Video explanation
Three cutaway switches show stem travel, spring compression and contact actuation, with synchronized displacement and force readouts.
Travel and actuation
A key can actuate before bottoming out. The moving stem operates a contact mechanism at the actuation point.
Spring return
Pressing stores elastic energy in the spring. Releasing the key lets it return the stem, while spring characteristics affect feel.
Motion becomes input
Keyboard electronics read switch states and handle contact bounce. The model’s millimeter and centinewton readings do not describe every switch.