Question

The corresponding maximum input signal permitted is

(a) 1.64 mV

(b) 1.74 mV

(c) 1.84 mV

(d) 1.94 mV

This question was posed to me in an international level competition.

My question is from BJT in Amplifier Design topic in chapter Bipolar Junction Triodes (BJTs) of Electronic Devices & Circuits

Answer 1

Correct choice is (d) 1.94 mV

Easy explanation: If we assume linear operation right to saturation we can use the gain Av to calculate the maximum input signal. Thus for an output swing ∆ Vo = 0.8 we have

∆ Vi = ∆ Vo / Av = -0.7 / -360 = 1.94 mV.