Production of energy-saving light-controlled switch circuit

At present, there are many circuits for light-controlled switches, but there are also some problems. For example, when the light is controlled, the light will flicker during the light-dark conversion process, which affects the life of the light, especially energy-saving lamps are more susceptible to damage. At the same time, the rhyme circuit consumes a lot of power. In view of the above situation, I designed a light-controlled switch. It uses a capacitor step-down circuit to effectively reduce power consumption.

At the same time, the use of a time-based integrated circuit makes the light less likely to flicker.

Working principle The circuit diagram is shown in the figure. The 220V AC voltage is stepped down by capacitor C3, rectified by diode VD1, stabilized by voltage regulator VD2 and filtered by capacitor C2, and a stable voltage of 6V is output for use by the light control circuit. IC and foreign components form a light control circuit. During the day, when the light is strong, the resistance of the photoresistor RG is small, the input pins 2 and 6 of the IC are high, and the output pin 3 is low. There is no current passing through the control pole of the thyristor VS, and the energy-saving lamp does not light up. When night falls, the resistance of the photoresistor increases. When the resistance increases to a certain value, the input pins 2 and 6 are low and the output is high. At this time, there is current passing through the control pole of the thyristor, and the energy-saving lamp lights up. When the day of the next day comes, the resistance of the photoresistor gradually decreases, and the input pins 2 and 6 are high again, the output is low, and the energy-saving lamp goes out. The principle of the light not flickering is: when the light is about to go from on to off or from off to on, the input pin 2 of the IC will be high and the pin 6 will be low (relative to the internal comparator), and the output will maintain the original high or low level. When the light goes from on to off or from off to on, the input pins 2 and 6 are both high or low, that is, the output changes from high to low or from low to high. At this time, even if the input level is unstable, the output level will not change, thus avoiding the flickering of the light.     

Component Selection and Manufacturing IC uses the time base circuit NE555. The step-down capacitor C3 uses a 0.33μF/400V polyester capacitor.

The thyristor VS is 1A/400V (optional model is MAC97A6). The voltage regulator VD2 is 6V/0.5W. The photoresistor RG is a normal light resistance <10kΩ, dark resistance >2MΩ. The energy-saving lamp is 5W~20W.

When making it, make a circuit board as shown below.

After the components are correctly welded, connect the circuit and the lamp, and connect the ground wire and the live wire as required in the diagram. After power on, use a multimeter to measure the voltage across capacitor C2, which should be 6V. If the voltage is 0V, it means the voltage regulator is broken. After the voltage is normal, use black tape to stick on the photoresistor, and the light should light up. When the tape is removed, the light should go out, indicating that the circuit is basically normal. Then, use a multimeter to measure the thyristor control electrode current, which is about 3mA, which is normal. If the current is greater than 5mA, the resistance of R3 should be reduced.

Finally, find a plastic shell (you can also use a sound and light control switch shell instead). Make a small hole in the plastic shell so that the surface of the photoresistor can be exposed. In this way, the energy-saving light control switch is made. When installing, it is best to find a place where natural light can easily shine, but light can not shine, and do not install it in a place where rain can hit it. If you find that the light is not satisfactory during use, you can change the resistance value of R1 appropriately.