There are two main keyboard technologies: mechanical or switch, and non-mechanical or capacitive. Each technology has its own specific design and usefulness.
Mechanical Keyboards – Each key on keyboard is attached to a key switch which on being pressed makes a circuit, giving a signal. This electronic signal is converted to a digital code usually ASCII by the keyboard’s controller, and sent to PC. It can be repaired, is expensive and makes ‘tik-tik’ noise when typing
Non-Mechanical Keyboards – It uses a key switch housing having conductive plates and a stem. When a key is pressed, the stem pushes the top plate toward the bottom plate, causing a change in capacitance which is noted by the keyboard controller and sent to PC after conversion to digital code. It is not repaired due to low cost and is cheap as compared to mechanical keyboards.