Principles of Transistor Circuits, 9th Edition

Chapter 13

Pulse generators

Introduction: the transistor as a switch

So far in this book we have discussed the use of transistors as amplifiers of pulses or sinusoidal signals. In class-A and class-B amplifiers the transistor is used as a linear amplifier in which every change in input signal brings about a corresponding change in output signal. In this type of operation (typical of analogue equipment) the shape of the input–output characteristic is all-important and any deviations from linearity must be compensated by negative feedback or other means to give an acceptable performance.

In pulse or digital circuits, however, transistors are used in a completely different type of operation in which the shape of the input–output characteristic is of ...