Three-way flashing light string circuit (3)

It is a three-way flashing light string controller composed of three ordinary bidirectional thyristors , which can make the light string
light up cyclically. The maximum output power of each channel can reach 1000W. The circuit is simple and easy to make.
    Due to the discrete nature of the parameters of electronic components,
after the 220V AC power is turned on, there is always a thyristor
that is turned on first. Assume that the 220V alternating current is half-wave rectified by the light string El and
VD1, and through R, the direction of (j is first charged to
the non-f J level of the VTfl2 gate , VTH2 is turned on, and
the light string E2 lights up; therefore, the first anode of VTH2
is low-voltage. flat, (1. Unable to charge, VTH3 is turned off, and
E3 goes out. At this time, the first anode of VTH3 is at a high level
, and the 220V AC power can be rectified by E3 and VD3,
and charged to G via the ruler s, so that the VTH] gate level gradually Rise, when it rises to a certain value, VTH1 is turned on,
El is energized and emits light, and the first anode of VTH1 is at a low level, causing VTH2 to lose the trigger current and turn off, so
F2 goes out. At this time, the first anode of VTH2 is at a high level. level, the power supply charges to G through E2, VD2, R, so
the gate level of VTH3 gradually increases, eventually VTH3 will be turned on, E.3 will light up, the first anode of VTH3
will be at a low level , and VTH1 will be turned on due to the gate The pole loses the trigger current and turns off, E] goes out...so the light string L
will light up in a cycle according to the E2- E1-E3-E2-El-- timing sequence. The cycle rate is determined by the resistor R. (R. or R.) , Capacitance C.
(o or bar) is determined by the value. The larger the value, the slower the speed, and vice versa. Generally, it is appropriate to increase or decrease the capacity of the capacitor,
(1, ((five or c;)) can be selected between 3 3-20yF .
    VD】- vD3 can use 1N1007 ordinary silicon rectifier diode. VTHl- VTH3 uses 5A,
600V bidirectional thyristor, the maximum load power can reach 1000W, and it is required to install a sufficient aluminum
heat sink plate for the thyristor. R. , R. and R. use RJ-2W] 2kn metal film resistors, R,, R. and wind use RJ-2W
iOkn metal film resistors. (1.~G requires the use of electrolytic capacitors with a withstand voltage of 400V or higher.