A switch is designed to control the lights, fans and other various appliances in the home like a disposal. They come with a simple opening and closing mechanism that supplies and shuts the connection in an electrical circuit. When the switch is opened, the connection between the two terminals is cut, and the flow of electricity is stopped. Thus, the light attached to it is turned off. When the switch is closed, the light attached to is turned on. This is because the closing allows the terminals to establish contact and enable the electric current to flow into the circuit.