Question

An n-p-n transistor circuit is arranged as shown in the figure. It is common:
A. Base amplifier circuit
B. Emitter amplifier circuit
C. Collector amplifier circuit
D. None of these

Answer 1

Hint: A junction transistor is formed by sandwiching a thin layer of a p-type semiconductor between two layers of n-type semiconductor or by sandwiching a thin layer of an n-type semiconductor between two layers of p-type semiconductor. N-P-N transistor has three terminal-emitter, collector, and base. In the N-P-N circuit, the emitter is always forward biased while the base and collector are reversed biased.

Complete step-by-step solution
We know that the transistor in which two N-type semiconductor materials are separated by a thin layer of P-type semiconductors they are called an N-P-N transistor, As the N-P-N transistor, has three terminal- emitter-collector and base in this type of transistor the majority carriers are the electrons.
Now, in N-P-N transistor circuits the direction of movement of electrons is from the emitter to the collector region which forms the current flow in the transistor because we know that the movement of electrons generates the current in the circuit.

As shown in the diagram which is given in the question, the N-P-N transistor circuit is arranged in the figure. It is a common emitter amplifier circuit because emitter (N) is common to both the base (P) and collector (N) therefore; it is a common emitter amplifier circuit because the emitter is common in a given circuit. So the correct option is (B).

Note: The middle section of the N-P-N circuit is lightly doped, that is the base while the emitter is moderately doped and the collector is heavily doped. These N-P-N transistors are mostly used in circuits for amplifying and switching signals. Because their majority charge carriers are electrons.