Wiring

Piezo switches, which are often used for their durability and robustness in various applications, have a slightly different configuration compared to mechanical switches.

COM (Common): This wire is typically the ground or negative connection of the circuit. In the configuration of a piezo switch, COM serves as the reference point for the circuit's electrical current, essentially completing the circuit when the switch is activated.

FUNC (Function): This is the wire through which the activation signal is sent. When the piezo element is pressed, it generates a voltage that is sent through the FUNC wire.

This wire carries the signal to the rest of the circuit to trigger whatever action the switch is supposed to control, such as turning on a light or activating a door opener. When the switch is pressed, the piezo material inside generates an electrical charge due to mechanical stress (thanks to the piezoelectric effect). This charge travels through the FUNC wire, and if the circuit is completed by connection to the COM wire, the switch performs its designated function.