STUDY MATERIAL · GATE EC
GATE Electronic Devices previous year questions and notes
Every Electronic Devices question from 7 GATE papers (2018–2026), solved step by step and checked against the organising institute’s official answer key — with notes for each topic, a formula sheet and practice questions.
- previous-year questions
- 39previous-year questions
- worked solutions, checked against the key
- 37worked solutions, checked against the key
- GATE papers, 2018–2026
- 7GATE papers, 2018–2026
- topics with notes
- 6topics with notes
TOPICS
Six topics, in the order they are taught
Cut from the official GATE 2027 syllabus. Each topic has notes, the formulas you need, every previous-year question on it with a checked solution, and practice questions.
- TOPIC 01
Energy bands and carrier concentration
Energy bands and carrier concentration covers how the discrete levels of isolated atoms broaden into a valence band and a conduction band separated by a forbidden gap $E_g$, and how temperature and doping set the equilibrium electron and hole concentrations.
9 previous-year questions · 12 marks · 6 practice
- TOPIC 02
Carrier transport: drift, diffusion, generation and recombination
Current in a semiconductor is the sum of drift (carriers pushed by an electric field) and diffusion (carriers spreading down a concentration gradient).
9 previous-year questions · 15 marks · 6 practice
- TOPIC 03
P-N junctions and Zener diodes
How a junction between p-type and n-type silicon builds a built-in potential and a depletion region, and how the depletion width, peak field and depletion capacitance depend on doping and bias.
6 previous-year questions · 8 marks · 4 practice
- TOPIC 04
The bipolar junction transistor as a device
A bipolar junction transistor (BJT) has three terminals: emitter, base and collector.
3 previous-year questions · 5 marks · 6 practice
- TOPIC 05
MOS capacitor, MOSFET and scaling
Study notes for the GATE Electronic Devices topic 'MOS capacitor, MOSFET and scaling' (EC syllabus): conventions, oxide capacitance, work-function difference and flat-band voltage; accumulation, depletion, weak and strong inversion; threshold voltage for NMOS and PMOS with body effect and threshold-adjust implant; low- and high-frequency C-V and C_min; the square-law I-V model with channel-length modulation; transconductance, body transconductance and f_T; subthreshold conduction and swing; constant-field vs constant-voltage scaling and short-channel effects.
7 previous-year questions · 11 marks · 5 practice
- TOPIC 06
LEDs, photodiodes and solar cells
This topic covers how a p-n junction converts between light and electrical energy.
5 previous-year questions · 10 marks · 6 practice
WHERE THE QUESTIONS FALL
39 questions, by topic and year
Counts across the EC papers of each year. A count of what was asked, not a forecast of what will be. The topic tags are IAE’s reading of each question, and every question links back to its paper.
| Topic | 2018 | 2020 | 2022 | 2023 | 2024 | 2025 | 2026 | Total |
|---|---|---|---|---|---|---|---|---|
| Semiconductors | 1 | 1 | 1 | 3 | 2 | 1 | · | 9 |
| Carrier transport | · | 1 | 3 | 1 | 1 | 2 | 1 | 9 |
| P-N junction | 2 | 1 | · | · | · | 1 | 2 | 6 |
| BJT | · | 1 | · | · | 1 | · | 1 | 3 |
| MOS devices | · | 1 | 3 | 1 | 2 | · | · | 7 |
| Optoelectronics | 2 | 1 | · | · | 1 | · | 1 | 5 |
The 2019 and 2021 papers are not yet included: the copies we host are image scans that do not carry the official key, so no solution to them could be checked.
How we check solutions: editorial standards.
Electronic Devices formulas by topic
Preparing in Kolkata? See IAE Academy’s GATE EC coaching.
THE OFFICIAL SYLLABUS
What each paper lists under Electronic Devices
Verbatim from the GATE 2027 syllabus PDF: EC Section 3, “Electronic Devices”. Only EC gives devices a section: IN names types of diode and BJT and MOSFET circuits under Analog Electronics, and EE names the thyristor, MOSFET and IGBT only as power switches, under Power Electronics.
GATE EC
Formation of energy bands in solids, energy bands in intrinsic and extrinsic semiconductors, equilibrium carrier concentration, direct and indirect band-gap semiconductors. Carrier Transport: Diffusion current, drift current, mobility and resistivity, generation and recombination of carriers, Poisson and continuity equations. P-N junction, Zener diode, BJT, MOS capacitor, MOSFET, scaling in MOSFETs, LED, photo diode and solar cell.
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