When researching capacitance touchscreens — the most common type of touchscreen technology — you may come across finger capacitance. Whether it’s a projected capacitance or surface capacitance touchscreen, all capacitance touchscreens use finger capacitance to detect touch commands. It’s an underlying mechanism that drives their performance. What is a finger capacitance exactly, and why do capacitance touchscreens use it?

Overview of Finger Capacitance

Finger capacitance is the colloquial term used to describe the electrical charge added to a capacitance touchscreen’s surface in respond to a touch command. When you place your finger on the surface of a capacitance touchscreen, it will absorb some of your body’s electrical charge. It’s not a substantial amount of electricity. Rather, it’s a small electrical charge that only the capacitance touchscreen will notice. Nonetheless, this added electrical charge is known as finger capacitance because it origins from your finger.

How Finger Capacitance Works

To understand how finger capacitance works, you must familiarize yourself with the basic properties of capacitance touchscreens. Capacitance touchscreens are devices that detect touch commands by measuring capacitance. When turned on, they’ll project a uniform electrostatic field across the display interface. Capacitance touchscreens will then measure this electrostatic field.

Since the human body has electrically conductive properties, touching a capacitance touchscreen with your bare finger will change its electrostatic field. Your finger will essentially add a small electrical charge to the device’s display interface. As a result, the capacitance touchscreen’s electrostatic field will increase in the area of your touch command. Finger capacitance is simply the extra electrical charge that’s added to the display interface from your finger.

Finger Capacitance: What You Should Know

Although it’s called “finger capacitance,” this electrical phenomenon isn’t restricted to your finger. You can use any conductive object to control a capacitance touchscreen. As long as an object conducts electricity, it will distort the device’s electrostatic field.

A common example is a conductive stylus. Conductive styluses look like all other styluses. The only difference is that they are made of a conductive material. When you touch a capacitance touchscreen’s display interface with a conductive stylus, it will add finger capacitance to it. Therefore, the device will respond by recognizing and registering your touch command in that area.

In Conclusion

Finger capacitance is an electrical charge that’s added to a capacitance touchscreen from a finger or conductive object. It allows capacitance touchscreens to detect touch commands. When finger capacitance is added, the device will recognize it as a touch command.