SCR controlled color changing chandelier circuit

The color-changing chandeliers available on the market have novel and unique shapes and are easy to use. You can change the color of the lamp at will in different occasions, thereby changing the atmosphere of the environment. It can be seen from its structural principle that five milky white lampshades are equipped with red, green, and blue light bulbs respectively. Using the three-color mixing principle of light, multiple colors of light can be mixed. Of course, due to the non-standard color spectrum of the light bulb and the proportional relationship between the brightness of the three primary colors, it is impossible to reproduce the standard white light of the three primary colors and complex colors. But its production principles and design concepts are worthy of reference. The circuit part of the lamp is installed in the lamp and is integrated with the lamp holder, lamp holder, lampshade, etc. It leads to three wires, red, yellow, and green, connected to the equipped switch, which is different from ordinary lamp control. The circuit principle is shown in the figure above. When K in the switch control box is turned on, the 220V AC power is rectified by C1, D1, and D2, filtered by C2 and stabilized by DW, and then supplied to the working voltage of the decimal counting/distributor CD4017. At the same time, the 9V power supply outputs a positive pulse to pin (15) of the IC through C3 to clear the circuit, so its pin (3) outputs a positive voltage to trigger the triac SCR1, causing the red bulbs in the five lampshades to glow. It is a state. If the AN button in the switch box is pressed, the base and emitter of the triode BG are short-circuited, and the BG tube is turned off. At this time, the voltage of pin (14) of the IC rises, triggering the internal circuit to count, and pin (2) outputs a high level. , causing the bidirectional thyristor SCR2 to conduct, causing the corresponding five green lights to light up. Press AN again, and the circuit can light up the blue light again. When you continue to press AN to make the IC pin (7) output a high level, the red and green bulbs in the lampshade will light up at the same time, thus appearing as yellow light to the outside. Readers can analyze the output of each pin of the IC and the color of the light by themselves. When diode D3 makes pin (6) output, the circuit is reset to the initial state, that is, the red light is on. D4~D12 are isolation diodes. When selecting 25W colored bulbs, the triac should be selected with 2A current. In addition, it is easy to find that all colored lights cannot be turned on during use. This may be due to damage to the step-down rectifier circuit, such as C1, D1, D2, DW, etc. According to the circuit, a 2K thyristor should be connected in series to each of the three thyristor control poles. resistor to protect the thyristor and CD4017. When installing the wiring, the wiring between the lamp and the switch box cannot be connected incorrectly, as it is already color-coded.