Free Power Electronics MCQs with Answers
253 Power Electronics MCQs from Electrical Engineering, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
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- A. A D.C source
- B. an A.C source
- C. any source
- D. all of the above
Explanation: Electroplating requires a unidirectional current so that metal ions move consistently toward the object being plated.
Correct answer: A D.C source- A. Silicon diodes
- B. Mercury arc rectifier
- C. Motor generator set
- D. Any of the above
Explanation: Silicon diodes and mercury-arc rectifiers convert AC to DC directly, while a motor-generator set performs the conversion…
Correct answer: Any of the above- A. of 10%
- B. of 15%
- C. of 25%
- D. within 1%
Explanation: Well-designed commercial power supplies are intended to maintain their output close to the rated value, commonly with regulation within…
Correct answer: within 1%- A. Voltage
- B. Current
- C. Voltage as well as current
- D. None of the above
Explanation: An SCR is normally turned on by applying a gate current pulse while it is forward biased.
Correct answer: Current- A. Is inexpensive
- B. Is mechanically strong
- C. Has small leakage current
- D. Is tetravalent
Explanation: Silicon is preferred for SCRs because its reverse leakage current is much smaller than that of germanium, improving blocking performance.
Correct answer: Has small leakage current- A. Equal to
- B. Less than
- C. Greater than
- D. None of the above
Explanation: The supply is normally kept below the SCR's breakover voltage so it does not turn on unintentionally.
Correct answer: Less than- A. Breakover voltage
- B. Appropriate anode current
- C. Appropriate gate current
- D. None of the above
Explanation: An SCR is normally triggered by applying an appropriate positive gate current with respect to the cathode.
Correct answer: Appropriate gate current- A. A rectifier and resistance
- B. A rectifier and transistor
- C. A rectifier and capacitor
- D. None of the above
Explanation: An SCR combines the one-way current control of a rectifier with the switching and control action associated with a transistor.
Correct answer: A rectifier and transistor- A. Reducing anode voltage to zero
- B. Reducing gate voltage to zero
- C. Reverse biasing the gate
- D. None of the above
Explanation: Reducing the anode voltage to zero removes forward bias and turns the SCR off.
Correct answer: Reducing anode voltage to zero- A. Cathode
- B. Anode
- C. Anode supply
- D. Gate
Explanation: The gate is the control terminal of an SCR and receives the triggering pulse.
Correct answer: Gate- A. At zero potential
- B. Negative
- C. Positive
- D. None of the above
Explanation: For forward operation, the anode must be positive with respect to the cathode, establishing forward bias across the SCR.
Correct answer: Positive- A. Unidirectional
- B. Bidirectional
- C. Mechanical
- D. None of the above
Explanation: An SCR permits controlled current flow mainly in one direction, from anode to cathode, so it behaves as a unidirectional switch.
Correct answer: Unidirectional- A. Positive
- B. Negative
- C. At zero potential
- D. None of the above
Explanation: To trigger a conventional SCR, the gate is made positive with respect to the cathode by applying gate current.
Correct answer: Positive- A. Triac
- B. Diac
- C. Unijunction transistor
- D. Thyristor
Explanation: SCR stands for silicon-controlled rectifier and is a member of the thyristor family.
Correct answer: Thyristor- A. Triode
- B. Pentode
- C. Gas-filled triode
- D. Tetrode
Explanation: An SCR is the solid-state counterpart of a gas-filled triode, commonly called a thyratron.
Correct answer: Gas-filled triode- A. Cathode, anode, gate
- B. Anode, cathode, grid
- C. Anode, cathode, drain
- D. None of the above
Explanation: An SCR is a three-terminal thyristor with anode and cathode for the main current path, plus a gate for triggering.
Correct answer: Cathode, anode, gate- A. Germanium
- B. Silicon
- C. Carbon
- D. None of the above
Explanation: SCRs are fabricated from silicon because it withstands high blocking voltage, temperature, and power levels.
Correct answer: Silicon- A. Two
- B. Three
- C. Four
- D. None of the above
Explanation: An SCR has four alternate semiconductor layers: P-N-P-N. These layers form the three internal pn junctions of the device.
Correct answer: Four- A. Two
- B. Three
- C. Four
- D. None of the above
Explanation: The four-layer P-N-P-N structure contains three interfaces between adjacent layers, so an SCR has three pn junctions.
Correct answer: Three- A. Anode current is reduced to zero
- B. Gate voltage is reduced to zero
- C. Gate is reverse biased
- D. None of the above
Explanation: An SCR turns off when its anode current falls below the holding current, which is commonly approximated as reducing the current to zero.
Correct answer: Anode current is reduced to zeroPower Electronics MCQs: common questions
Are these Power Electronics MCQs free?
Yes. All Power Electronics MCQs from Electrical Engineering are free on TestUstad, with unlimited attempts and no account needed. Nothing on this page is a sample or a trial.
How many Power Electronics MCQs are on this page?
There are 253 Power Electronics MCQs in the Electrical Engineering bank, shown 20 to a page with the correct answer and an explanation on each.
Does every Power Electronics MCQ have an explanation?
Yes. Each Power Electronics question shows the correct option and a written explanation of why it is correct, so a wrong answer teaches you something rather than just being marked wrong.
Can I take a timed Power Electronics test?
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