Electrical switches work according to a basic design. The most common switches are the on/off toggle ones. Three-way and dimmer circuits are similar in design. Three-way circuits consist of two separate switches that control the same device, while a dimmer circuit controls only the amount of electricity that passes. Electric circuits work when electricity can move in a continuous loop. The electricity cuts off once the circle is broken. This is where the switch comes in. A toggle on/off circuit breaks the current when it is off. The current or loop completes itself when it’s in ” on ” position.