eli5: How does a smart phone know you are touching the screen with more than one finger, or doing a gesture?

Question

eli5: How does a smart phone know you are touching the screen with more than one finger, or doing a gesture?

In: Technology

Answer 1

Sense and transfer human electricity.

In the capacitive system, a layer of an electroconductive material (most often indium tin-oxide) that stores an electrical charge is placed on the glass panel of the monitor. When a user touches the monitor with his finger, some of the charge is transferred to the user, so the charge on the capacitive layer decreases.