The principle of the touch table lamp is to install an electronic touch IC inside, and form a control loop with the electrode sheet at the touch point of the table lamp.
When the human body touches the sensing electrode sheet, the touch signal is generated by pulsating direct current to send a pulse signal to the touch sensing terminal, and then the touch sensing terminal will send out a trigger pulse signal to control the lighting; touch again, the touch signal will be pulsated again The direct current generates a pulse signal and transmits it to the touch-sensing terminal. At this time, the touch-sensing terminal will stop sending out the trigger pulse signal. When the alternating current crosses zero, the lamp will go out naturally.
However, sometimes it will light up by itself after power failure or unstable voltage, and it can also be controlled if you touch paper or cloth with excellent sensitivity to received signals.
The working principle of the adjustable table lamp is a resistance-capacitance phase-shift circuit composed of a resistor R2, a potentiometer RP1, and a capacitor C. By adjusting RP1, the conduction angle of the bidirectional thyristor V can be changed, thereby changing the brightness of the light bulb EL. Resistor R1 is a current limiting resistor. The charging speed of C is also related to the parallel circuit.
When R1 and RP2 are fixed, the size of the shunt is determined by the resistance of the photoresistor RL. When the grid voltage rises, the light brightness increases, the RL resistance value decreases, the shunt increases, the voltage across the capacitor C rises slowly, the thyristor V conduction angle decreases, the output voltage decreases, and the light brightness decreases; otherwise, when the grid When the voltage drops, the RL resistance increases, the shunt decreases, the thyristor conduction angle increases, the output voltage increases, and the light brightness increases. The light brightness automatically stabilizes at the set value.