Touchscreens aren’t the only devices that use capacitive technology. Many switches use this same type of touch-based technology. Known as capacitive switches, they open and close a circuit by measuring a uniform electrostatic field. If a capacitive switch detects a change in this electrostatic field, it will respond by opening or closing the circuit. This post reveals five common myths about capacitive switches.
#1) Contain Moving Parts
Capacitive switches don’t contain any moving parts. Switches that contain moving parts are mechanical switches. Capacitive switches aren’t mechanical switches because they don’t contain any moving parts. Instead, they are touch switches that use a touch-based method of operation to control a circuit.
Since they don’t contain moving parts, capacitive switches are long-lasting. They don’t suffer from the same degree of premature wear and tear as mechanical switches. You can use a capacitive switch for many years without fear of it failing prematurely.
#2) Requires Multiple Electrodes
Another common myth is that capacitive switches require multiple electrodes. The truth is that capacitive switches only need a single electrode. This electrode is typically placed behind the top layer. When exposed to a conductive object, such as a bare finger, it will open or close the circuit.
#3) Only Available With PCBs
All capacitive switches have a circuit. With that said, some of them feature different types of circuits than others. You can find capacitive switches with a Printed Circuit Board (PCB), and you can find them with a Flexible Printed Circuit (FPC). FPCs live up to their namesake by featuring a flexible substrate on which the circuit is printed.
#4) Doesn’t Support Backlighting
You can find capacitive switches with and without backlighting. Capacitive switches support backlighting. It’s an optional feature that’s used to improve the visibility of a capacitive switch in dark and other low-light environments. Backlighting options for capacitive switches include light-emitting diode (LED) and electroluminescent (EL). LED and EL backlighting may further be used with light guides. Light guides can make a capacitive switch more efficient while simultaneously protecting it from bright spots.
#5) Overlay Must Be Made of Glass
The overlay of a capacitive switch doesn’t have to necessarily be made of glass. Some capacitive switches do, in fact, have a glass overlay. Others, though, feature a different type of overlay. In addition to glass, the overlay may be made of plastic. Plastic is transparent and nonconductive, making it a suitable material for the overlay. You can also find capacitive switches with an acrylic overlay. Regardless, glass, plastic and acrylic are three of the most common materials in which capacitive switch overlays are made.