It should be a touch light.
Touch lamp is a kind of lamp, by touching the metal part of the lamp can control the lamp on and off and brightness, long service life, very power saving.
Touch lamp By touching the metal part of the lamp can control the lamp on and off and brightness. At the same time, the control function can be realized by keying. The design mainly uses analog circuit, digital circuit and power electronics related knowledge. At the same time, PCB design knowledge and software are also used in the process of manufacturing circuit boards.
Touch light design
The working process of the touch table lamp is to form a control loop between the internal installation of an electronic touch chip and the electrode at the touch of the table 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; If you touch it again, the touch signal will be transmitted to the touch sensing end by pulsating direct current to generate a pulse signal, at this time the touch sensing end will stop sending a trigger pulse signal, and when the AC current passes zero, the light will go out naturally.
Touch light principle
When the switch is turned on, the power supply voltage is added to the unidirectional thyristor after the lamp and full wave rectification, and at the same time, the capacitor C1 is charged by R1 and W1. When the voltage on C1 is charged to greater than the on-voltage of the single-junction transistor, BT33 is broken down, and the capacitor C1 is discharged by BT33 and R3, and this discharge current forms a trigger voltage on R2, so that the unidirectional thyristor is switched on, thereby providing a luminous current for the lamp. The voltage that charges C1 after full wave rectification is a 100Hz pulsating DC voltage. Because the voltage on the capacitor lags behind the current in phase, and the time of this lag depends on the RC time constant, when the voltage on C1 is lower than the breakdown voltage of BT33, there is no current flowing on R2, and the trigger foot of the thyristor has no contact voltage. The time required for the capacitor voltage to go from zero charge to breakdown of the single junction transistor is related to the RC time constant. When W1 is adjusted, the equivalent time constant is changed. When W1 resistance is small, the voltage on C1 will quickly break down BT33. In this way, the morning and evening of the spike time on R2 can be controlled, and the conduction Angle of the unidirectional thyristor can be controlled, so as to realize the light control of the table lamp.
Some light bulbs light up without being charged because they use an electrical supply system to work. This type of bulb is usually lit by turning on the power supply, and when the current passes through the resistance filament of the bulb, the electrical energy is converted into heat and light energy, which makes the bulb glow.
Compared to a lamp that needs to be recharged, this power supply system gives the lamp the ability to glow in real time, without waiting for the charging process.
Therefore, these bulbs only need to turn on the power switch when they need to be used, and the current will flow through the bulb, making it instantly light up.
This design makes the use of these bulbs more convenient and convenient.