Dual color light circuit

This lantern uses a multivibrator as the control signal. The lights shine alternately, which can add a lot of brilliance and cheerful atmosphere to festive evenings (especially dance parties). The working principle is shown in the figure below. After the AC 220V power supply is stepped down, rectified and filtered by C1, VD1, VD2 and VD3, a stable voltage of 3V is obtained at both ends of VD3. VT1 and VT2 in the multivibrator are turned on in turn, and their collector current controls the operation of the bidirectional thyristors VS1 and VS2, and the colored lights will flash alternately. Component selection: Capacitor C1 is 0.47μ/400V (polyester capacitor), C2 is 220μ/6V, C3 and C4 are 50μ/16V. Resistor R1 is 1M/1W, R2 and R3 are 20K/1/4W. Choose 1N4004 for diodes VD1 and VD2. The voltage stabilizing diode VD3 is selected to be 3V/1W. The light-emitting diodes VD4 and VD5 are FG114001. The bidirectional thyristors VS1 and VS2 are TLC3A/400V. Transistors VT1 and VT2 are 3CK9D, 60≤β≤120. Instructions for use: (1) If the colored lights do not light up, replace the 3V voltage regulator tube with a 4.5V voltage regulator tube. (2) In order to prevent the current flowing through the light-emitting diodes VD4 and VD5 from being too large, it is best to insert a 300Ω current-limiting resistor in series with each of the light-emitting diodes VD4 and VD5. (3) When adjusting, changing the size of R1, R2 or C1, C2 can directly control the speed of the lanterns changing to each other. (4) If the bidirectional thyristors VS1 and VS2 use 3A/400V, the load power should be below 300W and should not exceed the maximum limit of 500W. If you want to increase the power, you can use a thyristor with a current greater than 3A, but the capacity of C1 needs to be increased. If the original 0.47μ/400V is used, it can be replaced with 0.68~1μ/400V. (5) This device uses plastic as the outer casing to avoid electric shock to people from the mains power supply, which is safer.