NPN Transistor Questions

A bipolar junction transistor is a three-terminal semiconductor device that features two p-n junctions that amplify the signal.

Two types of BJT transistors are:

• PNP bipolar junction transistor
• NPN bipolar junction transistor

NPN is a type of bipolar junction transistor where a p-type semiconductor is placed in between two n-type semiconductors. The one n-type semiconductor functions as a collector and an emitter, while the p-type semiconductor acts as a base.

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Important NPN Transistor Questions with Answers

1. What are the various parts of the transistor?

Base, collector and emitter are the various parts of the transistor.

2. Who invented the transistor?

In 1947, W. Shockley, W. Brattain, and J. Barden invented the transistor.

3. The diode between collector and base terminal is known as _______

1. Emitter-base diodes
2. Collector-base diodes
3. Collector-base diodes
4. Base-base diodes

Answer: b) Collector-base diodes

Explanation: Collector-base diodes are formed between the collector and base terminal.

4. Choose the right answer: What are the majority charge carriers in NPN transistors?

1. Holes
2. Electrons

Answer: b) Electrons

Explanation: Electrons are the majority charge carriers in NPN transistors.

5. Which region in BJT transistors works as an amplifier?

1. Cut-off region
2. Saturation region
3. Active region
4. None of the options

Answer: c) Active region

Explanation: In the active region, transistors operate as an amplifier.

6. Name five other types of transistors.

MOSFET, inverted-T field-effect transistor, JFET, insulated-gate bipolar transistor, and diffusion transistor.

7. State true or false: Transistor offers fast switching.

1. TRUE
2. FALSE

Answer: a) TRUE

Explanation: The transistor acts as a switch and is an ideal device for switching operation.

8. How is electricity formed in the NPN transistor?

The electrons move from the emitter to the collector resulting in the formation of current in the NPN transistor.

9. Lightly doped region of the transistor is ______

1. Emitter
2. Collector
3. Base
4. None of the options

Answer: c) Base

Explanation: The Base is the lightly doped region of the transistor.

10. What are the operative modes of a transistor?

Operative modes of the transistor are:

• Cut-off mode
• Saturation mode
• Active mode

Practice Questions

1. What is a transistor?
2. What are the types of transistors?
3. What is a Field Effect Transistor (FET)?
4. What is an NPN transistor?
5. What is a PNP transistor?