Switches are the mechanism used to detect when a user presses down on a key.
Rubber dome keyboards are your typical and most commonly found switch. Rubber dome keyboards contain a sheet of rubber with domes where keys are located. When the domes are pressed all the way down onto the keyboard's PCB, the keyboard registers a key stroke.
These are the most popular mechanical keyboard switches. There are a few different variations with different feels. Each type switch has a spring and a stem encased in a housing. The spring mainly determines the actuation force, while the stem provides different tactility to the switches. Different stems and springs allow for different feels catering for different preferences.
Switch animations courtesy of Castin "Lethal Squirrel" Cramer.
Actuation Force: 40g
With no tactility and the lightest of the springs, the red switch is the "lightest" of all the switches.
Actuation Force: 60g
This is a heavier version of the red switch, using a heavier spring but with the same linearity as the red switch.
Actuation Force: 50g (60g Peak)
Tactility: Tactile, Clicky
The blue switch has a very pronounced and audible click. You and others around you definitely can't miss the fact that you've pressed down a key.
Actuation Force: 45g (55g Peak)
The brown switch is like the red switch, but with a slight "bump" that provides feedback to the typer.
Actuation Force: 55g (65g Peak)
This switch is a heavier version of the brown switch. With a spring that is inbetween the black and brown's and a slightly larger "bump" when pressed.
Topre is a type of switch which is a hybrid of rubber domes with the inclusion of springs. However, they are of very high quality and gives one of the best typing experiences. The Topre switches give an even smoother and quieter feel than Cherry MX switches. Image from Topre.
Buckling Springs are used in the famous clicky IBM keyboards. They work by having a spring which when pressed down will suddenly bend (buckle) and close the electrical switch when enough force is applied. Image from here.
These are the plastic keys that go on top of the switches on your keyboards. There are a variety of materials used to make them and a different options for printing legends of them.
Different materials give a different feel when typing. Extensive use of keycaps lead to the surface to "shine" and different materials will be more durable to this. The type of material is very closely related to the printing process used.
This is the most commonly found plastic, especially for double-shot plastic. This material can typically found in most stock keyboards bought.
This material is more durable than ABS. Shine occurs much slower on the keys in comparison with ABS and is the material used for dye sublimated keys.
There are a variety of ways of creating the legends (letters and symbols) on the top of keycaps.
This is typically the most common printing found on rubber dome keyboards. This printing wears away over time as the legends are just material stuck to the surface of the key.
All our double-shot keys are made of ABS plastic. Double-shot legends are made of plastic and is embedded inside the key. Even over extensive use, the legend will never wear away. Unlike dye sublimated keys, double-shot keys can have light legends on dark keycaps.
Much like double-shot, the legends will never wear away. Our dye sublimated keys are printed on PBT plastic. The process uses a dye that reaches deep into the keycap, so that even if we wear off the surface of the key, the colors will never wear out. With dye sublimation we are not limited to the number of colors we can use unlike double-shot printing.
Key Roll-Over (KRO) is convention in which a number of keys on a keyboard may be pressed and registered on a computer. N-Key Roll-Over or NKRO, refers to all N of a keyboards keys being able to be pressed at once and detected on a computer. However you may also find 2KRO or 6KRO meaning 2 or 6 keys able to be detected at one time, the same principle applies to other numbers. This is typically what gamers need, as games may require more than one key to be pressed at one time.
Ghosting is when multiple keys are pressed, but extra (unpressed) keys are registered on a computer. This is obviously unwanted and is taken care of Anti-Ghosting. Most keyboards are designed with anti-ghosting.
Cherry MX Plate/PCB Mounting and Stabilizers
Plate Mounting has a metal plate which holds onto the body of the switches. This keeps them stable and reduces the amount of wiggling that the switches may do without it. However most plates will restrict the possibility of opening the switch without desoldering the switch from the PCB. However recent designs by the community allow for it.
When plate mounting, the stabilizers used for larger keys are usually going to be Costar stabilizers, which are arguably much smoother than the Cherry stabilizers on PCB mounted boards. Costar stabilizers are, however, make swapping the large keycaps a bit more difficult; albeit not by much.
Profiles and Row Numbering
Profiles refer to the shape and heights of the keycaps. Different profiles are intended for different rows. Each row has a different shape allowing for a curved and angled inclination of the keys on the keyboard, making it much more ergonomic. Different manufacturers may have different profiles, so keys may not fit and match among different manufaturers.
Keycap Widths (and Shapes)
Different keys have different widths. For example, on a common keyboard you will find that the control key is much wider than a key for a letter or number. Very commonly you will find people having to refer to what "Width" (or "Length" if it's a numberpad Enter key) they are. Taking the normal alpha key to be "1x" or "1 unit", we can describe all the other keys relative to this. A number followed by the 'x' represents what multiple of the basic 1 unit key that keycap is. For example: the control keys on most keyboards is 1.25x, i.e the control key is 1.25 times the width of the single unit key.
The following widths of common keys on keyboards:
Left Shift 2.25x
Right Shift 2.75x
Left Shift 1.25x
You may of noticed that I have left out the bottom row of keys (Control,Alt,Etc). That is because they're are two very common layouts for this. There is the "WinKey" layout, which is more modern and commonly found in newer keyboards. And there is a "WinKeyless" Layout, which can be found on older boards and still on some new boards. WinKeyless boards may also have their windows keys removed.
Typically in a WinKey layout, all the keys are 1.25x width and the spacebar is 6.25x. And as for the WinKeyless version, Ctrl and Alt are 1.5x, the "windows" key is 1x and the spacebar is 7x wide.
There other layouts out there but these ones encompass most of them.
Last part of this section is the shape of keys. Most keys are rectangular and can be described by their widths. But in some cases there may be different shapes. This is most likely going to be the case of the ISO "J-Return" or the "L-Return". The letters in the name are the shapes of the keys. The J return has the shape of a 1.5x key on top of a 1.25x key and the L return is a 1.5x attached to the 2.25x Return key.