Chapter Overview

Control of loads is an important application area. For example, a control circuit may be used to accurately set and maintain the speed of a motor. Lights and heating elements can also be regulated with control circuits. The adjustable resistor, or rheostat, can be used to control loads. This chapter describes solid-state control devices and circuits that work much more efficiently than rheostats. It also shows how feedback can be used in control circuits.

This chapter will help you to:

1. Calculate efficiency in control circuits.

2. Identify the schematic symbols for thyristors.

3. Explain the operation of thyristors.

4. Define conduction angle in thyristor circuits.

5. Explain commutation in thyristor circuits.

6. Discuss servomechanisms.

7. Troubleshoot control circuits.

Study Outline

14-1 Introduction

14-2 The Silicon Controlled Rectifier

14-3 Full-Wave Devices

14-4 Feedback in Control Circuitry

14-5 Troubleshooting Electronic Control Circuits