Editing Force (section)

===Tactile===
Tactile switches use an uneven force curve. Quality (mechanical) tactile switches use build-up and then a fall in resistance to indicate where the switch actuates. Membrane [[rubber dome]] switches maintain this same force curve, but for operator satisfaction alone: the force curve has no bearing on actuation as membrane dome switches actuate on bottoming out.

[[File:Force graph--tactile--Cherry MX Brown.svg|326px|centre]]

Many tactile switches also emit an audible click during actuation; such switches are referred to as "[[:Category:Clicky switches|clicky]]", with "[[:Category:Tactile switches|tactile]]" generally referring to a switch that has a tactile force curve but no audible feedback upon actuation. There are also keyboards that produce audible feedback for linear switches, using a relay or small speaker.

[[File:Force graph--clicky--capacitive buckling spring.svg|326px|centre]]

The [[Datanetics elastic diaphragm array]] actuator patent cites two reasons for the switch having a tactile force curve:

#To provide "unconscious assurance that the key stroke or displacement has been adequate for actuation"
#To "urge the key away from the exact point of actuation to prevent hovering at this stroke position which could cause switch jitter and unintended multiple actuation"

[[Cherry MX Brown]] in particular is noted for its weak tactility, but the patent in question (US 3773997) suggests that tactility does not have to be consciously observed.

The patent also suggests a role for a tactile force curve that is not related to the operator: to prevent the key from being accidentally held at the point of actuation (risking jitter), as an alternative to [[hysteresis]].

See: [[:Category:Tactile switches|Tactile switches]]