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Question
Draw the circuit symbol for NPN and PNP transistors. What is the difference in the Emitter, Base, and Collector regions of a transistor?
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Solution
The circuit symbols of the two types of transistors:
Figure (a)
Figure (b)
The difference in the Emitter (E), the Base (b), and the Collector (C) are as follows:
- Emitter: It is a thick heavily doped layer. This supplies a large number of majority carriers for the current flow through the transistor
- Base: It is the thin, lightly doped central layer.
- Collector: It is a thick and moderately doped layer. Its area is larger than that of the emitter and the base. This layer collects a major portion of the majority of carriers supplied by the emitter. The collector also helps dissipation of any small amount of heat generated.
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