Question

Which of the following configuration is used for impedance matching?

(a) Common base configuration

(b) Common emitter configuration

(c) Common collector configuration

(d) All configurations are equally suited

I have been asked this question by my school principal while I was bunking the class.

Enquiry is from Operating Point of Transistor topic in chapter Transistor Biasing and Low Frequencies of Analog Circuits

Answer 1

Right option is (c) Common collector configuration

The best explanation: Common base configuration is used as input stage of multistage amplifier since it has low input resistance and high output resistance. Since voltage gain is high, common emitter configuration is used for audio signal amplification. Common collector is used for impedance matching since the voltage gain is unity.