In look and feel, the mechanical keyboard resembles the traditional typewriter keyboard. There is a familiar click as you depress a key and a positive tactile sensation as you use it. A positive tension is produced by a coil spring hidden inside each key, and each key rests on a plunger. As your finger presses down, a contact is closed, completing the circuit and sending a signal. Mechanical keyboards are a bit more complicated to manufacture than some other forms because of the number of parts involved.
Membrane switches, on the other hand, have a very small number of parts.
This type of keyboard has a membrane located underneath the keys. When a key is touched, pressure is exerted against the membrane, closing the switch. Cheap membrane keyboards have an inferior touch to them and are not suitable for heavy use. The standard keyboard for systems today is based on the enhanced 101-key design developed by IBM in conjunction with the release of the IBM AT in 1986. There are a few variations from the 101 keyboard being sold, but they are variations of the 101 standard, not departures.