In our day-to-day lives, how often do we encounter switches? Switches can be seen everywhere. For electronic and electrical system, they act as a physical interface to the real world. Be it a key of a keyboard or mobile or be it a knob on an electrical appliance or be it a miniature button used on the PCBs of embedded systems or be it a circuit breaker used on the power lines- all these are switches. We are in continuous interaction with switches without bothering about the manner it functions behind the scene?Switches are of different types, of different specifications and are selected and used in a particular application according to specific requirements. Subsequent sections will discuss the switches in detail.