Now that you understand how to design and construct a basic circuit you can begin to think about how to control it.
A switch is something that enables, prevents, or diverts the flow of electricity. It creates or breaks the physical connection of two conductors. Familiar switches include a standard toggle switch that controls the lighting of a room, the slide switch on the barrel of a classic flashlight, or even the blinking red, “DO NOT TOUCH” button on the control panel of a spaceship. And when you put your imagination to use you can create switches in forms that you wouldn’t expect.