Sinusoidal Oscillators Tutorial

Sinusoidal Oscillators Tutorial

In electronics, Sinusoidal Oscillators are electronic circuits which designed and used to generate period signals, having a sinusoidal waveform. Sinusoidal oscillators basically work by converting the input energy from a DC source into a sinusoidal waveform AC output.

Most sinusoidal oscillators are capable of producing a sinusoidal output of frequencies between 20 Hz and 1 GHz. A typical sinusoidal oscillator consists of two main components namely, an amplifier and a feedback mechanism. Due to the presence of feedback mechanism, the sinusoidal oscillators have a loop gain of greater than or equal to unity. These oscillators provide a total phase shift of either 0° or 360° around the loop.

Sinusoidal oscillators are the main components in a wide range of electronic systems, where smooth sine wave signals are required. These systems can range from small home appliances to large communication systems.

In this tutorial, you will learn about the important features of different types of sinusoidal oscillators, starting from their basic working principle to their circuit arrangement and behavior.

What is an Oscillator?

An oscillator is an electronic circuit that designed to generate output signals of certain waveforms without taking any external input signal. For generating output signals, an oscillator uses energy from a DC source. Depending on the needs of application, oscillators can produce different types of waveforms such as sinusoidal, square, or triangular. In devices like radios, computers, signal processors, clocks, etc., oscillators act as a crucial component.

Some of the important characteristics of oscillators are highlighted here −

• Oscillators can generate an output waveform without any external signal input.
• Oscillators can provide frequency stability and produce consistent waveforms.
• Oscillators can provide different types of waveform shapes like sinusoidal, square, triangular, etc.

What is a Sinusoidal Oscillator?

A type of oscillator that can produce a continuous, smooth waveform of sinusoidal (sine or cosine) shape is called a sinusoidal oscillator. Basically, a sinusoidal oscillator converts the energy from a DC source into a sinusoidal AC output.

Sinusoidal oscillators are known for their capability of producing sine wave signals with fundamental frequency and minimal harmonic distortion. Hence, these oscillators are widely used in applications where stability and precision are critical like in audio devices and communication systems.

Block Diagram of Sinusoidal Oscillator

The following figure shows the block diagram of a typical sinusoidal oscillator −

It consists of the following main components −

• Amplifier − It is responsible for boosting the signals so the oscillator can maintain the oscillations. It also compensates the energy losses in the system.
• Feedback Network − This component provides some part of output signal back to the amplifier input. It is responsible for phase correction, frequency selection, and stabilization of oscillations generated by the oscillator.

Sinusoidal Oscillator Working Principle

The working of a sinusoidal oscillator is dependent on conversion of energy from a DC source into sinusoidal AC output with positive feedback. The step-by-step explanation of working of a sinusoidal oscillator is given here −

Step 1 − First of all, the sinusoidal oscillator takes energy from a DC source to start the oscillation process.

Step 2 − Then, it performs amplification of signals to sustain the oscillations and shape the output waveform in the sinusoidal form.

Step 3 − Next, the feedback network comes into action. It keeps feeding some portion of the output back to the amplifier input to ensure the correct phase around the loop and maintain amplitude of the output signal.

Types of Sinusoidal Oscillators

Depending on the circuit design and frequency range, sinusoidal oscillators can be classified into several different types.

Some of the main types of sinusoidal oscillators and their characteristics are given in the following table −

Applications of Sinusoidal Oscillators

Sinusoidal oscillators find their applications in a wide range of electronic systems. Some common examples of sinusoidal oscillator applications are given here −

• In communication systems, sinusoidal oscillators are used to produce reference and carrier signals for amplitude or frequency modulation.
• In test equipment, sinusoidal oscillators are used for generating test signals.
• Sinusoidal oscillators are also employed in audio systems for applications like sound synthesis or tone generation.

What You Will Learn in This Sinusoidal Oscillators Tutorial?

This tutorial is designed to explain some important concepts of sinusoidal oscillators, starting from their basic construction and working to their applications in a variety of circuits and systems. The topics covered in this tutorial are described in the following table −

• Sinusoidal Oscillators Introduction − This chapter provides an overview of sinusoidal oscillators and their applications.
• Sinusoidal Oscillators - Basic Concepts − This chapter describes some basic concepts of sinusoidal oscillators like tank circuit, frequency of oscillations, etc.
• Oscillator Circuit − In this section, you will understand the construction and working of a practical oscillator circuit.
• Tuned Circuit Oscillators − This chapter discusses about basics and types of tuned circuit oscillators.
• Hartley Oscillator − This chapter is meant for explaining the construction, working, and applications of Hartley oscillator.
• Colpitts Oscillator − In this chapter, you will learn about the construction, working, and applications of Colpitts oscillator.
• Clapp Oscillator − This section explains the circuit diagram and operation of Clapp oscillator.
• Phase Shift Oscillators − In this chapter, you will find a discussion about phase shift oscillators and their principle.
• Wien Bridge Oscillator − This chapter discusses the construction, working, and advantages of Wien bridge oscillator.
• Crystal Oscillators − In this section, you will explore the basics to advance concepts of crystal oscillators.
• Negative Resistance Oscillators − This chapter provides an overview of negative resistance property and negative resistance oscillators.
• Tunnel Diode Oscillator − This chapter describes the circuit, working, and characteristics of tunnel diode oscillator.

Who Should Learn Sinusoidal Oscillators?

This tutorial will be useful for all those readers who want to learn the basic principles of sinusoidal oscillators and oscillator circuits. It is primarily designed for readers or learners belonging to the following categories −

• Students of electrical and electronics engineering
• Engineering professionals working in the field of circuit design and signal processing.
• Professional working in communication and electronic measurement domains, etc.

Prerequisites to Learn Sinusoidal Oscillators

This tutorial on Sinusoidal Oscillators is intended for beginners in the field of Electronics and Communication Engineering. However, sinusoidal oscillator is an application of electronic circuits and components. Hence, we assume that the readers have a basic knowledge of the fundamental concepts of Basic Electronic Circuits and the behavior of different electronic components.

FAQs on Sinusoidal Oscillators

In this section, we have collected some of the most Frequently Asked Questions (FAQs) on Sinusoidal Oscillators, followed by their answers.

1. What is the basic principle of Sine Wave Oscillator?

The basic principle of sine wave oscillator is to produce an output signal having a sinusoidal waveform. For this, it uses the concept of positive feedback and Barkhausen Criterion.

2. What is the working principle of an Oscillator?

The working of an oscillator is based on the principle of positive feedback and signal amplification. According to this principle, a portion of the oscillatory output signal is sent back to the input of an amplifier as a feedback signal to ensure desired frequency and waveform of the output signal.

3. What is the difference between a sinusoidal and non-sinusoidal oscillator?

The main difference between a sinusoidal and non-sinusoidal oscillator is in their waveform of the output signal.

A sinusoidal oscillator is one that generates an output signal having a sine or cosine waveform, whereas a non-sinusoidal oscillator is one that generates an output signal which can have a waveform other than sinusoidal shape like square, triangular, sawtooth, etc.

4. What is the Barkhausen Criterion?

The Barkhausen Criterion is a mathematical requirement that predicts whether an electronic circuit will oscillate or not. It comprises the following two important conditions −

• The loop gain must be equal to one in absolute magnitude.
• The phase shift though the loop must be either 0 or an integer multiple of 2π.

5. What does a sinusoidal oscillator do?

A sinusoidal oscillator converts energy from a DC source into an AC signal of certain frequency and sinusoidal waveform.