Question

If the emitter bypass capacitor is open , the ac output voltage will ____________

(a) decrease

(b) increase

(c) remains the same

(d) equals zero

This question was addressed to me by my school teacher while I was bunking the class.

This key question is from Voltage Amplifiers topic in chapter Differential and Multistage Amplifiers of Electronic Devices & Circuits

Answer 1

Right choice is (a) decrease

For explanation: The emitter bypass capacitor is connected in parallel to the emitter resistance. The use of this connection is to provide an ac ground at the emitter terminal of the transistor. This has the effect of increasing the circuit voltage gain.

The bypass capacitor is normally a high-value component that provides little reactance at the lowest circuit operating frequency. Therefore, in the absence of this bypass capacitor, the circuit voltage gain will reduce.