• Question: How do touch screens work?

    Asked by dong to Mike, Pip, Tianfu, Tim, Tom on 29 Jun 2012.
    • Photo: Tom Lister

      Tom Lister answered on 29 Jun 2012:

      Most work by having two (transparent) plates which come into contact when you touch them, effectively working like lots of buttons. There are other ways of triggering these buttons, such as by using the capacitance of your finger (these ones don’t work if you use a pen on them).

    • Photo: Tim Stephens

      Tim Stephens answered on 29 Jun 2012:

      The two transparent plates type of touchscreen use an electronic circuit that measures the resistance between the plates. When you touch the screen the resistance changes and depending on what the resistance is, the circuit knows where you touched.
      The other type that Tom mentions is the capacitive touch screen (like on iPhones and Androids) that use an electronic circuit that detects changes in the capacitance of the screen when your finger touches it. Again, depending on how the capacitance changes, the circuit knows where you touched the screen.

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