Question: How do touch screens work?

Rob Temperton answered on 16 Jun 2015:

There are two types of touch screen that I know of – resistive and capacitive. Resistive are the old type and capacitive are the nice ones that you find on smartphones and tablets.

Resistive touch screens work by having a conductive flexible membrane and a conductive film. You push on the membrane and make contact with the film. Using electronics (measure the resistance from the edges of the screen to the contact point in the x and y directions) you can therefore work out where you make contact between the two films.

Capacitive screens are a bit more responsive – you don’t need to press hard onto a membrane. It works in a similar way, but rather than a change in resistance, when you bring your finder near the screen , a change in capacitance is measured. Again, by measuring this from multiple places, the x and y position can be calculated.

Rob