TRANSISTOR

TRANSISTOR:

  The term transistor made up of two different word ‘tran’ and ‘sistor’, where ‘tran’ means transfer and ‘siistor’ means resistor. Thus transistor is an electronic material which is used to transfer of resistor. And it was invented in late 1947.

TYPES:

  There are two mean type of resistor,

          a.       BJT transistor (Bipolar Junction Transistor)

          b.      FET transistor (Field Effect Transistor)

From where this two are subdivided into two separate types

For BJT transistor it is divided into (1) npn transistor (2) pnp transistor.

For FET transistor it subdivided into (1) MOSFET transistor (2) JFET transistor.

But here we going to see about BJT transistor npn and pnp transistor

CONSTRUCTION:

BJT Transistor

transistor diagram

  BJT transistor is mainly consist of three terminals ( Base, Collector, Emitter)

  Ø  Its consist of two pn junction layer (1) Base-emitter junction (2) Collector base junction

  Ø  The base junction is highly doped highly doped mean region have high amount of electrons.

  Ø  Collector is moderately doped.

  Ø  Emitter is heavily doped

  Ø  The base region area is thin

  Ø  The collector region area is wider

     Ø  The emitter region area is greater than base region but less than collector region. 

npn transistor