Make a holiday light controller with SH-868

The holiday lantern controller circuit made with SH-868 is shown in Figure 2-82. The circuit
consists of a flash integrated circuit, a thyristor drive circuit, an audio power amplifier and a power supply circuit. The 220V AC power is stepped down by Cl, rectified by VD2, stabilized by VD3, filtered by
    C2, C3 and R3 and outputs about 4.7V DC voltage supply. The integrated block A uses power. R1 is to prevent the CI charging current from being too large when it is first powered on and may burn the voltage regulator tube. The buffer resistor is set by VD3 . VT1 and VT2 form a complementary OTL power amplifier circuit to amplify the music signal output by the integrated block. Its power supply is taken from the left part of the filter resistor R3 to obtain a higher DC operating voltage. The output terminals 13~16 of the integrated block A are directly connected to the gates of the thyristors VSI-VS4 to control the flashing of the colorful light strings HI~H4. SB is the function selection switch. Each time it is pressed, one function can be changed. There are seven flashing functions available (see the previous section).