12mm Momentary Push Button Switch

This is the basic tactile switch that shows up in nearly every electronics prototyping kit - a 4-pin through-hole momentary switch that closes its contact only while pressed, with a distinct mechanical click that gives clear physical feedback the moment the circuit is made. At 12mm across with a raised button head, it's noticeably easier to press accurately than the smaller 6mm switches common on breadboards, without being so large it wastes panel space.

Rated for 12V DC at 50mA, it's sized for switching logic-level signals rather than any real load directly - in practice that means it triggers a microcontroller input pin or a transistor/relay stage, not a motor or light directly. The four-pin footprint mounts flush on a standard breadboard or through a PCB, and the momentary (not latching) action means the circuit returns to its resting state the instant the button is released.

Common uses are reset buttons on Arduino and other microcontroller projects, manual trigger inputs for testing and debugging, and general-purpose momentary controls in any project needing a simple, tactile push-to-make button.