Electrical switches play an important role in the function of many electrical devices. In the most basic sense, they allow for the flow or interruption of electrons in circuit. Switches are classified as a binary device, meaning they can operate either closed or open, depending on the setting. When the switch is open, the circuit is incomplete; thus, the electrons can no longer flow through it. In comparison, a closed switch allows electrons to flow through it without interruption.
But there are several different types of switches, each of which has a unique purpose. One of the most popular and widely used types of electrical switches is a membrane switch. So, what exactly is a membrane switch and how does it work?
A membrane switch operates much like a traditional electrical switch, allowing for the flow or interruption of electrons in a circuit. What makes the membrane switch different, however, is its use of a flexible substrate. ATSM International defines membrane switches as being “a momentary switch device in which at least one contact is on, or made of, a flexible substrate.” That sums up the term nicely, as membrane switches can open or close the circuit on an electrical device, featuring at least one contact that’s made of a flexible substrate.
While different companies use different construction practices when designing their membrane switches, most membrane switches feature a PET or ITO circuit, with the ink being copper, silver or graphite. Metals such as these are conductive, allowing for the flow of electrons.
Also, most membrane switches consist of four or more layers. This includes a top layer on which the graphic interface rests between the user and the machine, along with a printed circuit layer that’s made to create a flex circuit, usually made of copper and polyimide. During its construction, pressure-sensitive glues and adhesives are used to hold the components together.
There are several notable benefits associated with membrane switches, one of which is durability. Membrane switches are characterized by the use of a flexible substrate. This substrate normally acts as a barrier between moisture, dirt and debris, and the underlying electrical components of the respective device. In addition to being water and dirt-proof, membrane switches also offer a low profile. This makes them particularly useful in small devices where space is limited.
Hopefully, this will give you a better understanding of membrane switches and how they are used.