Dimmer switches, or otherwise known as rheostats, are devices that are connected to light sources and are used to decrease or increase their brightness. This is achieved by decreasing or increasing the voltage, which consequently affects the intensity of the light. Although dimmers are used for various purposes, the term is mainly intended for those that control lighting. The number of poles of a panel switch corresponds to the number of circuits it can control. Thus, a monopole switch can control the power supply to one circuit, a bipole to two, etc. See full description