A membrane touch switch is a type of electrical switch that’s activated through touch and features at least one flexible substrate. Like other electrical switches, they are used to activate and deactivate circuits. Membrane touch switches are considered to be momentary because they return back to their original, default state when the user’s finger is removed from the touch sensor. To learn more about membrane touch switches and how they work, keep reading.
While different membrane touch switches are designed in different ways, most follow a similar construction: they feature an open connection with space separating two electrical contacts. Upon pressing the button or sensor, however, the two contacts touch each other; thus, closing the circuit and activating the device. Removing your finger from the button or sensor allows the circuit to revert back to its open position, as the device is deactivated. It’s a relatively simple concept that’s used in a wide range of touch-controlled devices, including lamps, calculators, displays and more.
Normally, a membrane touch switch features a few basic component, including a top layer, graphic, circuit layer, spacer layer, underlying circuit layer, backing and support layer. Of course, different materials are used to create these layers, with some switches requiring the use of a specific type of material (e.g. conductive material).
There are actually three different types of membrane touch switch, including the following:
- Capacitance: like capacitive smartphones, capacitance switches use the body’s capacitance to identify touch and open/close the circuit. They require only one electrode to operate, which is typically found behind a panel made of non-conductive material like glass or plastic.
- Resistance: this type of membrane touch switch features two electrodes, both of which need to be in contact with a finger or other electrically conductive material to work. Touching the switch creates an open or closed state. Resistance switches feature a more simplistic design than their capacitance counterpart.
- Piezo: perhaps the least common type of membrane touch switch, piezo switches live up to their namesake by using the piezo ceramic bending properties. They are constructed behind a panel or surface, allowing the switch to work with a wide variety of materials. Piezo touch switches are unique in the sense that they can be used as an actuator.
Additionally, you’ll find that membrane touch switches are either tactile or non-tactile. Tactile switches produce some type of feedback when activated, whereas non-tactile switches do not. Many users prefer tactile touch switches because it improves accuracy while reducing errors.