Introduction to Switches

 At the end of this lesson, you will be able to identify common types of electrical switching devices and describe the principles of their operation. • Explain the purpose of an electrical switch • Identify the various types of electrical switches • Describe variations and operating principles of throw and pole switches • Explain the difference between mercury and reed relay switches • Describe the operation of mercury, reed relay, float, pressure, limit, flow, pushbutton, selector, and drum switches • Describe the operation of joysticks • Identify the operating principles of interlock switches • Explain the purpose and operation of safety switches