STUDY MATERIAL · GATE EC
GATE Electronic Devices: questions and notes
Electronic Devices questions from 7 GATE papers (2018–2026) with the official answers, 37 of 39 solved step by step, plus notes for each topic, a formula sheet and practice questions.
- previous-year questions
- 39previous-year questions
- solved step by step
- 37solved step by step
- GATE papers, 2018–2026
- 7GATE papers, 2018–2026
- topics with notes
- 6topics with notes
TOPICS
Six topics, in the order they are taught
Taken from the official GATE 2027 syllabus. Each topic has notes, the formulas you need, its previous-year questions with the official answers, most of them solved step by step, and practice questions.
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 questions
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 questions
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 questions
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 questions
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 questions
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 questions
QUESTIONS BY TOPIC AND YEAR
39 questions, by topic and year
How many questions each topic had in the EC 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. 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 included yet: the copies we host are image scans without the official key.
Electronic Devices formulas by topic
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THE OFFICIAL SYLLABUS
What each paper lists under Electronic Devices
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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