A two-way switch, or a Single Pole Double Throw (SPDT) switch, can be used as a selector to switch between two circuits or signal paths in devices ranging from electric guitars to car engines. Using a common terminal and a selector to reroute the signal of a circuit, the two-way switch can be found in almost all electrical applications. Wiring a two-way switch is fairly simple, provided you have a knowledge of the circuit you are working with and the proper tools.
Identify the terminals on your two-way switch. There will be three. The middle terminal is the common terminal, "C." The outer two terminals correspond with the same position on the selector. If the selector is set to the left, the left terminal is in operation. For the right side, the right terminal is in operation. Note these terminals as "A" and "B."
Determine how you would like to use the switch. A two-way switch can either take a single signal input and switch it between two possible signal outputs, or it can switch between two inputs and send them to a single output. In terms of an audio system, the switch could either take the amplifier signal and choose between two speakers, or it could choose from two amplifier signals and send them to a single speaker. Always be sure the power rating of your switch matches the current of your circuit.
Solder a wire from your circuit to the common terminal of your switch. This will be either your input or output signal.
Solder one end of a wire to terminal "A." Solder the free end of the wire to the corresponding point in your circuit. Repeat this process for terminal "B."
Power on your circuit and test to make sure the switch is properly switching between the two signal paths. If there are problems, check to make sure all of your connections are secure.
When working with electrical circuits, be sure they are disconnected from all power sources, including batteries, to avoid electrical shock. Keep both feet firmly grounded. Working with a soldering iron can produce high heat and toxic fumes. Work carefully in a well ventilated area to avoid injury.