Introduction to transistors

Transistor- 

A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power.It consists of semiconductor material usually with atleast 3 pins for connection to an external circuit.It can act as  either an insulator or a conductor by the means of small signal voltage. 

A transistor can be used for switching(digital electronics) or amplification(analog electronics).

Bipolar transistor consists of three layers, these are constructed by two pn junctions connected back-to-back such that they share a common P or N terminal.

These are of two types :- NPN AND PNP.

• Configurations for bipolar transistors-

1. Common emitter - both current and voltage gain.

2. Common base - has only voltage gain.

3. Common collector - has only current gain.