How touch desk lamps work
1. Traditional touch dimming, touch switches have been very mature, mainly for table lamps and corridor lights.
2. The principle is roughly when the finger touches the metal electrode, the 50Hz AC near the human body induction acts as a clutter trigger control circuit, or the human body's resistance to ground changes the internal RC oscillation frequency and phase.
3. In general, when a finger is touched, a bare metal sheet is required to be touched by a finger. Most of the internal circuits of this type of circuit are powered by a non-isolated power supply, and the direct touch always gives a feeling of insecurity. Some touch films have a thin layer of insulating paint, but it's also not much of an old problem: touch with gloves doesn't work.
4. There is now a new generation of capacitive touch sensing technology that detects the touch action by detecting slight changes in capacitance between the metal electrode and the finger when the finger is approaching. It can function across the insulating panel and can penetrate several millimeters thick. Plastic, glass and other insulating materials.
5. Capacitive touch buttons using this technology have appeared in induction cookers, microwave ovens and mobile phones. If the insulator is separated by a few millimeters between the electrode and the finger, the equivalent capacitance should be very small. The principle of technology implementation is very different from that of a traditional touch key. With this capacitive touch sensing technology, you can make fully insulated touch dimmer lights, touch switches, sensing electrodes installed in the back of the insulating housing or panel, fingers only touch on the panel, it should be absolutely safe!