Capacitive

iPhones have capacitive touchscreens.

A simple plastic stylus won't work on a smartphone's capacitive touchscreen. You need a capacitive or active stylus instead.

Capacitive touchscreens are all glass and designed for use in ATMs and similar kiosk-type applications.

A line voltage detector unit ascertains where the supply is 25 kV. or 6.25 kV. and appropriate connections of the transformer primary winding are made through voltage-sensitive relays fed from a capacitive potential divider.