Question

The CE amplifier circuit are preferred over CB amplifier circuit because they have:
(A) low amplification factor
(B) larger amplification factor
(C) high input resistance and low output resistance
(D) none of these

Answer 1

Hint: To understand why CE amplifier circuit is preferred over CB amplifier, we will first see their basic definitions and then try to answer our question. In CE circuits, the base terminal acts as the input, collector terminal acts as the output and emitter is common to both of them. In CB circuit, the emitter terminal acts as the input, collector terminal acts as the output and base is common to both of them.

Complete answer:
There are a number of reasons why we prefer a Common Emitter amplifier circuit over Common Base amplifier circuit. These are listed below:
(a) The first reason is that the resistance offered to the circuit in Common Emitter configuration is much less than resistance offered to the circuit in Common Base configuration.
(b) The power gain in a Common Emitter configuration amplifier circuit is much higher than the power gain in a Common Base configuration amplifier circuit.
(c) Also, in the Common Emitter circuit configuration, the circuit provides a medium input and output impedance levels, as compared to high impedance levels in a Common Base amplifier circuit.
(d) These above stated criterias lead to larger amplification factors in Common Emitter amplifier circuits when compared to amplification factors in Common Base amplifier circuits.
Hence, we can say that the Common Emitter amplifier circuits are preferred over the Common Base amplifier circuit because they have, larger amplification factor.

Hence, option (B) is the correct option.

Note:
The input and output of a Common Emitter configuration are out of phase, that is there is a phase difference of ${180}^0$ between them. Also, due to the larger amplification factor of CE circuits and several other advantages over CB circuits, they are the most abundantly used transistor configuration.