Switch (mechanical keyboard)
A switch sits between the barebones mechanical keyboard itself, and each keycap that you actually press. It's responsible for completing the appropriate circuit whenever you press a key.
Unlike with more common membrane keyboards, mechanical keyboards' switches usually don't require you to press the key all the way down. Most register each keypress about halfway down, with any further movement being purely optional. Mechanical keyboard users even have a term for pressing their keys all the way down, "bottoming out".
Modern mechanical keyboard switches were designed by Cherry as the Cherry MX switches range. Once their patent expired, other companies such as Gateron and Kailh cloned them, turning them into a de facto standard. This includes not just their shape and operation, but even their arbitrary colour coding.
Switches came in three broad varieties:
- Linear (smooth)
- Tactile (bumpy)
- Clicky (loud)
Linear switches are smooth and quiet. You simply push the button down, meeting consistent resistance throughout. They give no indication of when you've pushed them far enough to register a keypress. They're often red.
Tactile switches give you a little bump of resistance to indicate that the keypress is registered. This is reasonably quiet, but you can feel it. They're often brown.
Clicky switches let you, and everybody within earshot, know exactly when you've pressed a key. They're a fun choice for anyone who works from home, is single, has no pets, and lives in a detached house. They're often blue.
Within each of these three types, there are various different combinations of operating force and travel distance available, each distinguished by a unique colour (with some of the more exotic ones running out of colours and naming them after animals, fruit, and other assorted sundries). Newcomers to mechanical keyboards can rest assured that sticking to the main red, brown, and blue options is sufficient for most people.
As clicky switches will likely annoy everyone within earshot, the main choice is between linear (smooth) and tactile (bumpy) switches. Linear switches are generally preferred by gamers, while tactile and clicky switches are generally preferred by typists.
Technical notes
Cherry MX switches are measured in centinewtons of operating force, and millimetres of travel. Almost all their clones are instead measured in gram-force, but as 1 cN = 1.02 gf, for our purposes they're essentially synonymous. 80cN = 81.6 gf, a negligible difference... especially once you take into account that the tolerance is often up to about ± 15 gf.
Mechanical keyboards: Keychron keyboards | Southpaw | Switch (mechanical keyboard)
Switches: Cherry MX switches | Gateron MX switches | Keychron switches