Switches are found in nearly all electrical devices. They are simple components that control a circuit. When closed, electricity will travel through the switch, thereby completing the circuit. When open, the flow of electricity will be interrupted, thereby breaking the circuit. While some switches use a mechanical method of operation to control a circuit, however, capacitive switches use a touch-based method of operation.
A Brief Introduction to Capacitive Switches
What are capacitive switches exactly? They are touch switches that open or close a circuit — or multiple circuits for that matter — by measuring changes in capacitance. All switches, of course, can open or close a circuit. The difference is that mechanical switches have moving parts, whereas capacitive switches do not.
As a type of touch switch, capacitive switches don’t have any moving parts. They rely entirely on capacitance to control a circuit. Touching the button on a capacitive switch with a bare finger will allow it to change the orientation of the circuit.
How Capacitive Switches Work
They may sound complex, but capacitive switches use a relatively simple method of operation. As previously mentioned, they don’t have any moving parts. Capacitive switches and other types of touch switches respond to physical contact. Capacitive switches will change the orientation of their circuit when exposed to a conductive object, such as a bare finger.
During use, capacitance switches will apply an electrical charge to their interface. They will measure this electrical charge while looking for changes in capacitance. If you touch the button with a bare finger, you’ll change the capacitance. Your finger will absorb some of its electrical charge. The capacitive switch will notice this change in capacitance, and it will respond by opening or closing the circuit.
Some of the benefits of capacitive switches include the following:
- Durable and long-lasting
- Easy to use (doesn’t require pressure)
- No risk of mechanical failure
- Weather resistant
- Available with or without backlighting
- Supports embossing
Capacitive Switch Construction: What You Should Know
There are many different types of capacitive switches, but they typically feature three parts: a graphic overlay, circuit and backer. The graphic overlay is the top layer. It features the buttons and icons that you can touch to control the circuit. The circuit is found directly below the overlay. It features the conductive pathways that either allow or interrupt the flow of electricity. Finally, the backer features the adhesive used to bond the housing or substrate.