Pulse Circuits Tutorial

In electronics, a Pulse Circuit is a type of electronic circuit used for performing functions like waveform generation, wave shaping, switching, and modulating pulse signals. Pulse circuits are crucial part of most digital systems. Today, these circuits are widely being used in a number of fields like communication systems, digital electronic systems, signal processing systems, modern computing devices, etc.

This tutorial on Pulse Circuits is meant for explaining all the important electronic circuits that are related to pulse signals. In addition, we also cover the circuits that generate and work with pulse signals.

What is a Pulse Circuit?

A pulse circuit is nothing but an electronic circuit that operates with pulse signals. There are various types of pulse circuits designed and used for producing and manipulating electric pulse signals.

It is important to note that pulse signals are different from continuous signals like sinusoidal waves. Instead, these signals occur in a very short period of time and have a certain pulse width. Thus, pulse signals have the sharp rise and fall times. Pulse circuits work by varying the shape, amplitude or duration of these pulse signals.

Characteristics of Pulse Signals

A pulse signals has the following important characteristics −

Rise Time − It is denoted by T_r and is defined as the time taken by the pulse signal to rise from 10% to 90% of its maximum value.
Fall Time − It is denoted by T_f and is defined as the time taken by the pulse to fall from 90% to 10% of its maximum value.
Pulse Width − It is the duration for which the pulse signal has its maximum value and is denoted by T_pw.
Duty Cycle − It is defined as the ratio of pulse width to the total time period of the pulse waveform. It is often expressed in percentage.

Types of Pulse Circuits

Depending on the function and operation, the pulse circuits are broadly classified into the following main types −

1. Waveform Generators

These pulse circuits are used to produce pulse signals or waveforms of desired amplitude, frequency, and waveshapes. Multivibrators are common examples of waveform generators.

2. Pulse Shaping Circuits

These pulse circuits are designed and used for modifying waveforms of pulse signals to meet the application requirements. Common examples of pulse shaping circuits include clippers and clampers.

3. Switching Circuits

These pulse circuits are designed and used for providing fast on/off switching operations in electronic systems. Examples of pulse switching circuits include transistor as a switch, diode as a switch, etc.

4. Modulation Circuits

The pulse circuits which are designed for modifying the parameters of pulse signals for applications like pulse-width modulation are called modulation circuits.

Applications of Pulse Circuits

Pulse circuits find their applications in a variety of fields. Some of the common examples are given here −

In digital electronic systems, pulse circuits are used to provide timing and clock signals in processors.
Pulse circuits are used in communication systems for applications like data encoding, pulse code modulation, etc.
Pulse circuits are also employed for wave shaping and signal conditioning in signal processing applications.
Control systems also use pulse circuits to produce pulse-width modulated signals to control the speed of electric motors.
In testing and measuring instruments like oscilloscopes and signals analyzers, pulse circuits are used to generate test signals.

What You Will Learn in Pulse Circuits?

This tutorial explains a wide range of pulse circuits and their applications. All the topics covered in this tutorial are listed in the following list −

Pulse Circuits - Singal − This chapter defines electronic signals, pulse signals, and important terms related to pulse signals.
Pulse Circuits - Switch − This chapter provides an overview of different types of switches along with their advantages and disadvantages.
Transistor as a Switch − In this chapter, you will understand the operation of a bipolar junction transistor as a switch.
Multivibrator Overview − This chapter is meant for explaining what is a multivibrator and its types.
Astable Multivibrator − This section explains the construction, working, and applications of astable multivibrator.
Monostable Multivibrator − In this section, you will learn about construction, working, and applications of monostable multivibrator.
Bistable Multivibrator − In this chapter, you will find a discussion on bistable multivibrator, its construction, operation, advantages, and applications.
Time Base Generators Overview − This chapter provides a description of time-base generator and its applications.
Types of Time Base Generators − This section explains two different types of time base generators namely, voltage time base generator and current time base generator.
Bootstrap Time Base Generator − This chapter is meant for explaining the construction, working, and advantages of bootstrap time base generator.
Miller Sweep Generator − In this section, you will learn about construction, operation, and applications of miller sweep generator.
Unijunction Transistor − This chapter provides an overview of construction, working, and characteristics of unijunction transistor (UJT).
UJT as Relaxation Oscillator − In this chapter, you will understand how a UJT works as a relaxation oscillator and where it is used.
Pulse Circuits - Synchronization − This chapter is for explaining the concept of synchronization and different types of synchronizations used in pulse circuits.
Blocking Oscillators − In this section, you will learn about different types of blocking oscillators.
Sampling Gates − This chapter describes sampling gates and their types.
Unidirectional Sampling Gate − This chapter explains construction, working, advantages, and disadvantages of unidirectional sampling gates.
Unidirectional with More Inputs − In this chapter, you will learn about unidirectional sampling gate circuits that can handle more than one input signals.
Bidirectional Sampling Gates − This chapter discusses about different types of bidirectional sampling gates along with their applications.

Who Should Learn Pulse Circuits?

A reader who is interested in the basics of pulse and sweep related circuits and who aspires to have an idea regarding the generation and applications of pulse and sweep signals, can go ahead with this tutorial. This tutorial is also a useful resource for any of the following −

Students and learners in electronics and communication engineering.
Anyone who have interest in electronic projects.
Engineers and technicians working in the field of electronics, signal processing, automation, control, and embedded systems.
Educators who teach pulse circuits in academics.

Prerequisites to Learn Pulse Circuits

As pulse circuits are the applications of electronic components and circuits. Thus, we assume that the readers have prior knowledge of the fundamental concepts of Basic Electronic Circuits and the behavior of different electronic components. Also, a basic understanding of Signals and Systems and Network Theory concepts will be very helpful for understanding the topics covered here.

FAQs on Pulse Circuits

In this section, we have picked up some of the most Frequently Asked Questions (FAQs) on Pulse Circuits, followed by their answers.

A pulse circuit is an electronic circuit specially designed to generate, modify, and process pulse signals for a number purposes like timing, clock signaling, digital logic processing, etc.

There are a variety of electronic components that used for implementing pulse circuits. Some common of them are resistors, diodes, transistors, inductors, capacitors, and some special ICs.

A monostable multivibrator has only one stable state and its other state is termed as unstable or transient state. When a trigger pulse is applied to the monostable multivibrator, it enters into the transient state and comes back to the stable state after the trigger pulse is completed.

Both pulse width and duty cycle are two important parameters of a pulse signal, but they are different from each other. Pulse width is defined as the duration of a pulse signal for which the signal remains in its maximum level, while duty cycle is defined as the ratio of pulse width to the total duration of the pulse waveform.

Pulse circuits are mainly designed for and used in digital systems, but they are also used in certain analog systems employed in applications like modulation, signal conditioning, etc.

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