Switch Anatomy

Housing

The housing includes the base housing and top housing.

The base housing has two pins that slot into the PCB. They need to be soldered in most cases—if a keyboard is “hotswap,” that means soldering isn’t needed.

Switches can be either plate mount or PCB mount: a PCB mount switch has two additional plastic legs that secure it into the PCB.

Stem

The stem sits within the switch housing and on the spring, while the ‘+’ extrusion locks into the bottom of a keycap. The two legs help determine the switch’s level of tactility as it comes into contact with the metal leaf.

Spring

The spring sits on the base housing pole and supports the stem’s vertical movement. Springs come in a wide range of weights, with heavier springs requiring more strength for a keypress.

Metal Leaf

When a switch is pressed, the stem presses into the metal leaf that sits in the bottom housing. The connection registers the keypress onto the PCB, allowing those magical symbols to show up on your computer.