What Is a Membrane Switch?

Dec 30, 2020

Membrane switches are used in countless commercial and consumer electrical devices. Like all switches, they are designed to control a circuit. Membrane switches can open or close a circuit. When compared to other switches, though, membrane switches feature an entirely unique and different construction. What is a membrane switch exactly?

Overview of Membrane Switches

A membrane switch is a type of thin, multi-layered switching solution that’s constructed of an elastic and flexible material. According to ASTM International, membrane switches are designed with at least one of their contacts on a flexible substrate.

Most membrane switches have two contacts. A contact is a conductive trace or pill that’s used to control a circuit. When you press a button on a switch, the top contact will push into the bottom contact, thereby completing the circuit. When the two contacts pull away from each other, the circuit will revert back to its open and incomplete position. Membrane switches are defined by their use of an elastic and flexible material for at least one of these contacts.

How Membrane Switches Work

Most membrane switches are comprised of multiple layers. On top is a graphic layer consisting of legends and icons for the buttons. Below this layer is a space layer consisting of air or inert gas. There’s also a printed circuit layer featuring the switch’s circuitry. The layers are pressed together to achieve a slim and compact design that consumes a minimal amount of space.

Regardless of how many layers they feature, membrane switches rely on contacts to control a circuit. As previously mentioned, most membrane switches have two contacts per circuit. When the contacts are separated, the circuit will be open. Pressing the button will force the two contacts to touch each other. With electricity flowing through both of the contacts, the circuit will be closed — and the printed circuit layer will process this information.

Benefits of Membrane Switches

Membrane switches have become popular because of their small size. They are thinner and smaller than most other switching solutions. As a result, membrane switches can be used in small, handheld devices.

In addition to being small, membrane switches offer a high level of protection against moisture and liquids. They are made of multiple layers, with the uppermost layer sealing the switch’s underlying layers. This sealed design prevents moisture and liquids from reaching the printed circuit layer.

With their sealed design, membrane switches are also easy to clean. You can clean the buttons using a traditional cleaning production without fear of damaging the printed circuit layer or other components.

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