Power Electronics & Industrial Drives
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📘 Comprehensive Syllabus & Examination Guide
Power Electronics & Industrial Drives
Official curriculum roadmap, subject/topic distribution, negative marking rules, pacing guidelines, and solved sample questions.
🎯 Mapped Subjects & Topic Question Distribution
Total Question Pool
100%
35 MCQs
Combined Active Syllabus
Power Electronics & Industrial Drives
35 MCQs
Topic Pool
📊 Question Pool Structure
35 MCQs across fundamental, intermediate, and advanced concept tiers.
⚡ Recommended Pacing
45 to 60 seconds per MCQ. Flag complex problems and preserve 10 minutes for final revision.
⚖️ Scoring & Negative Marking
+1 mark per correct answer. In competitive tests with negative marking, -0.25 applies for incorrect guesses.
💡 Strategic Preparation & Exam Hall Guidelines
To maximize your score on Power Electronics & Industrial Drives, candidates are advised to follow a structured three-pass approach. In the First Pass, solve all direct recall and formula-based questions within 30 seconds each to secure foundational marks. In the Second Pass, tackle multi-step analytical and quantitative reasoning problems. In the Third Pass, review marked questions and verify calculations.
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Showing 10 solved representative questions
📝 Pre-Rendered Solved Sample Questions & Detailed Solutions
Review the solved problems below to understand question phrasing, answer choices, and step-by-step solution logic prior to starting the full interactive practice drill:
Sample Question 1
Power Electronics & Industrial Drives
Medium • Electronics Engineering
An SCR (Silicon Controlled Rectifier) can be brought from the conducting state to the blocking state (turned OFF) by:
A
Applying a negative voltage to the gate
B
Reducing the anode current below the holding current
C
Applying a positive pulse to the cathode
D
Increasing the anode voltage beyond the breakover voltage
✓ Correct Answer: B - Reducing the anode current below the holding current
📖 Step-by-Step Solution & Conceptual Rationale:
Once an SCR is turned ON, the gate loses control. The only way to turn it OFF is by natural or forced commutation, which reduces the anode current below the holding current (Ih).
Sample Question 2
Power Electronics & Industrial Drives
Medium • Electronics Engineering
What is the primary difference between the latching current and the holding current of a thyristor (SCR)?
A
Latching current is associated with turn-off, holding current with turn-on
B
Latching current is associated with turn-on, holding current with turn-off
C
Holding current is always greater than latching current
D
Both currents are identical in magnitude and function
✓ Correct Answer: B - Latching current is associated with turn-on, holding current with turn-off
📖 Step-by-Step Solution & Conceptual Rationale:
Latching current is the minimum anode current required to maintain conduction immediately after gate pulse removal (associated with turn-on). Holding current is the minimum anode current below which the device turns OFF (associated with turn-off). Typically, Ilatching ≈ 2 to 3 × Iholding.
Sample Question 3
Power Electronics & Industrial Drives
Easy • Electronics Engineering
To protect a thyristor against high rates of rise of voltage (dv/dt), which snubber circuit component is connected across it?
A
An inductor in series with a diode
B
A resistor in series with a capacitor connected in parallel with the SCR
C
A fuse in series with the anode
D
A zener diode in series with the gate
✓ Correct Answer: B - A resistor in series with a capacitor connected in parallel with the SCR
📖 Step-by-Step Solution & Conceptual Rationale:
A snubber circuit consisting of a series resistor and capacitor (RC circuit) is connected in parallel with the thyristor to limit dv/dt and suppress transient overvoltages.
Sample Question 4
Power Electronics & Industrial Drives
Easy • Electronics Engineering
To protect a thyristor against high rate of rise of current (di/dt) during turn-on, which component is used?
A
A capacitor in parallel with the SCR
B
A small inductor in series with the anode
C
A metal oxide varistor across the load
D
A fast-recovery diode in antiparallel
✓ Correct Answer: B - A small inductor in series with the anode
📖 Step-by-Step Solution & Conceptual Rationale:
A small inductor connected in series with the thyristor limits di/dt because an inductor opposes instantaneous changes in current, preventing localized hot spots on the silicon die.
Sample Question 5
Power Electronics & Industrial Drives
Easy • Electronics Engineering
A TRIAC is functionally equivalent to which of the following combinations?
A
Two SCRs connected in series
B
Two SCRs connected in inverse-parallel (antiparallel) with a common gate
C
Two diodes connected in antiparallel
D
An SCR and a BJT in Darlington pair
✓ Correct Answer: B - Two SCRs connected in inverse-parallel (antiparallel) with a common gate
📖 Step-by-Step Solution & Conceptual Rationale:
A TRIAC (Triode for Alternating Current) is a bidirectional thyristor equivalent to two SCRs connected in inverse-parallel with gate terminals tied together, allowing conduction in both half-cycles.
Sample Question 6
Power Electronics & Industrial Drives
Medium • Electronics Engineering
A DIAC is commonly used in phase-control circuits to:
A
Rectify AC to DC
B
Trigger a TRIAC symmetrically in both positive and negative half cycles
C
Amplify small audio signals
D
Filter out high-frequency ripple
✓ Correct Answer: B - Trigger a TRIAC symmetrically in both positive and negative half cycles
📖 Step-by-Step Solution & Conceptual Rationale:
A DIAC (Diode for Alternating Current) is a two-terminal bidirectional breakdown diode used to provide sharp, symmetrical triggering pulses to the gate of a TRIAC.
Sample Question 7
Power Electronics & Industrial Drives
Easy • Electronics Engineering
Which power semiconductor device has the characteristics of both a BJT (high current density, low on-state loss) and a MOSFET (high input impedance, voltage-controlled)?
A
GTO (Gate Turn-Off Thyristor)
B
IGBT (Insulated Gate Bipolar Transistor)
C
TRIAC
D
UJT (Unijunction Transistor)
✓ Correct Answer: B - IGBT (Insulated Gate Bipolar Transistor)
📖 Step-by-Step Solution & Conceptual Rationale:
The IGBT combines the insulated gate (voltage-controlled, high input impedance) of a power MOSFET with the bipolar conduction (low saturation voltage drop, high current capability) of a BJT.
Sample Question 8
Power Electronics & Industrial Drives
Easy • Electronics Engineering
What is the output voltage of an ideal Step-Down (Buck) DC-DC converter with input voltage Vin and duty cycle D (0 < D < 1) operating in continuous conduction mode?
A
Vout = Vin / (1 - D)
B
Vout = D × Vin
C
Vout = Vin / D
D
Vout = -D × Vin / (1 - D)
✓ Correct Answer: B - Vout = D × Vin
📖 Step-by-Step Solution & Conceptual Rationale:
In a continuous conduction mode Buck converter, the average output voltage is given by Vout = D × Vin, where D = Ton / T.
Sample Question 9
Power Electronics & Industrial Drives
Easy • Electronics Engineering
In a Step-Up (Boost) DC-DC converter with duty cycle D, the ideal relationship between output voltage Vout and input voltage Vin is:
A
Vout = Vin / (1 - D)
B
Vout = D × Vin
C
Vout = (1 - D) × Vin
D
Vout = D / (1 - D)
✓ Correct Answer: A - Vout = Vin / (1 - D)
📖 Step-by-Step Solution & Conceptual Rationale:
In a Boost converter, Vout = Vin / (1 - D). Since 0 < D < 1, (1 - D) < 1, making Vout always greater than Vin.
Sample Question 10
Power Electronics & Industrial Drives
Medium • Electronics Engineering
A Buck-Boost converter produces an output voltage that is:
A
Always higher than input voltage with same polarity
B
Either higher or lower than input voltage with inverted polarity
C
Always lower than input voltage with inverted polarity
D
Always equal to input voltage regardless of duty cycle
✓ Correct Answer: B - Either higher or lower than input voltage with inverted polarity
📖 Step-by-Step Solution & Conceptual Rationale:
The standard inverting Buck-Boost converter provides Vout = -Vin × (D / (1 - D)). The magnitude can be higher or lower than Vin, and the output polarity is opposite to the input.
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