Power Electronics: notes and questions
Notes for each topic, a formula sheet, practice questions and 42 past GATE questions from 7 papers (2018–2026), 41 of them solved step by step.
- previous-year questions
- 42previous-year questions
- solved step by step
- 41solved step by step
- GATE papers, 2018–2026
- 7GATE papers, 2018–2026
- topics with notes
- 5topics with notes
Foundation
Learn the subject one topic at a time. Each topic has notes, the key formulas and practice questions.
Topic notes and formulas
Notes on every topic, with the key formulas and practice.
- GATE EE only
Power semiconductor switches and their gating
This topic covers the static V-I characteristics of the thyristor (SCR), power MOSFET and IGBT, with the power diode, TRIAC and GTO for comparison, and how each device is switched on and off by its gate.
6 practice questions
DC-DC converters: buck, boost and buck-boost
DC-DC converters change a DC voltage level by switching an inductor and a capacitor, and the buck, boost and buck-boost circuits are the three basic ones.
5 practice questions
Uncontrolled and controlled rectifiers, AC-DC converters
How diodes and thyristors turn AC into DC: average and rms output, ripple, the effect of the firing angle, source inductance and overlap, inversion, thyristor commutation, and the converters built from them (dual converters, AC voltage controllers, PWM voltage source converters and DC drives).
7 practice questions
- GATE EE only
Line-current harmonics, power factor and distortion factor
A diode or thyristor rectifier draws a non-sinusoidal line current, so the supply sees harmonics, and reactive power when the converter is phase-controlled, even when the load current is pure DC.
6 practice questions
Inverters and pulse width modulation
An inverter turns a dc supply into an ac output of chosen magnitude and frequency, and pulse width modulation (PWM) shapes that output.
7 practice questions
Power Electronics formulas by topic
GATE
Past GATE questions on Power Electronics by topic and year, the full papers, practice and the GATE syllabus.
42 questions, by topic and year
How many questions each topic had in the EE papers of each year. This shows what was asked, not what will be asked. We placed each question under a topic ourselves; the exam paper does not label topics.
| Topic | 2018 | 2020 | 2022 | 2023 | 2024 | 2025 | 2026 | Total |
|---|---|---|---|---|---|---|---|---|
| Switches | 1 | 1 | 1 | 2 | 2 | · | 2 | 9 |
| DC-DC converters | 2 | 1 | 1 | 1 | 1 | 2 | 1 | 9 |
| Rectifiers | 2 | 2 | 1 | 1 | 2 | 2 | 2 | 12 |
| Harmonics & PF | 1 | 1 | 2 | · | 1 | 1 | · | 6 |
| Inverters & PWM | · | 1 | 2 | · | 1 | 1 | 1 | 6 |
31 practice questions
The GATE syllabus for Power Electronics, paper by paper
Verbatim from the GATE 2027 syllabus PDFs: EE Section 10, “Power Electronics”, and the machines part of IN Section 3, which lists buck and boost converters, rectifiers, single-phase inverters, rotor position, speed and current sensing, and PWM control. EC's syllabus has no power electronics: its “converters” are code converters and data converters.
Show the GATE EE wordingHide the GATE EE wording
Static V-I characteristics and firing/gating circuits for Thyristor, MOSFET, IGBT; DC to DC conversion: Buck, Boost and Buck-Boost Converters; Single and three-phase configuration of uncontrolled rectifiers; Voltage and Current commutated Thyristor based converters; Bidirectional ac to dc voltage source converters; Magnitude and Phase of line current harmonics for uncontrolled and thyristor based converters; Power factor and Distortion Factor of AC to DC converters; Single-phase and three-phase voltage and current source inverters, sinusoidal pulse width modulation.
Show the GATE IN wordingHide the GATE IN wording
buck and boost converters, rectifiers, single phase inverters; rotor position and speed sensing, current sensing, pulse width modulation (PWM) control.
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