Description

Touch switches and tactile switches operate by touching or pressing to make a connection. Touch switches are touch-operated devices that do not have moving parts. Tactile switches are electromechanical and provide tactile feedback.

Specifications

Specifications to consider when searching for touch switches and tactile switches include maximum current and maximum power, shock and vibration ratings, and compliance with Ingress Protection (IP) standards.

Operation

Touch switches operate by human touch, as opposed to making or breaking a mechanical connection by pushing a button or flipping a switch. Many different principles can be used to operate a touch switches. Examples include:

• Temperature
• Resistance
• Radio reception
• Acoustic resonance dampening
• Capacitance

Typically, touch switches and do not provide any tactile feedback.

Tactile switches are so named because they provide tactile feedback to the user when the button or switch has made contact with the control panel beneath, usually a printed circuit board (PCB).

Applications

Tactile switches are electromechanical switches designed for keyboard, keypad, instruments or interface control-panel applications. They are used extensively in aerospace and aviation, defense, communication and all electronic instrumentation applications. Specialized touch switches and tactile switches are also available.

Types

Selecting touch switches and tactile switches requires an understanding of switch types. Choices include tact switches and keyswitches.

Tact switches are tactile electromechanical switches for keyboards, keypads, instruments or interface control-panel applications. Keyswitches are tactile mechanical switches that are designed for keyboards and keypads. Both types of tactile switches give the user sensor or tactile feedback that the button or switch has made contact with the control panel beneath, usually a printed circuit board (PCB). 

Touch switches and tactile switches also include dome switches, tactile switches that are so named for their location under a rubber bubble or dome. When a dome switch is pressed, it collapses the dome and makes the switch contact. Dome switches are used in keywords and membrane keypads. They are relatively quiet when operated, and are a good choice for office and consumer environments. Tactile metal domes and metal dome arrays are also commonly available. 

Accessories

Accessories for touch switches and tactile switches such as dome switches include dome placement pens and automated dome placement systems. A dome placement pen is a handheld device for the manual placement of a metal dome. An automated dome placement system can be used to place large numbers of tactile metal domes on PCBs, membranes, or flex circuits.

Other accessories for touch switches and tactile switches are also available.

Standards

EIA-498B000 - This Sectional Specification covers a limited range of touch stroke tactile feel switch panels, the bases for which are etched type printed circuit boards.

ASTM F1997 - This test method establishes procedures for depressing and releasing a tactile membrane switch to determine the amount of switch teasing, if any.

References

Image Credits:

Panasonic | Digi-Key Corporation | C&K Components