Class 12 Physics, Chapter 14 Semiconductors Class 12 Physics, Chapter 14 Semiconductor | Page 10

A transistor is an arrangement obtained by growing a thin layer of one type of semiconductor between two thick layers of other similar type semiconductor .
Types of Transistors
The left side semiconductor is called emitter , the right side semiconductor is called collector and the thin middle layer is called base .
� Emitter is highly doped and base is feebly doped .
� A transistor can be utilized as an amplifier and oscillator but not a rectifier
� Maximum amplification is obtained in common-emitter configuration .
Transistor as an Amplifier
An amplifier is a device which is used for increasing the amplitude of variation of alternating voltage 01 ′ current or power .
The amplifier thus produces an enlarged version of the input signal .
The general concept of amplification is represented in figure . There are two input terminals for the signal to be amplified and two output terminals for connecting the load ; and ’ a means of supplying power to the amplifier .
1 . In Common Base Amplifier ,