How do touch lamps work?

Touch-sensitive lights seem simple enough but their switches work on the principle of body capacitance.

Asked by: Richard Simpson, Hastings

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Touch lamps work on the principle of capacitance – the amount of charge something can soak up. In circuits, components called capacitors store varying amounts of charge and are used to tune circuits like radio receivers or smooth out fluctuations in voltage. When we make contact with a touch lamp, we alter its capacitance. The lamp detects this and switches on or off accordingly.


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