Total travel is normally between 2.5 and 4 millimetres. Travel refers to the vertical motion of a key, and the range of this motion. The subject of force covers how the force changes throughout the keystroke, and therefore what typing feels like. The force changes the further you press the key, and the rate of change may itself change. Within the subject of feel, there are some specific concepts:įorce refers to the force that you feel in your finger when pressing a key. The keys may feel heavy or light, and they may exhibit a lot of friction or be very smooth. The term keyfeel refers to how a type of keyboard or switch feels to type on. While the term is unlikely to fade out any time soon, take note that its meaning is not defined. Metal contact keyboards are not inherently high quality, and high quality keyboards are not all metal contact, such as the Model M previously mentioned, and the various electromagnetic sensing methods that typically offer greater longevity than physical switch mechanisms.
Tactile vs linear vs clicky series#
The Model M series is membrane, which should disqualify it from being classed as mechanical. However, one of the best-known "mechanical" keyboards is the IBM Enhanced Keyboard, better known by its series name, of IBM Model M. The term "mechanical" is used by some manufacturers to metal contact switches: that is, switches where the electric current passes through a sprung piece of metal that is pressed against another piece of metal.
Tactile vs linear vs clicky software#
The increased affordability of microprocessor-driven equipment has removed the necessity of more complex switch configurations for keyboards, as the software takes care of the machine state, but other (non-computer) equipment may also find a use for switches other than SPST NO. The latter will function as the former if the input terminals are connected at the PCB. Some switches have three terminals to provide changeover action (current is diverted from one circuit to another), or four terminals where one pair of contacts is normally open and the other is normally closed. Some are found to have four terminals for DPST, and some are found to have four terminals for two-stage action. As time passes, and more specifications are acquired, the nature of switches become clear. In some cases, switches clearly support four terminals, but are seldom if ever seen with the second pair of holes populated, with the available factory configurations left as a mystery.
These are not generally found in keyboards, but Micro Switch SD Series switches are known for having redundant sense lines. Here, a single switch with a single plunger connects two separate circuit paths at once this is called double pole single throw (DPST).
Redundancy can be provided with a second pair of terminals. These are more likely to be found in electric typewriters. Such switches were used for lock keys in the 70s and early 80s, after which they went out of fashion, with Apple being the last prominent manufacturer to use them, up to the Apple Extended Keyboard II.ĭouble action or two-stage switches connect two circuit paths in sequence, with the second connection made after the key is pressed further. NO is also called form A, and NC is also called form B.Īlternate action switches (also latching action or push-push) will stay down when pressed to release them, they must be pressed a second time. Normal switches will connect a single circuit pathway, or provide only one of some other form of sensing such a switch is called single pole single throw normally open (SPST NO). Normal switches are called momentary, as they typically are only closed (connected) for a moment, and will open (disconnect) when you let go.
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