A keyswitch is tactile if it has a bump in its response to finger pressure at or near the engagement point where the keypress registers and before the key bottoms out at the end of its travel. A keyboard is tactile if it is made with tactile keyswitches.
The trajectory of a keyswitch from the top (when a finger begins pressing) to the bottom when it reaches its mechanical limit. Travel distance is usually between 2 and 5 mm.
The opposite of tactile. A linear keyswitch produces constant resistance until it stops at the end of its travel.
More at Source: Keyswitch in Mechanical Keyboard Guide
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