system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: how do touch lamps work?
gpt
Most touch lamps have a small computer circuit in them that is measuring and sensing the capacitance of the metal frame of the lamp.

Capacitance is the ratio of the amount of electrical charge stored in a conductor like the metal lamp frame compared to that conductors electrical potential. (how much charge could be stored)

By your touching the lamp - you change its capacitance which the computer reads as “someone touched me” and changes the brightness using a dimmer circuit which limits the lights brightness or turns it off completely on a more basic lamp.


TL:DR

They replaced the pull chain or switch that turns a light on and off - with a computer that’s waiting for an input. The input is your skin changing the electrical properties of the frame of the lamp.