Importance of relay in switches

<font size=5><font color=#000033>Relays are the electromagnetic </font>switches</font>. Relays which come in assorted sizes, ratings, and applications, are used as remote control switches. Relays are remote control electrical switches that are controlled by another switch, such as a horn switch or a computer as in a power train control module. Relays allow a small current flow circuit to control a higher current circuit. Several designs of relays are in use today, 3- pin, 4-pin, 5-pin, and 6-pin, single switch or dual switches.
5.1 Relay Operation
All relays operate using the same basic principle. Our example will use a commonly used 4-pin relay. Relays have two circuits: A control circuit (shown in GREEN) and a load circuit (shown in RED). The control circuit has a small control coil while the load circuit has a switch. The coil controls the operation of the switch.