What is BJT? Explain the naming of transistor terminals. - M R Academic Care

There are two basic transistor types.

i) BJT (Bipolar Junction Transistor)

ii) FET (Field Effect Transistor)

BJT

BJT Stands for Bipolar Junction Transistor. Bi means two and polar refers to polarities, i.e, the term comes from the fact that in a bipolar transistor, there are two types of change carriers (viz, electrons and holes). So BJT is a transistor consists of two pn junctions formed by sandwiching either p-type or n-type semiconductor between a pair of opposite types.

Naming the transistor terminals:

A transistor has three terminals.

i) Emitter

ii) Collector

iii) Base

Emitter

The section on one side that supplies charge carriers (electrons or holes) is called the emitter. The emitter is always forward biased.

Collector

The section on the other side that collects the charges is called the collector. The collector is always reverse biased.

Base

The middle section between the emitter and collector which control charge carriers is called the base. It is very thin as compared to either the emitter on collector