A touch-sensitive lamp is one that is activated by human touch rather than a flip, pushbutton, or other mechanical switch. These lamps are popular as desk and nightstandlamps. They act on the principle of body capacitance. Nowadays the USB powered touch-sensitive lamp is popular in using with the computer. The touch-sensitive is not only an ON/Off switch but also a dimmer switch, that allows one to make an electric light brighter or less bright.
Video demonstrating the operation of a touch-sensitive lamp