Editing Metal contact switch (section)

===Negative and positive action===
<!-- If someone can find better terminology for this, especially real industry terminology, please rename this section! -->
At rest (when the switch is open) the contacts are held apart. As the switch is closed, the contacts are brought together. The contacts can either close of their own accord, or they can be pressed together under operator action. The majority of contact designs isolate the actions of the operator from the contacts: operating the switch removes whatever object was holding the contacts apart ("negative action"), and they close under their own power. Negative action was chosen by [[Cherry]], [[MEI]], [[SMK]] and various other manufacturers. Seldom mentioned, this approach is specifically referenced by [[MEI]] in their [[:File:MEI T-5C and T-5L specification.pdf|catalogue description of the T-5 series]] (name and date of publication lost):

:Switching action is accomplished by movement of one gold plated bar against another at right angles (classic cross bar switching). The bars strike with a velocity determined only by spring forces and not subject to the speed at which the switch plunger is struck. This type of design provides a much more constant and lower contact bounce than is found in mechanical contact switches of more conventional design. The effects of operator differences are substantially eliminated.

Likewise, [[Hi-Tek Dovetail Series]] switches "{{sq|incorporate}} cantilevered contacts which are isolated from the switch dynamics, thus assuring that the contact pressure is independent of switch operations."

Some switch types, such as Alps [[Alps SKCC series|SKCC series]] and [[Alps SKCL/SKCM series|SKCL/SKCM series]], and switches inspired by them such as [[Omron B3G-S series]], use the slider to press the contacts closed ("positive action"). A heavy-handed operator is going to be causing the switch contacts to close with more energy than an operator with a light touch.

Operator force is not the only suggested reason for the design. The 1973, 1974 and 1979 [[Cherry catalogues]] note the following in relation to [[Cherry gold crosspoint]]:

:Contacts are normally held apart for greatest shock resistance.<br>No microphonics or bounce during turn-off or at rest.

The patent for the [[PED keyswitch]] notes that the contacts are held apart to prevent inadvertent actuations due to impact. Unlike the [[Hi-Tek High Profile]] switch that may have inspired them, the contacts don't actually close under their own power and are pressed together via a funnel-shaped section of the slider. This switch combines aspects of both approaches: the contacts are both held apart at rest and closed by direct operator action.