What Are Keyboard Switches and How Do They Work?
DashanYuan
Press a key. Something happens inside the switch, and a letter appears. This article is about that "something" — the actual mechanical and electrical sequence that turns a finger press into a keystroke.
Looking for the broader introduction instead — what the types are and which to buy? Start with what are keyboard switches.
The Four Parts of a Keyboard Switch
Every mechanical keyboard switch is made of the same four components. Everything else is a variation on this.
| Part | Role |
|---|---|
| Upper housing | The lid. Guides the stem and holds the assembly together. |
| Stem | The coloured plastic piece that moves. Its shape decides the feel. |
| Spring | Resists the press and returns the stem to the top. |
| Metal contact leaves | Two strips of metal that touch to complete the circuit. |
All four sit in a bottom housing, which also holds the switch's pins — the metal legs that connect it to the keyboard's circuit board.
What Happens When You Press a Key
The sequence takes a few milliseconds:
- You press down. The keycap pushes the stem into the housing.
- The spring compresses. Resistance builds gradually — this is what you feel as the switch's "weight".
- The stem clears the contact leaf. As the stem descends, a notch in its side lets the metal leaf spring inward.
- The circuit closes. The two leaves touch. This is actuation — the moment the keystroke is registered, typically around 2 mm down.
- You bottom out. The stem hits the base of the housing. This is optional — the key already registered — but almost everyone does it.
- You release. The spring pushes the stem back up, the leaves separate, and the circuit opens.
The important insight: the key registers before you finish pressing it. Actuation happens partway down, not at the bottom. Light typists can learn to type without bottoming out at all, which is quieter and less tiring.
How the Stem Shape Changes Everything
Step 3 above is where the three main switch types diverge — and the only thing that differs between them is the shape of the stem.
- Linear — the side of the stem is a smooth rail. The leaf slides along it with no drama. Result: a completely smooth press.
- Tactile — the stem has a raised bump. The leaf has to be pushed over it, requiring extra force for a moment. Result: the bump you feel.
- Clicky — same bump, plus a separate loose piece (a click jacket or click bar) that snaps audibly. Result: the bump plus a deliberate click.
Same mechanism, same circuit, one differently shaped piece of plastic. That is genuinely the whole difference between switch types.
How Switches Make Sound
A switch makes noise at two impacts: the stem hitting the bottom housing on the downstroke, and the stem hitting the upper housing on the return. Both are plastic-on-plastic.
Which is why materials matter so much. Harder, fiberglass-reinforced housings produce a brighter, higher-pitched sound; softer housings and stems produce a deeper, more muted one. Shop by the result: clacky, thocky and creamy, or deep sounding.
Silent switches attack this directly, adding dampening pads to the stem so those two impacts are cushioned.
Magnetic Switches Work Differently
Hall effect switches skip the metal contacts entirely. The stem carries a small magnet, and a sensor on the circuit board measures how close it is. Because the board reads a continuous distance rather than an on/off contact, you can set the actuation point in software — and change it per key.
See how Hall effect keyboards work or browse Hall effect switches.
Why This Matters When Buying
Once you understand the mechanism, spec sheets stop being intimidating:
- Actuation force (g) — how strong the spring is at the moment of actuation.
- Actuation distance (mm) — how far down the leaves touch. Shorter means faster registration.
- Total travel (mm) — how far the stem moves before bottoming out.
- Stem / housing material — the main determinant of sound.
Ready to choose? Our mechanical keyboard switch types guide walks you through it step by step.
Frequently Asked Questions
How do keyboard switches register a keypress?
The stem moves down, allowing two metal contact leaves inside the switch to touch. That closes an electrical circuit, which the keyboard's controller reads as a keystroke. It happens partway through the press, not at the bottom.
What is actuation point?
The depth at which the key registers — typically around 2 mm on a standard mechanical switch. On magnetic switches it is adjustable in software.
Do I need to press the key all the way down?
No. The key registers at the actuation point. Bottoming out is a habit, not a requirement, and avoiding it makes typing quieter and less tiring.
Why do two switches with the same specs sound different?
Because sound comes from the plastics, not the numbers. Housing and stem material determine the pitch and fullness of the sound far more than actuation force does.