Membrane Switch

A membrane switch is an electrical switch for turning a circuit on and off. It differs from a mechanical switch, which is usually made of copper and plastic parts: a membrane switch is a circuit printed on PET or PC The ink used for screen printing is usually silver / graphite filled and therefore conductive.
We defines a membrane switch as "a momentary switch device in which at least one contact is on, or made of, a flexible substrate."
A membrane switch typically has 4 or more layers. The top layer of a membrane switch is the graphic interface between the user and the machine. The other critical layer is a printed circuit. This can also be a flex circuit made of copper and PE material. The layers are normally assembled using pressure sensitive adhesives although inexpensive designs can be held together through other mechanical means such as a keyboard housing. Contact between two traces can be made through a printed shorting pad or through a metal dome that stands on legs.
Classic applications includes microwave oven panel, air conditioner control panel, TV remote control, Medical Equipment, Industrial instrument, electronic meter etc. Tactile feedback of keys can be provided by embossing the top PET layer or embedding metal snap domes, polyester domes or forming the graphic layer. Membrane Switches are connected to circuit boards by standard pin connectors or via a ZIF or LIF connector. Benefits of membrane switches can include ease of cleaning, sealing ability and their low profile.