Technology
How does a touchscreen work?
Most modern touchscreens work by sensing your finger's electrical charge. The screen holds a grid of transparent electrodes carrying a tiny charge; your fingertip distorts that field at the point of contact, and the device calculates exactly where you touched.
See it in motion.
Watch a 2-minute animated lesson that shows exactly how a touchscreen works.
Step by step
- 1Capacitive screens coat the glass with a transparent conductor holding a small electric charge.
- 2Your skin is slightly conductive, so touching the screen changes the local charge (capacitance).
- 3Sensors detect where the field changed and a chip computes the coordinates.
- 4It can track several points at once, enabling pinch-to-zoom and multi-finger gestures.
- 5Older 'resistive' screens instead sense physical pressure pressing two layers together.
Frequently asked questions
- Why don't touchscreens work with gloves?
- Most gloves block your finger's tiny charge from reaching the screen, so the capacitive sensor detects nothing — unless the gloves have conductive tips.
- What's the difference between capacitive and resistive screens?
- Capacitive screens sense your finger's charge and allow multi-touch; resistive screens sense pressure, work with any object, but read only one point at a time.
- Why does a wet screen misbehave?
- Water is conductive, so droplets create false touches by changing the field just like a finger would.