the dc base current IB at the bias point? Assume β = 100. Characterize the signal current i b that will be superimposed on the base current I B. (h) Dividing the amplitude of vbe by the amplitude of ib, evaluate the incremental (or small-signal) input resistance of the amplifier. (i) Sketch and clearly label correlated graphs for vBE, vCE, i C, and iB versus time. Note that each graph consists of a dc or average value and a superimposed sine wave. Be careful of the phase relationships of the sine waves.

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