What does Electronic Devices cover for NEET Physics?

8 lessons: Diode As Rectifier, LED I–V, Logic Gates, Photodiode, Semiconductor Diode I–V, Semiconductors, Solar Cell and Zener Diode.

How often has Electronic Devices come up in NEET past papers?

Our set of verified past papers has 17 questions from this unit, from NEET 2020, 2021, 2022, 2023, 2024, 2025 and 2026. Each is answered against the official NTA key.

Is the Electronic Devices material free?

Yes. All 8 lessons and 64 practice questions are free, with no login needed.

Electronic Devices

8 lessons

Topic index in NCERT order

8 of 8 lessons by the NCERT chapter they teach from, in book order. The page is the first printed page of your NCERT book the lesson cites; PYQs are the past NEET questions on that topic.

Class 12 Physics, Chapter 14

Class 12 Physics (pre-2023 edition), Chapter 14

Zener Diodep. 4852 PYQs
LED I–Vp. 4860 PYQs
Photodiodep. 4860 PYQs
Solar Cellp. 4862 PYQs
Logic Gatesp. 4915 PYQs

Diode As Rectifier

8 MCQs2 PYQs1 revision cardWorked example

Easy Recall (2)Direct Application (3)Calculation (2)Concept Trap (1)

LED I–V

8 MCQsWorked example

Easy Recall (3)Direct Application (3)Concept Trap (1)Calculation (1)

Logic Gates

8 MCQs5 PYQs1 revision cardWorked example

Easy Recall (3)Direct Application (3)Calculation (1)Concept Trap (1)

Photodiode

8 MCQsWorked example

Easy Recall (3)Direct Application (3)Calculation (1)Concept Trap (1)

Semiconductor Diode I–V

8 MCQs4 PYQs2 revision cardsWorked example

Easy Recall (3)Direct Application (3)Concept Trap (1)Calculation (1)

Semiconductors

8 MCQs1 PYQsWorked example

Easy Recall (3)Direct Application (3)Concept Trap (1)Calculation (1)

Solar Cell

8 MCQs2 PYQsWorked example

Easy Recall (3)Direct Application (3)Calculation (1)Concept Trap (1)

Zener Diode

8 MCQs2 PYQsWorked example

Easy Recall (3)Direct Application (3)Concept Trap (1)Calculation (1)

Past-paper questions from this unit

17 questions from NEET 2020, 2021, 2022, 2023, 2024, 2025, 2026. Answers verified against NTA official keys.

By year in our set: 2020 (3) · 2021 (3) · 2022 (3) · 2023 (3) · 2024 (2) · 2025 (1) · 2026 (2)

Lesson: Zener Diode

NEET 2026

An ideal Zener diode with breakdown voltage of −3 V is reverse biased with a negative input voltage Vᵢ = −5 V. The magnitude of voltage difference between points B and A is :

13 V

22 V

31 V

40 V

NTA Answer: Option 2(final)

Report an error · Every fix is public: corrections log

Lesson: Semiconductor Diode I–V

NEET 2026

Three identical p-n junction diodes D₁, D₂ and D₃ are connected across a battery as shown in the figure. If the width of the depletion regions of D₁, D₂ and D₃ are W₁, W₂ and W₃, respectively, then the correct option is :

1W₁ > W₂ > W₃

2W₃ = W₁ > W₂

3W₃ > W₂ > W₁

4W₂ > W₁ = W₃

NTA Answer: Option 3(final)

Report an error · Every fix is public: corrections log

Lesson: Logic Gates

NEET 2025

The output (Y) of the given logic implementation is similar to the output of an/a _____ gate.

1NOR

2AND

3NAND

4OR

NTA Answer: Option 1(final)

Report an error · Every fix is public: corrections log

Lesson: Solar Cell

NEET 2024Revised key

Consider the following statements A and B and identify the correct answer: A. For a solar-cell, the I-V characteristics lies in the IV quadrant of the given graph. B. In a reverse biased pn junction diode, the current measured in (µA), is due to majority charge carriers.

1A is correct but B is incorrect

2A is incorrect but B is correct

3Both A and B are correct

4Both A and B are incorrect

NTA Answer: Option 1(revised_final)

Report an error · Every fix is public: corrections log

Lesson: Logic Gates

NEET 2024Revised key

The output (Y) of the given logic gate is similar to the output of an/a

1NAND gate

2NOR gate

3OR gate

4AND gate

NTA Answer: Option 4(revised_final)

Report an error · Every fix is public: corrections log

Lesson: Diode As Rectifier

NEET 2023

A full wave rectifier circuit consists of two p-n junction diodes, a centre-tapped transformer, capacitor and a load resistance. Which of these components remove the ac ripple from the rectified output?

1p-n junction diodes

2Capacitor

3Load resistance

4A centre-tapped transformer

NTA Answer: Option 2(final)

Report an error · Every fix is public: corrections log

Lesson: Solar Cell

NEET 2023

Given below are two statements: Statement I: Photovoltaic devices can convert optical radiation into electricity. Statement II: Zener diode is designed to operate under reverse bias in breakdown region. In the light of the above statements, choose the most appropriate answer from the options given below.

1Both Statement I and Statement II are incorrect

2Statement I is correct but Statement II is incorrect

3Statement I is incorrect but Statement II is correct

4Both Statement I and Statement II are correct

NTA Answer: Option 4(final)

Report an error · Every fix is public: corrections log

Lesson: Logic Gates

NEET 2023

For the following logic circuit, the truth table is

NTA Answer: Option 1(final)

Report an error · Every fix is public: corrections log

Lesson: Semiconductor Diode I–V

NEET 2022

In the given circuits (a), (b) and (c), the potential drop across the two p-n junctions are equal in

1Both circuits (a) and (c)

2Circuit (a) only

3Circuit (b) only

4Circuit (c) only

NTA Answer: Option 1(final)

Report an error · Every fix is public: corrections log

Lesson: Diode As Rectifier

NEET 2022

In half wave rectification, if the input frequency is 60 Hz, then the output frequency would be

1120 Hz

2Zero

330 Hz

460 Hz

NTA Answer: Option 4(final)

Report an error · Every fix is public: corrections log

Lesson: Logic Gates

NEET 2022

The truth table for the given logic circuit is

NTA Answer: Option 4(final)

Report an error · Every fix is public: corrections log

Lesson: Zener Diode

NEET 2021

Consider the following statements (A) and (B) and identify the correct answer. (A) A zener diode is connected in reverse bias, when used as a voltage regulator. (B) The potential barrier of p-n junction lies between 0.1 V to 0.3 V.

1(A) is incorrect but (B) is correct.

2(A) and (B) both are correct.

3and both are incorrect (A) (B)

4(A) is correct and (B) is incorrect.

NTA Answer: Option 4(final)

Report an error · Every fix is public: corrections log

Lesson: Semiconductors

NEET 2021

The electron concentration in an n-type semiconductor is the same as hole concentration in a p-type semiconductor. An external field (electric) is applied across each of them. Compare the currents in them.

1No current will flow in p-type, current will only flow in n-type

2Current in n-type = current in p-type

3Current in p-type > current in n-type

4Current in n-type > current in p-type.

NTA Answer: Option 4(final)

Report an error · Every fix is public: corrections log

Lesson: Logic Gates

NEET 2021

For the given circuit, the input digital signals are applied at the terminals A, B and C. What would be the output at the terminal y?

NTA Answer: Option 3(final)

Report an error · Every fix is public: corrections log

Lesson: Semiconductor Diode I–V

NEET 2020

For transistor action, which of the following statements is correct ?

1The base region must be very thin and lightly doped.

2Base, emitter and collector regions should have same doping concentrations.

3Base, emitter and collector regions should have same size.

4Both emitter junction as well as the collector junction are forward biased.

NTA Answer: Option 1(final)

Report an error · Every fix is public: corrections log

Lesson: Semiconductor Diode I–V

NEET 2020

The increase in the width of the depletion region in a p-n junction diode is due to :

1increase in forward current

2forward bias only

3reverse bias only

4both forward bias and reverse bias

NTA Answer: Option 3(final)

Report an error · Every fix is public: corrections log

NEET 2020

For the logic circuit shown, the truth table is :

NTA Answer: Option 2(final)

Report an error · Every fix is public: corrections log

Exam traps and common mistakes in this unit

Lesson: Logic Gates

Trap

Logic gate symbol misreading

Category: Similar Terms

Student misreads NAND as AND or NOR as OR. The 'bubble' on the output of NAND/NOR is the negation indicator.

When it triggers

Truth table or logic circuit identification problem.

How to avoid

Check for output bubble. AND with bubble = NAND. OR with bubble = NOR. NAND truth table: outputs 1 EXCEPT when both inputs are 1.

Lesson: Diode As Rectifier

Mistake

Confuses output frequency of half-wave (= input) vs full-wave (= 2× input) rectifier.

Root cause: concept gap

Correction

Half-wave: f_out = f_in (only one half-cycle passes). Full-wave: f_out = 2 f_in (both half-cycles flipped to same polarity).

Lesson: Logic Gates

Mistake

Misreads NAND as AND or NOR as OR by missing the inversion bubble.

Root cause: graph misread

Correction

Output bubble = inversion. AND with bubble = NAND. OR with bubble = NOR. Verify gate symbol carefully before deriving truth table.

Formulas in this unit

Lesson: Diode As Rectifier

Rectifier output frequency

f_{out} = 2 f_{in} (full)

Output ripple frequency relative to input AC frequency.

Symbol	Quantity	SI Unit
f_in	input AC frequency	Hz
f_out	output ripple	Hz

Valid when

Single-phase AC input
No filter (raw rectified output)

Lesson: Logic Gates

Common logic gate truth tables

AND, OR, NOT, NAND, NOR, XOR

Boolean operations on binary inputs. NAND and NOR are universal gates.

Symbol	Quantity	SI Unit
A, B	binary inputs (0 or 1)	-
Y	binary output (0 or 1)	-

Valid when

Binary digital logic
Ideal gates (no propagation delay considered)

Lesson: Semiconductor Diode I–V

p-n diode bias regimes

Forward: V_{F} > 0; Reverse: V_{R} < 0

Conceptual: p-n junction conducts in forward bias, blocks in reverse (until breakdown).

Symbol	Quantity	SI Unit
V_F	forward voltage	V
V_R	reverse voltage	V

Valid when

Single p-n junction
DC operation

NEET question patterns in this unit

Lesson: Diode As Rectifier

Determine bias direction or rectified output. Half vs full wave rectifier output frequency.

InterpretationEasy

Common distractors

swaps half full wave

Confuses rectifier types

Lesson: Logic Gates

Given logic circuit, derive Y from inputs A, B. Truth table identification or Boolean simplification.

InterpretationMedium

Common distractors

misreads gate symbol

Confuses NAND with AND or NOR with OR

Lesson: Zener Diode

Zener diode in reverse breakdown stabilises voltage. Identify operating point.

InterpretationEasy

Common distractors

uses forward bias

Treats Zener like ordinary forward-biased diode

Questions about this unit

What does Electronic Devices cover for NEET Physics?: 8 lessons: Diode As Rectifier, LED I–V, Logic Gates, Photodiode, Semiconductor Diode I–V, Semiconductors, Solar Cell and Zener Diode.
How often has Electronic Devices come up in NEET past papers?: Our set of verified past papers has 17 questions from this unit, from NEET 2020, 2021, 2022, 2023, 2024, 2025 and 2026. Each is answered against the official NTA key.
Is the Electronic Devices material free?: Yes. All 8 lessons and 64 practice questions are free, with no login needed.