Classification of table lamp control methods

1. Touch-based
The principle of touch desk lamp is to install an electronic touch IC inside, and form a control loop with the electrode sheet at the touch of the desk lamp.
When the human body touches the sensing electrode, the touch signal is transmitted to the touch sensing end by pulsating direct current to generate a pulse signal, and then the touch sensing end will send a trigger pulse signal to control the light on; Touch again, the touch signal will be transmitted to the touch sensing end by pulsating direct current, at which time the touch sensing end will stop sending a trigger pulse signal, and when the alternating current crosses zero, the lamp will naturally go out.
However, sometimes it will light up after a power failure or voltage instability, and it can be controlled if you touch the paper or cloth with excellent signal sensitivity.
2. Brightness adjustable type
The working principle of the adjustable table lamp is to form a resistive capacitance phase shift circuit composed of resistor R2, potentiometer RP1 and capacitor C, and adjust RP1 to change the conduction angle of the triac V, thereby changing the brightness of the bulb EL. Resistor R1 is the current limiting resistor. The charging speed of C is also related to the parallel circuit.
In the case of R1 and RP2 fixed, the magnitude of the shunt is determined by the resistance value of the photoresistor RL. When the grid voltage rises, the brightness of the light increases, the RL resistance becomes smaller, the current shunt increases, the voltage rise across the capacitor C slows down, the thyristor V conduction angle decreases, the output voltage decreases, and the brightness of the light decreases; Conversely, when the grid voltage drops, the RL resistance increases, the current shunt decreases, the thyristor conduction angle increases, the output voltage increases, and the light brightness increases. The light brightness is automatically fixed at the set value.