Electrical switches are used in countless applications to control an electrical circuit. When a switch is pressed, the circuit closes. When a switch is released, the circuit reverts back to its default open position. While all electrical switches rely on this method of operation, some are designed to open or close the respective circuit open touch. Known as a touch switch, the two most common types include capacitive and resistive. So, what’s the difference between capacitive and resistive switch switches?
What Is a Capacitive Touch Switch?
A capacitive touch switch is a touch-controlled electrical switch that requires the use of a single electrode. Like capacitive touchscreen devices, it uses the human body’s capacitance to identify commands. When you press your finger against a capacitive touch switch — even while using little or no force — your finger will absorb some of its electrical current, which is produced by an electrode. As a result, the capacitance of your body will increase, whereas the capacitance of the touch switch will decrease. The switch is able to recognize this nuance to identify your touch.
What Is a Resistance Touch Switch?
Resistance touch switches are also designed to open or close an electrical circuit using touch. Unlike capacitive touch switches, however, resistance touch switches require the use of two electrodes. Both the electrodes must be in direct contact with an electrically conductive object or surface in order for the switch to register a command. Upon tapping or touching a resistance touch switch, the resistance between the two electrodes decreases, thus allowing the switch to register your command. And when you release your finger from the resistance touch switch, resistance between the electrodes increases back to its normal state.
Other Types of Touch Switches
While capacitive and resistance are the two most common types of touch switches, there are other types available on the market. Piezo, for example has become a popular alternative to capacitive and resistance touch switches. They are called “piezo” because they use the properties of piezo ceramic to open and close an electrical circuit.
What’s great about piezo touch switches is that they work with any object, regardless of whether the object is conductive or nonconductive. You can’t just tap a capacitive or resistance touch switch with a plastic pen, for example. Because plastic is nonconductive, it won’t register as a touch command. Piezo touch switches solve this problem by supporting both conductive and nonconductive objects.