A tact switch ;is a type of switch that is used every day but hardly ever seen. Hidden under every key of a computer keyboard, the tactile switch is small and thin, but features high reliability to ensure it will operate for years or even decades.
Tactile switches are small electromechanical devices that are designed to be mounted onto a printed circuit board (PCB). These products are compact with a low profile, meaning these do not rise high above the PCB, a vital attribute when considering the keyboards use for slim devices such as notebook computers.
Considering that space inside a keyboard is limited, the slim design means that tactile switches must compete with batteries, screens, and other components. To solve this, tactile switches are designed to be positioned side-by-side in a compact array, an attribute important for a keyboard.
The improvements made to the performance of smartphones and tablet computers make them a viable alternative to traditional computers. Tactile switches are small and convenient, suitable for touchscreens that utilize capacitive technology, which harnesses the electrical properties of the human body to function. For example, when a finger touches the screen, a tiny electrical charge is drawn to the point of contact, and the screen becomes a functioning capacitor. This in turn is detected as a push of a button.
Touchscreens are very thin, especially as there are no mechanical moving parts, and the technology is constantly improving to make them thinner still. With the constant improvement of touchscreens, why are manufacturers not making computer keyboards using capacitive technology? The answer to that question is the feel of keyboard keys, sometimes described using the word haptics.