This page will look at some of the main components you will have come across on your course and will need to get to grips with before the exam. Switches Resistors Resistor colour code Capacitors Sample exam question Start here 1. Switches Switches are used to connect or disconnect a circuit. They can have different numbers of poles and throws . Poles are the number of connections a switch can make.
Throws are the number of positions to which the poles can be switched.
There are four main types of mechanical switches that you could use in circuits. The description given to these depends on the function of the switch. The single throw switches are either open or closed. Double pole single throw switches are often used in mains circuits to disconnect or isolate a connection. The double throw switches are used to change from one part of a circuit to another.