Membrane Switches

A membrane switch is an electrical switch that is used for turning electrical circuits on and off. This type of switch is different from a mechanical switch, which is usually made of copper and plastic parts. A membrane switch is a circuit printed on a PET or ITO. When you press those aesthetic, small buttons on your microwave oven and washing machine, you have just used a membrane switch.

The switches are used to enter data or to select values. You can operate menu driven software with them and give various types of commands through them. They come in graphical and numerical keypads, switch overlays and control panels, etc. Membrane switches can be designed to give a very good look and feel with graphics and illumination. Graphics may conform to international standards or they may be customized to the application. Typical graphics include arrows, pictorials of machine operations or processes, etc. Control panels include full function panels for monitoring and control of machine, process, or system variables and commands. Membrane switch overlays are graphical or alphanumeric coverings for keypads indicating key or switch functions.

Membrane switches are used extensively in items such as ATMs, calculators, game consoles, remote controls, domestic appliances, self-help info systems, testing and measurement devices, etc. Membrane switches are made of up of five individual layers which are known as: graphic, membrane, tactile, static, and rigid layers. The bottom layer is connected to the PCB of the device. Membrane switch types can be tactile or non-tactile, flat, raised, domed, etc. The material used to make them can be ITO, PCB, polyester, polyimide, polycarbonate, metal, rubber and silicone.

Most membrane switches come with special features such as illumination, LED indicators, outdoor environment, hazardous environment, vandal proof, washdown capable, EMI / RFI protection, ESD protection, and embossed switches.

Membrane switches are used in many different industries such as aerospace, automotive, building controls, communications and electronics, financial services, manufacturing and automation, medical, retail, and security and identification. While ordering membrane switches, you need to mention: the graphics to be used, the actuation force, contact bounce, termination, length of key travel, the rated voltage/current and the embossing needed. Membrane switches normally last for more than a million cycles in a dust-free environment, but they can be damaged if they are handled roughly.

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