Electrical switches are designed to create an open or closed electrical circuit via user controls. When a user presses his or her finger on a switch, the switch deforms to create a closed circuit. When the user releases his or her finger, the circuit opens. This otherwise simple process is used to power a variety of devices, including computers, remote controls, lamps, smart appliances and more. There are different types of switches, however, including touch switches and membrane switches. Although they work in a similar manner, touch switches and membrane switches have their own unique characteristics.
Overview of Membrane Switches
A membrane switch is a special type of electrical switch that contains one or more contacts made of a flexible substrate. They typically feature four layers. The top layer is a graphic interface on which logos and buttons are printed. Beneath it is a printed circuit, typically made of conductive material like PET or ITO. Because of their flexible qualities, membrane switches are ideal for use in small devices. Furthermore, they support a variety of backlighting options, including light-emitting diode (LED), electroluminescent (EL) and optical fiber.
Overview of Touch Switches
A touch switch performs the same basic operation as a membrane switch — and all other switches — by creating an open or closed electrical circuit. The way in which it accomplishes this, however, differs from its membrane counterpart. Touch switches live up to their namesake by supporting touch-based controls. In fact, touch switches are even used in touchscreen devices specifically for this reason.
The 3 Types of Touch Switches
There are three specific types of touch switches, including capacitive, resistive and piezo. Capacitive touch switches, the most common type, feature an electrode behind a panel. They work on the principle of capacitance by measuring changes in capacitance. When you press your finger on a capacitive touch switch, it causes the switche’s capacitance to change. The switch is able to identify this change in capacitance, which it uses to determine when the switch was touched.
Resistive touch switches work on the principle of pressure. Pressing down on a resistive touch switch causes an upper and bottom layer to make contact, so it’s able to identify the user’s touch. Piezo touch switches work on the principle of piezo ceramic. They aren’t used as frequently as capacitive or resistive touch switches, but they are the only type of touch switch that can operate as an actuator as well.