4 - Oscillators

Summary

Objectives

At the end of the study of this chapter a student should be:

1. familiar with the conditions of sinusoidal oscillations

2. able to understand the principles of LC oscillators

3. familiar with the principle of operations of RC oscillators

4. able to construct crystal oscillators.

In electronics periodic signals of various shapes such as sinusoidal, triangular, rectangular and pulses are often needed to perform different types of operation. Although the term oscillator is generally referred to a generator of sinusoidal signals, while a rectangular-wave generator is more commonly known as a multivibrator, an oscillator generates an a.c. output signal without requiring any form of input signal. Sinusoidal oscillators are mainly used in radio frequency transmitters and receivers. Square-wave or pulse generators are used in almost every type of digital equipment. In this chapter we shall mainly concentrate on sinusoidal oscillators.