What is transistor? How its work? Where is it used? Part-2

How a transistor is made from N-type and P-type Semi-conductor? 

Two types of transistor can be made from N-type and P-type material. 

• N-P-N Transistor.
• P-N-P Transistor.

N-P-N Transistor and P-N-P Transistor

Fig 3.6.6: P-N-P and N-P-N transistor.(references: google picture)

Characteristics of P-N-P Transistor

• It has two P-type semi-conductor material and one N-type material.
• The current is controlled by base of the transistor.
• The base current is amplified in the collector.
• Emitter emits the holes and holes are collected by the collector.
• Transistor is On when base voltage is low and transistor is off when base voltage is high.

Characteristics of N-P-N Transistor

It has two P-type semi-conductor material and one N-type material.

The majority of charges are carried by electrons.

Without current in the base the N-P-N is normally off

When a small flow of current in the base, the transistor is on state.

The base is controlled the current.

What is depletion Layer? 

 Fig 3.7.7:  Depletion Layer.(References: Electricalworkbook.com)

A P-type material is consists of holes which is a positive charge and a N-type material is consists of free electrons which is negative charge. Holes are attacked with free electron and holes and electrons are combine with each other and form a layer between P and N-type material. Depletion layer is the barrier of flow of electrons. After forming the layer no charge can move from N to P.

The use of Transistor in different Purpose

• Computer, Mobile ,Memory Card use Transistor.
• 5 nm transistor is used in pc.
• Mobile processor use 700-800 cr. transistor.
• It is used in amplifier device.

What will happen if the transistor size is too small?

When the size of a transistor is too small , it is possible to breakdown the depletion layer. If the depletion layer is breakdown ,  transistor will burn because of excessive flow of current.

More information:

https://tb434.blogspot.com/