A touch switch is a special type of electrical switch that’s activated through physical contact, usually with the human operator. They are used in a wide variety of applications, ranging from computer terminals and smartphones to elevators and human machine interfaces (HMIs). Touch switches are classified as one of the most basic forms of tactile sensors, which is one of the reasons why their are so popular.
But there are several different types of touch switches, each of which has a different purpose. To learn more about the different types of touch switches and how they work, keep reading.
Capacitance switches are unique in the sense that they only need a single electrode to function. Normally, this electrode is placed behind a non-conductive material like wood, glass or even plastic. Capacitance switches work by using the electrical charge produced by the human operator. The switch charges and discharges to detect capacitance changes. So when a human operator touches it, the capacitance increases; thus, the switch identifies the operator’s input. Capacitance switches can also be used as a short-range proximity sensor.
Resistance Touch Switches
A second type of touch switch is a resistance touch switch. Unlike capacitance switches, this switch does not identify input through electrical charge. Rather, it works by placing two electrodes in contact with one another. This lowers the resistance between two pieces of metal; thus, allowing the resistance touch switch to function. Resistance touch switches are less common than capacitance, although they are still widely used in many industrial and commercial applications.
Piezo Touch Switch
A third type of touch switch is the Piezo touch switch. They are designed based on the principles of piezo ceramics, usually constructed behind a flat surface. Piezo touch switches support interfaces with virtually any kind of material. They can even function as an actuator, which is something that cannot be said for capacitance or resistance touch switches.
So, which type of touch switch works best? There are both pros and cons associated with each type. While a capacitance touch switch may work best in one application, perhaps a resistance touch switch will work best in another application. The bottom line is that you need to think about when and how you’ll be using the touch switch, and using this information, choose the most appropriate touch switch for the job.