Keyboards
A keyboard is a device that sends signals to a computer. A keyboard is mainly used to enter text, but the OS can also be operated using special keys. The typical design of a keyboard is a long rectangular shape with keys positioned on top. The keys are assigned with numbers, letters or symbols on their surface. The number of keys varies according to the standard, but the three main types are the 101-key keyboard, 106-key keyboard and 109-key keyboard. Various keyboard structure types are also available. For example, in a mechanical keyboard, a switch and spring are used on the inner side of the keys. A membrane keyboard is made from an insulated sheet sandwiched between two conductive sheets. In an isolation keyboard, there is larger space between the keys.