Capacitive switches are often preferred over traditional switches because of their responsiveness. Like capacitive touchscreen devices, they rely on the body’s capacitance. When you touch a capacitance switch, your body will absorb some of its electrostatic field, allowing the switch to register your command. But if you’re planning on purchasing a capacitive switch for your business, there are several things you need to consider.
#1) Circuit Board
All capacitive switches are designed with a circuit board that sits between the graphic overlay and backer layer. When choosing a capacitive switch, check to see what type of circuit board it uses. The two most common types are Printed Circuit Boards (PCBs) and Flexible Printed Circuits (FPCs), the latter of which features a flexible construction that can bend without breaking.
#2) Overlay Material
You should also consider the type of overlay material used in the capacitive switch’s construction. Different capacitive switches are designed with different overlay layers. Some feature an overlay layer made of plastic, for example, while others use acrylic or glass for the overlay layer. The overlay layer material must be non conductive so that it doesn’t interfere with the capacitive switch’s ability to register user commands.
It’s not uncommon for capacitive switches to feature a backlight. A backlight is a component that’s responsible for illuminating the capacitive switch and its respective buttons. The most common types of backlighting used in capacitive switches is light guides and light-emitting diode (LED), both of which offer thousands of hours of usage while consuming minimal energy in the process. There are also fiber optics and electroluminescent (EL) backlighting solutions available. Check to see what type of backlighting, if any, a capacitive switch features before purchasing it.
Finally, you’ll probably want to include graphics on your capacitive switch — and that’s okay. The overlay layer supports custom colors, icons and graphics, allowing for an unlimited level of customization and versatility. If you’re going to use the capacitive switch on a human machine interface (HMI), you should customize it with the appropriate graphics so that workers will know how to control it with the HMI.
These are just a few things to consider when choosing a capacitive switch. It’s important to note that there are other types of electrical switches. Piezo switches, for example, rely on the piecoelectric effect to register user commands. It’s a highly effective alternative to capacitive switches. But if you’re going to purchase a capacitive switch, pay attention to the four things described here.