Are these Power Electronics handwritten notes free?

Yes. Fill in the short form on this page and the PDF downloads right away. There is no fee for the notes.

Are these official university notes?

No. These are original Uncodemy revision notes for Power Electronics. They are not issued or approved by AKTU or any other university, and they are not past papers.

Which syllabus do they follow?

They follow the common B.Tech syllabus for Power Electronics used by most Indian universities, including AKTU and colleges on the AICTE model curriculum. Unit order and depth differ, so match the notes with your own university syllabus.

Are waveforms included?

Yes. The rectifier, chopper and inverter units include output waveforms, because most exam answers in this subject need them.

Do the notes cover IGBT and MOSFET?

Yes. The first unit compares power diodes, SCR, GTO, power MOSFET and IGBT and says where each is used.

Power Electronics Handwritten Notes PDF

Key takeaways

Seven units, from power devices to applications.
SCR characteristics, latching and holding current, commutation and snubbers are explained.
Single-phase and three-phase full converter outputs are solved with numbers.
Buck and boost converters with inductor ripple, inverters, sinusoidal PWM and AC controllers are covered.
Original Uncodemy revision notes, not official university notes. Check your own syllabus.

About these handwritten notes

These Power Electronics notes are original Uncodemy revision notes, written in a clean handwritten style so they are quick to read before an exam. They follow the common B.Tech syllabus for Power Electronics (B.Tech EE, EEE and ECE, and GATE EE basics). They are not official university notes and not copied from any textbook or past paper.

Topic order, unit numbers and depth vary between universities, so first place each unit below against your own university syllabus. If your syllabus has a topic that is missing here, add it in the margin from your class notes or textbook. Use these notes for revision after you have studied the topic once in class, not as your only study material. They are short on purpose: the aim is to help you recall the main ideas, formulas and diagrams quickly, so that your exam time goes into writing good answers.

What's inside the Power Electronics notes

Each unit pairs a circuit with its output waveform and the main formula. Waveforms are drawn because most marks in this subject come from correct waveform sketches.

Unit 1: Introduction and Power Devices. Types of converters and a comparison of power diodes, SCR, GTO, power MOSFET and IGBT.
Unit 2: Thyristor (SCR). V-I characteristics, latching and holding current, turn-on methods, commutation, protection and series and parallel operation.
Unit 3: Phase-Controlled Rectifiers. Single-phase and three-phase half, semi and full converters, inverter mode and dual converters.
Unit 4: DC-DC Converters (Choppers). Step-down (buck) and step-up (boost) converters, duty cycle, inductor ripple and chopper classes.
Unit 5: Inverters. Single-phase and three-phase voltage source inverters, 180° and 120° modes, and PWM methods.
Unit 6: AC Voltage Controllers and Cycloconverters. Phase control, integral cycle control and cycloconverter basics.
Unit 7: Applications. Uses in drives, UPS, SMPS, HVDC and renewable energy systems.

The last page of the PDF lists the most asked practice questions for the whole subject, so you can test yourself after finishing all the units.

Formulas and solved examples in the PDF

Formula boxes cover rectifier average voltage for single-phase and three-phase converters, buck output Vo = DVs, boost output Vo = Vs/(1 - D), inductor ripple and modulation index. Solved examples include a single-phase full converter at 230 V and α = 30°, a three-phase full converter at 415 V and α = 60°, a 48 V buck converter with ripple, and a 12 V boost converter at D = 0.6.

How to revise Power Electronics with handwritten notes

Handwritten-style notes work best when you read actively. Keep a pen and a rough notebook beside you, cover the formula or diagram, and try to write it yourself before you look.

Draw the output waveform before writing any formula. It tells you the limits of integration and whether the output goes negative.
Keep one table for all rectifiers: average output voltage, whether inverter mode is possible, and the load type assumed.
For choppers, derive buck and boost outputs once from inductor volt-second balance, then use the results directly.
Write the three-phase 180° mode switching table and draw one phase and one line voltage from it.

In the last week, read only the formula boxes and exam tips, and solve one numerical or long question per unit from memory. If you study with friends, ask each other to explain one diagram or derivation aloud. Explaining a topic is the fastest way to find the gaps in it.

A short revision plan

If your exam is about a week away, this plan covers every unit in the PDF once and leaves time for practice. Stretch it over two weeks if you are starting from scratch.

Day 1: Introduction and Power Devices, Thyristor (SCR).
Day 2: Phase-Controlled Rectifiers, DC-DC Converters (Choppers).
Day 3: Inverters, AC Voltage Controllers and Cycloconverters.
Day 4: Applications.
Day 5: Solve the practice questions in the exam focus section below, one per unit, without the notes.
Day 6: Read only the formula boxes and exam tips, redo the numericals you got wrong, and sleep early.

Common mistakes to avoid

Using the R-load formula for a highly inductive load. With continuous current, the output can go negative over part of the cycle.
Using line voltage where phase voltage is needed in three-phase converter formulas. 1.35 VL is for the full converter with line voltage.
Forgetting that the boost output rises sharply as D approaches 1 in the ideal formula, but real losses limit it.
Mixing up latching current (needed to turn on) and holding current (needed to stay on).

How Power Electronics links to other subjects

Power Electronics builds on Electronic Devices and Network Analysis. It is the base for Electric Drives, HVDC and FACTS in Power Systems, and electric vehicle and renewable energy electives.

Exam focus: high-weightage topics

University papers usually give the most weight to SCR characteristics and protection, phase-controlled rectifiers with RL loads, buck and boost converters, three-phase inverters and PWM. GATE EE power electronics questions are mostly rectifier average and RMS voltage, input power factor, buck and boost ripple and inverter harmonics.

Typical long and numerical questions to practise:

Draw and explain the V-I characteristics of an SCR, and define latching and holding current.
What is a snubber circuit? Explain dv/dt and di/dt protection.
Derive the output voltage of a single-phase full converter with RL load and explain inverter mode.
Derive the output voltage of buck and boost converters and find the inductor ripple.
Explain a three-phase VSI in 180° mode with waveforms.
Explain sinusoidal PWM and define modulation index.

When you write a long answer, start with a one-line definition, draw the diagram or circuit, write the derivation in clear steps and end with the final result and its unit. For numericals, write the formula first, then substitute, so you can still earn step marks if the arithmetic slips.

These are practice questions based on common syllabus topics. They are not verified past papers, and we do not claim any question will appear in your exam. For real previous papers, use your university's official archive.

Who these notes are for

These notes are for B.Tech EE, EEE and ECE students preparing for their Power Electronics semester exam, and for students revising GATE EE basics such as rectifier voltages, buck and boost ripple and SCR basics. They are also useful before interviews for drives, EV, solar inverter and power supply roles, where converter basics are asked.

Download Power Electronics Handwritten Notes PDF