How do keyboards work

It's up to you which version you prefer. Finally, one more consideration is how noisy the switches are. Switches generally make an audible click when they are pressed, which is louder than a rubber dome keyboard.

But some mechanical switches are louder than others, so you should consider whether the noise will bother you or the people around you. The best-known manufacturer of mechanical switches is Cherry. This company is well-known for their high quality switches. On most high-end mechanical keyboards , you'll find they are advertised as coming with "Cherry MX" switches.

Within the category of Cherry MX switches, there are a number of different styles available. These switches have different characteristics and are known by color names. Some of the Cherry MX switches you'll come across are:. It used to be the case that if you wanted a high-quality mechanical keyboard, you had to go with Cherry switches. But that's not the case any more. Several other companies make their own switches, which can be of comparable quality and can be used in more affordable mechanical keyboards.

Some of these are Cherry clones, meaning they are other brands' interpretations of the Cherry versions. Others are original switch designs which have slightly different feels and characteristics. The best way to decide what kind of switches you want for your keyboard is to try out as many as you can. Try out a friend's keyboard, or go to a computer store and try their sample keyboards. If this isn't possible for you, then Cherry MX Brown switches are the option which is likely to be most pleasing for most people and use cases.

Mechanical keyboards are more expensive than regular keyboards. And you need to try out a variety of switches to find the one that suits you. But if you type or game a lot, then the greater accuracy and ease of use can make a mechanical keyboard a worthwhile investment.

Can't find the exact perfect keyboard for your needs and feeling adventurous? A character map is basically a comparison chart or lookup table. It tells the processor the position of each key in the matrix and what each keystroke or combination of keystrokes represents. For example, the character map lets the processor know that pressing the a key by itself corresponds to a small letter "a," but the Shift and a keys pressed together correspond to a capital "A.

A computer can also use separate character maps, overriding the one found in the keyboard. This can be useful if a person is typing in a language that uses letters that don't have English equivalents on a keyboard with English letters. People can also set their computers to interpret their keystrokes as though they were typing on a Dvorak keyboard even though their actual keys are arranged in a QWERTY layout.

In addition, operating systems and applications have keyboard accessibility settings that let people change their keyboard's behavior to adapt to disabilities. Sign up for our Newsletter! Mobile Newsletter banner close. This is known as typematics. In this process, the delay between each instance of a character can normally be set in software, typically ranging from 30 characters per second cps to as few as two cps. Keyboard Technologies Keyboards use a variety of switch technologies.

It is interesting to note that we generally like to have some audible and tactile response to our typing on a keyboard. We want to hear the keys "click" as we type, and we want the keys to feel firm and spring back quickly as we press them.

Let's take a look at these different technologies:. This keyboard uses rubber dome switches. Probably the most popular switch technology in use today is rubber dome. In these keyboards, each key sits over a small, flexible rubber dome with a hard carbon center.

When the key is pressed, a plunger on the bottom of the key pushes down against the dome. This causes the carbon center to push down also, until it presses against a hard flat surface beneath the key matrix. As long as the key is held, the carbon center completes the circuit for that portion of the matrix. When the key is released, the rubber dome springs back to its original shape, forcing the key back up to its at-rest position. Rubber dome switch keyboards are inexpensive, have pretty good tactile response and are fairly resistant to spills and corrosion because of the rubber layer covering the key matrix.

Membrane switches are very similar in operation to rubber dome keyboards. A membrane keyboard does not have separate keys though. Instead, it has a single rubber sheet with bulges for each key. You have seen membrane switches on many devices designed for heavy industrial use or extreme conditions. Because they offer almost no tactile response and can be somewhat difficult to manipulate, these keyboards are seldom found on normal computer systems.

Capacitive switches are considered to be non-mechanical because they do not simply complete a circuit like the other keyboard technologies. Instead, current is constantly flowing through all parts of the key matrix. Each key is spring-loaded, and has a tiny plate attached to the bottom of the plunger.

When a key is pressed, this plate is brought very close to another plate just below it. As the two plates are brought closer together, it affects the amount of current flowing through the matrix at that point.

The processor detects the change and interprets it as a keypress for that location. Capacitive switch keyboards are expensive, but do not suffer from corrosion and have a longer life than any other keyboard. Also, they do not have problems with bounce since the two surfaces never come into actual contact. Metal contact and foam element keyboards are not as common as they used to be. Metal contact switches simply have a spring-loaded key with a strip of metal on the bottom of the plunger.

When the key is pressed, the metal strip connects the two parts of the circuit. The foam element switch is basically the same design but with a small piece of spongy foam between the bottom of the plunger and the metal strip, providing for a better tactile response. Both technologies have good tactile response, make satisfyingly audible "clicks" and are inexpensive to produce. The problem is that the contacts tend to wear out or corrode faster than on keyboards that use other technologies.

Also, there is no barrier that prevents dust or liquids from coming in direct contact with the circuitry of the key matrix. From the Keyboard to the Computer As you type, the processor in the keyboard is analyzing the key matrix and determining what characters to send to the computer. It maintains these characters in a buffer of memory that is usually about 16 bytes large. It then sends the data in a stream to the computer via some type of connection.

Normal DIN connectors are rarely used anymore.