The working principle of touch switch for table lamp
Now there is a new generation of capacitive touch sensing technology, through the detection of finger is close to a small change in capacitance between the metal electrode and the fingers, to detect the touch action through the insulation panel function, can penetrate a few millimeters thick plastic, glass and insulating materials. Using this technology of capacitive touch buttons has appeared in the electromagnetic oven, microwave oven and mobile phone. A few mm between the electrode and the finger insulator, the equivalent capacitance value should be very small, technology principle and traditional touch keys are not the same.
The general requirements of sheet metal finger touch contact exposed, this kind of internal power supply circuit mostly used are not isolated, direct touch. Always give a person a kind of feel safe enough. Some touch with insulating paint a thin layer, but not much.
The traditional touch dimmer, touch switch has been very mature, is the main lamp and corridor lamp. The principle is roughly finger contact with metal electrodes, 50Hz alternating current induction of the human body near the clutter as a trigger control circuit, or the body of resistance to change the internal RC oscillation frequency and phase.
