Choosing Tactile Switches for Your Electronic Applications

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 harness 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 a computer keyboard using capacitive technology? The answer to that question is the feel of keyboard keys, sometimes described using the word haptics. Despite the capabilities of touchscreens, these are hard and unforgiving. While there are many advantages of this smooth, flat surface - these are easy to clean and provide an effective compliment for high definition displays - these provide no feedback to the user, showing why the tactile switch is so useful.

The tactile switch is a mechanical device. The force required to depress the switch, the distance it travels, and the spring as it returns once released all contribute to the “feel” of the switch. The most obvious example of how the haptics of a tactile switch affects the functioning of a device can be found in the computer keyboard discussed earlier. Anyone who uses a computer frequently will know that the movement of the keys on a keyboard can have a real impact on its ease of use, which in turn affects factors including typing speed and operator fatigue. It is the tactile switch that gives the keyboard its feel and familiar clicking noise when a key is depressed.

Offering a combination of low profile, high reliability, and mechanical feedback, tactile switches are suitable for use in many applications. The market for wearable technology is growing quickly, driven by the huge adoption of smartphones and the expansion of high-speed internet services.

Building sophisticated electronics into garments or devices that are designed to be worn requires components such as tactile switches that are not bulky or heavy, creating a design opportunity for wearable technology applications that require innovative visual indicators or control panels.

For example, a soldier wearing smart body armour in a tactical environment or a paramedic using body-mounted cameras might find it unwise to display unwanted light. In situations like these, tactile switches provide the user with both ease of use and a physical indication of correct operation.

Manufacturers tactile switches available for variety of uses, When combined with the huge array of keys and actuators that are available, the tactile represents one of the most versatile switches on the market today.

Why is Micro Switch called a micro switch

Micro switch is an electric switch (patented in 1932) that is actuated by very little physical force. Switching happens at specific positions of the actuator (not like other switches). Relatively small movement at the actuator button produces a relatively large movement at the electrical contacts, which occurs at high speed (regardless of the speed of actuation). Typical durability is from 1 to 10 millions of cycles. This durability is a natural consequence of the design.

Micro switches are not operated by person; it is always some moving part of the equipment. Common applications are detection (e.g. jammed paper in photocopier, the presence of material or product). Other application can be a limit switch (for control of machine tools) or door switch (e.g. fridge).