padswitches

Padswitches are electrical switches that operate when two conductive pads are brought into contact, completing an electrical circuit. They are commonly used in compact control panels, touch interfaces, and membrane assemblies where a low-profile, inexpensive switch is required.

Construction varies, but most padswitches consist of at least two conductive pads on closely spaced surfaces, separated by a dielectric layer or by a compressible spacer. Actuation can be achieved by pressing a rubber or silicone sheet with carbon-impregnated contact pads, a metal dome that deforms to bridge pads, or a flexible printed circuit that collapses to connect the pads. Some designs use capacitive sensing rather than direct contact, distinguishing them from true contact pads.

Operation is typically momentary; pressing closes the circuit and releasing returns it to the open state. They can be normally open or normally closed depending on pad layout and bias. Electrical characteristics include contact resistance in the ohms range when closed, and endurance ratings determined by the mechanical parts and pad wear.

Applications include consumer electronics keyboards and remote controls, medical devices, and industrial control panels where a flat, robust switch is required. Padswitches can be designed for single-use or high-reliability use, with considerations for wear, contamination, and environmental sealing.