What do the poles of a switch define?

The poles of a switch refer specifically to the number of separate circuits that can be controlled by that switch. Each pole represents an independent pathway through which current can flow, allowing for the control of multiple circuits from a single switch. This is critical in applications that require multiple circuits to be switched on or off simultaneously, providing versatility and functionality in various electrical setups.

Understanding the difference between poles and contacts is important because while poles indicate the number of circuits the switch can handle, contacts refer to the individual conductive paths that open or close the circuit when the switch is activated. Thus, a switch can have multiple contacts under each pole, but the number of poles directly defines how many circuits the switch can manage. This is a fundamental concept in understanding how switches operate within electrical and instrumentation systems.