Power Electronics MCQs – Power Electronics Objective Multiple Choice Questions

Power Electronics combines the solid-state electronic components with control and power systems so as to control the electric power systems, drives, and industrial controls. While modern switchyards and substations heavily rely on power electronics, it is crucial to develop a clear image of the entire subject. In this regard, Electrical Engineering XYZ shares power electronics MCQs which are important for electrical jobs, competitive tests, university exams.

The device which performs dc-dc conversion

The device which performs dc-dc conversion:

1. Inverter
2. Rectifier
3. Chopper
4. Switch

Correct answer: 3. Chopper

Explanation: Chopper is an electrical device which converts dc to dc conversion.

• Inverter: An inverter is a power electronics device that converts DC (Direct Current) to AC (Alternating Current). It is commonly used in applications where AC power is required, such as in homes and electrical grids.
• Rectifier: The rectifier is also a power electronic device that performs conversion between AC to DC. It is often used in applications where DC power is needed, such as in electronic devices and power supplies.
• Chopper: A chopper is a device that performs DC-DC conversion. It is used to convert one DC voltage level to another DC voltage level. Choppers use semiconductor switches (typically MOSFETs or IGBTs) to control the flow of current and voltage in order to regulate and modify the DC output. Choppers are commonly used in applications like electric vehicles, renewable energy systems, and adjustable-speed drives.
• Switch: A switch is a generic term used to describe a device or component that can control the flow of electric current. It can be used in various contexts, including both AC and DC circuits. While a switch can be part of a chopper circuit, it does not necessarily refer specifically to a device that performs DC-DC conversion on its own.

Hence 3. Chopper is correct answer.

The DIAC is a

The DIAC is a:

1. One terminal device
2. Two terminal device
3. Three-terminal device
4. Four terminal device

Correct answer: 2. Two terminal device

The TRIAC is

The TRIAC is:

1. An SCR
2. Made up of three DIAC’s
3. Is alike a bi-directional SCR
4. None of these

Correct answer: 3. Is alike a bi-directional SCR

The structure of TRIAC matches two SCR’s which are joined back to back in a parallel fashion. Thus we can relate a TRIAC with a bi-directional SCR.

A thyristor has

A thyristor has:

1. One pn junction
2. Two pn junctions
3. Three pn junctions
4. Four pn junctions

Correct answer: 3. Three pn junctions

Explanation: A thyristor is a semiconductor device commonly used in power control applications. It is a four-layer, three-terminal device that acts as a switch, allowing current to flow in one direction when triggered. The two main types of thyristors are silicon-controlled rectifiers (SCRs) and triacs.

The SCS has

The SCS has:

1. Single gate terminal
2. Two gate terminals
3. Three gate terminals
4. Four gate terminals

Correct answer: 3. Two gate terminals

Forced commutation on SCS can be achieved by

Forced commutation on SCS can be achieved by:

1. Shorting anode and cathode terminals
2. By Applying a negative voltage between anode and cathode
3. Both of these
4. None of these

Correct answer: 3. Both of these

The correct statement about SCR

The correct statement about SCR:

1. SCR is not a rectifier
2. A single SCR can’t be used in full ac control
3. SCR is not used commonly because it is very expensive
4. GTO is a variant of SCR

Correct answer: 3. A single SCR can’t be used in full ac control

PUT stands for

PUT stands for:

1. Programmable Unijunction Transistor
2. Positive Unijunction Transistor
3. Photoconductive Unijunction Transistor
4. Pi Unijunction Transistor

Correct answer: 1. Programmable Unijunction Transistor

A DIAC conducts current in

A DIAC conducts current in:

1. One direction
2. Two directions

Correct answer: 2. Two directions

The LASCR is

The LASCR is:

1. A laser activated SCR
2. A light-activated SCR
3. Lithium anode SCR
4. None of these

Correct answer: 2. A light-activated SCR

Sort the correct statement about DIAC and TRIAC

Sort the correct statement about DIAC and TRIAC:

1. Both are bilateral devices
2. TRIAC is bilateral, but DIAC is unilateral
3. DIAC is bilateral, but TRIAC is unilateral
4. Both are unilateral devices

Correct answer: 1. Both are bilateral devices

Which one the following is not a thyristor

Which one the following is not a thyristor:

1. SCS
2. UJT
3. DIAC
4. TRIAC

Correct answer: 2. UJT

The device which performs dc-ac conversion

The device which performs dc-ac conversion:

1. Inverter
2. Rectifier
3. Chopper
4. Switch

Correct answer: 1. Inverter

The SCS is a _____ terminal thyristor that has _____ gate terminals

The SCS is a _____ terminal thyristor that has _____ gate terminals.

1. Two, two
2. Two, four
3. Four, two
4. Four, one

Correct answer: 3. Four, two

The SCS is turned on by

The SCS is turned on by:

1. Applying a negative pulse on anode gate
2. Applying a positive pulse on anode gate
3. Applying a negative pulse on cathode gate
4. None of these

Correct answer: 1. Applying a negative pulse on anode gate

UJT has ______ pn junction/junctions

UJT has ______ pn junction/junctions:

1. Single
2. Two
3. Three
4. Four

Correct answer: 1. Single

Which one of the following is not a thyristor

Which one of the following is not a thyristor:

1. PUT
2. UJT
3. SCS
4. DIAC

Correct answer: 2. UJT

LASCR is a

LASCR is a:

1. Rectifier
2. Thyristor
3. Both of these
4. None of these

Correct answer: 3. Both of these

The device that has no gate terminal

______ has/have no gate terminal:

1. DIAC
2. TRIAC
3. Both of these
4. None of these

Correct answer: 1. Diac

Explanation: The DIAC has no gate terminal

• Diac: A diac is a two-terminal semiconductor device that is used to trigger and control the conduction of alternating current (AC). It is a bidirectional device, meaning it can conduct current in both directions. The diac does not have a gate terminal. It is typically used in power electronics applications such as triggering triacs and controlling dimmer circuits.
• Triac: A triac is a three-terminal semiconductor device that is also used for controlling AC power. It is similar to a thyristor but can conduct current in both directions. The triac has three terminals: an MT1 (main terminal 1), an MT2 (main terminal 2), and a gate terminal. The gate terminal is used to control the triggering of the device.

The method which can be used to latch Shockley diode

The method which can be used to latch Shockley diode:

1. Exceed the critical rate of voltage rise from anode to cathode
2. Exceed the breakover voltage from anode to cathode
3. Both of these
4. None of these

Correct answer: 3. Both of these

Continue Studying:

1. Power Electronics MCQs Part 1
2. Power Electronics MCQs Part 2
3. Power Electronics MCQs Part 3
4. Power Electronics MCQs Part 4
5. Power Electronics MCQs Part 5
6. Power Electronics MCQs Part 6
7. Power Electronics MCQs Part 7
8. Power Electronics MCQs Part 8
9. Power Electronics MCQs Part 9
10. Power Electronics MCQs Part 10