Diodes Questions

Diodes are used in electronic devices like television, micro-ovens, refrigerators, computers, mobiles, and storage devices. Diodes have high resistance on one end and low resistance on the other end. An ideal diode is a device with zero resistance in one direction and infinite resistance in the reverse direction.

Semiconductor diodes are the most common type of diodes used. Silicon and germanium are the semiconductor materials used in diode construction. Some of the types of diodes are:

1. Photodiode
2. PN junction diode
3. Light Emitting Diode
4. Zener diode
5. Laser diode
6. Schottky diode
7. Avalanche diode

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A photo-diode can pick out even a small amount of current flow resulting from the light.

The P-N junction diodes are used in the process of rectification. They are also known as rectifier diodes. These diodes are made up of semiconductor material. The P-N junction diodes are of two types: P-type and N-type.

A light-emitting diode, referred to as LED, is a semiconductor device that emits light when electricity flows through it. Electrons recombine with electron holes in the device to release photons. The colour of the light emitted by the diode is found by the energy required for electrons to cross the semiconductor’s bandgap.

A Zener diode is a heavily doped semiconductor device and is designed to function in the reverse direction.

Laser diodes are also known as injection laser diodes. A laser diode is a semiconductor device almost similar to a light-emitting diode (LED). It is a diode that is pumped directly with an electrical current that can create lasing conditions at the diode’s junction. Laser diodes are also known as injection laser diodes. Laser diodes are also known as injection laser diodes.

Schottky diodes have a lower forward voltage than other silicon PN junction diodes. Schottky diodes are highly used in rectifier applications.

Avalanche diodes belong to a reverse bias type and operate using the avalanche effect. Avalanche diodes exhibit high levels of sensitivity and hence are used for photodetection.

Important Diodes Questions with Answers

1. Diodes have _____ terminals

1. 4
2. 3
3. 2
4. 1

Answer: c) 2

Explanation: Diodes are two-terminal devices that conduct electricity in one direction.

2. The positive end of a diode is known as the _____

1. Cathode
2. Anode
3. Ideal end
4. Forward end

Answer: b) Anode

Explanation: The positive end of a diode is known as the anode and the negative end as the cathode.

3. State true or false: Diodes transform AC into DC.

1. TRUE
2. FALSE

Answer: TRUE

Explanation: Diodes transform AC into DC since diodes pass the positive part of the wave and block the negative part of the AC signal, or if diodes are reversed, they pass only the negative part and block the positive part.

4. A reverse-biased diode will act as an _____

1. Closed switch
2. Open switch
3. Both open and closed switch
4. None of the options

Answer: b) open switch

5. Which is the ideal example of the bilateral device

1. Diode
2. Transistor
3. Resistor
4. Silicon controlled rectifier (SCR)

Answer: c) Resistor

Explanation: Among all the options mentioned, the resistor is a bilateral device since it allows current flow in both directions.

6. Red colour light is generated by which of the following diodes

1. Light-emitting diode
2. Avalanche diode
3. Schottky diode
4. Zener diode

Answer: a) Light-emitting diode.

Explanation: Red light is produced by the Light-emitting diode (LED).

7. P-N junction diode allows the current to flow in the ———–

1. Reverse direction
2. Forward direction
3. In both forward and reverse directions
4. None of the options

Answer: b) Forward direction

Explanation: P-N junction diode allows the current to flow forward direction and blocks the current in the reverse direction.

8. When the diode is zero-biased, what would be the voltage potential across the diode?

1. -1
2. 1
3. 0
4. 2

Answer: c) 0

Explanation: The voltage potential across the diode will be zero in a zero-biased diode.

9. What are the types of breakdowns for a Zener Diode?

Types of breakdowns for a Zener Diode are:

• Avalanche Breakdown
• Zener Breakdown

10. In Zener diodes, Avalanche breakdown occurs with Zener voltage (Vz) greater than_____.

1. 0V
2. 2V
3. 4V
4. 6V

Answer: d) 6V

Explanation: In Zener diodes, Avalanche breakdown occurs with Zener voltage (Vz) greater than 6V.

Practice Questions

1. Define a diode.
2. List the types of the diode.
3. What is a laser diode?
4. Explain VI characteristics of PN junction diode.
5. List the applications of the diode.

Watch the video to understand the important questions asked in JEE Mains on the topic of semiconductors and electronic devices.