This microscopic scale and sensitivity allows the sensor to map a high-resolution image of electrical charge that occurs over the surface of a source material (for example a human finger), when it makes contact with a thin insulating surface (ie a plastic surface).
FedEx equips package sorters with scanners built into a ring on their finger, which communicate wirelessly with a computer on their waist, itself in contact with a central computer, keeping tracking information up-to-the-minute accurate.
As Elgar's Nimrod was played by the military band and wreathes were being laid, I felt a finger lifting the headphones off my ears and heard my radio engineer whisper that I was to contact the newsroom urgently.