A motor reversing switch is a small electrical component that changes the direction in which an electric motor runs. Manually reversing a motor's direction requires changing the positive and negative wires that connect a system's battery to its motor. A motor reversing switch has two sets of connections that correspond to different positions for the battery cables. A motor reversing switch allows the user to change a motor's direction on-demand and without rewiring the motor and battery every time.
A motor reversing switch is a special type of switch called a double-pole, double-throw switch, or DPDT switch for short. The name refers to the fact that the switch has two different "on" positions, called throws, and two different sets of electrical connections. When the operator throws the switch to one "on" position, the motor runs forward, and when she switches to the other "on" position, the motor runs backward. A simple on-off switch is known as a single-pole, single-throw, or SPST, switch, as it only has a single set of electrical connections and only one "on" position.
Each motor reversing switch requires soldering to at least six different electrical connections. Because this can be tedious, particularly when wiring multiple motor reversing switches in a system, printed circuit boards are a useful alternative to DPDT switches. While printed circuit boards require special software and manufacturing equipment, they have much greater functionality than switches and require little, if any, soldering.