Thyristor three-tone lighting circuit

The circuit of the three -tone diodes light bulb is shown in Figure 38. It only uses one potentiometer to control the on and off of three light bulbs: red, green and blue.     The 220V alternating current is rectified by the VDl-VD,1 bridge and outputs a pulsating DC voltage, which is added to both ends of the lamps El-F3 and the unidirectional thyristors VTl-VT3 that control them respectively. When the sliding end of the potentiometer RP moves to the uppermost end , the DC la source is added to the two voltage dividers composed of Yue and R, and Chi 2 and R through F3 and RP. At this time, the voltage at both ends of Chi and R is the highest, and the thyristor VT2 is turned on, and the red light bulb El lights up. E3 solid current is very small and does not emit light. When moving the RP sliding end downward, R. The voltage at both ends gradually decreases, that is, the emitter junction voltage of transistor VT4 increases. When it increases to 0.6jV, VT4 is turned on, the gate tube VT1 is turned on, and the green bulb F_2 lights up; as the RP sliding terminal goes down, when R, when the voltage at both ends drops to a fixed value, VT2 is turned off and the red light E1 goes out. When the sliding end of RP continues to move downward, the resistance decreases, and the voltage at both ends continues to increase, thus making the conduction angle of thyristor VT3 continue to increase, and finally the blue bulb F3 is fully lit, and at this time El and E2 are both extinguished.     V¨-VT3 can use small sealed one-way thyristors such as BD169D, 2Nfi565, MCR100-S, etc., and can use red, green, blue and other colors with a power of no more than 60W according to each preference at 1:3. Bai Si light bulb. There are no special requirements for other components.