Chapter 2: Bipolar Junction Transistor : Semiconductor Devices & Basic Electronic Systems - F.Y. B.Sc. (Computer Science)

  2.1 Introduction

Q.What is a transistor?

Answer: Transistor is a semiconductor device which regulates the flow of electronic signals.

Q.Draw the PNP and NPN transistor.

Answer: 

1) PNP Transistors:-

2) NPN Transistors:-

Q.Explain the construction of NPN and PNP transistor?

Answer: 

Construction of n-p-n: The n-p-n transistor is formed by sandwiching a thin "p" type semiconductor between two "n" type semiconductors.

Construction of p-n-p: The p-n-p transistor is formed by sandwiching a thin "n" type semiconductor between two "p" type semiconductors.

1) The emitter region is heavily doped.

2) The base region is thin and lightly doped.

3) The collector region area is slightly larger than emitter one's.

Q.Explain the working of NPN transistor.

Answer: Operation of NPN transistor:-

1) It operates in forward active region.

2) Electrons are the majority carriers that move from emitter into base.

3) Some electrons recombine and flow out of the base.

4) Most of the electrons cross the reverse biased collector junction and are collected by supply Vcc.

Q.Explain the working of NPN transistor.

Answer: Operation of NPN transistor:-

1) It operates in forward active region.

2) Electrons are the majority carriers that move from emitter into base.

3) Some electrons recombine and flow out of the base.

4) Most of the electrons cross the reverse biased collector junction and are collected by supply Vcc.