dPdt

DPDT stands for double-pole double-throw. It is a type of mechanical switch that controls two separate circuits with a single actuator. Each pole provides one common terminal that can connect to one of two throw terminals, allowing two independent connections to switch in tandem. Because two poles are operated together, a DPDT switch effectively performs the function of two SPDT switches with a single lever or actuator. The typical configuration yields six terminals arranged as two rows of three.

In operation, each common terminal is connected to one of its two throws depending on the actuator position. Some variants include a center-off position, yielding DPDT center-off or DPDT ON-OFF-ON, where neither common is connected in the center position. Latching versions hold their position without continuous actuation.

Common configurations include on-on, where each pole routes to a different output depending on position; and on-off-on, which provides two active positions separated by an off state. DPDT can be wired to reverse the polarity of a DC motor by swapping the two supply leads, or to switch two separate signals in unison. It is frequently used in electronic devices, control panels, and in audio and guitar pedal circuits for signal routing, as well as for true bypass switching in effects units.

When wiring, one must observe the pinout and ensure that the common terminals are correctly identified. Mounting style, actuator type (rotary, sliding, toggle), and terminal layout vary by manufacturer, but the fundamental function remains the same: two independent circuits switched together by a single action.