How do touch lamps work?

Question

i know you touch them and they just turn on, but how does it only turn on with the touch of your skin and not anything else? its been on my mind for like twenty minutes and i can't figure it out!

Answer 1

it's work on belong to body temperature

Answer 2

a extremely high gain device is used to control a solid state switch.

your body generates voltage, a high impedance, high gain device sees that voltage change and causes a solid state switch to change condition.

touch lamps are horrid RF polluters and should be fed to landfills.