What is the difference between the operation of n-p-n and p-n-p transistor?

Question

Construction of the both the transistors is simple by the way of doping we do. But the operation is quite confusing.

Comments

+1 good question

Answer 1

BJT - Bipolar Junction Transistors , 

i.e Transistors with a junction of p-type and n-type semiconductors.

These BJ Transistors are used in :

• Switches
• Amplifiers or oscillators

Both PNP & NPN Transistors have same working principle but there are changes in :

• How they are biased
• Polarity of power supply

In simple words , in PNP transistors all voltages and current are reversed as when compared to NPN transistor.

NPN Transistor :

• Current flows from Collector to Emitter
• Electrons are important carriers

Uses:

• Most common use of NPN is switches where it goes ON(Saturation Mode) and OFF(Cut off Mode) in high power devices

PNP Transistor :

• Current flows from Emitter to Collector 
• Hole (positively charged) are important carriers

Uses :
A PNP transistor in a radio boosts the relatively small signal from an antenna

Comments

simple and clear answer. Thank you :)

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its good to hear good comments..thanks