Thyristor two-tone lighting circuit (1)

The circuit of the thyristor intense dimmer is shown in Figure 36. In the figure,
the circuit consists of VD3, V【)4, R, RP and C. The capacitor with constant resistance in the positive and negative half cycles is charged in
the same path (when Except for the RP sliding end located at the center). As a result, the conduction angle of
the bidirectional thyristor VTH is different in the positive and negative half cycles .
Then through the guidance of diodes VI)l and VD2
, E1 and E2 work respectively in
two half-cycles. When the sliding end of the potentiometer RP
moves to the right by R, f, the conduction angle of the thyristor VTH increases in the positive half cycle
and decreases in the negative half cycle, so
the brightness of the lamp Fl increases and the brightness of the lamp E2 weakens; if the potential When the sliding end of the device
Rf' moves to the left, the conduction angle of the thyristor VTH increases during the negative half cycle and decreases during the positive half cycle,
the brightness of the lamp Fl weakens, while the brightness of the lamp F,2 increases. When the sliding end of the potentiometer RP is at the center position,
the charging time of the solid capacitor C in the positive and negative half cycles is the same, the conduction angle of the gate tube VTH in the positive and negative half cycles
is the same , and the brightness of the lamps El and E2 Same. From this, she can adjust the potentiometer RP to make the red light El (or green light E2)
gradually brighten, and the green light E2 (or red light El) gradually dim until it turns off. This dimmer can be used
as a desk lamp or wall lamp to embellish and beautify the indoor environment. VTH can use small bidirectional thyristors
    such as TI, C22lB or MAC94A4 . VD1~VD4 can use lNl4007 type silicon rectifier diodes. VIJH is a ZCTS type bidirectional trigger diode, which requires a folding voltage of about 30-39V. RP uses a rotary shaft or sliding rod type linear potentiometer with a push-pull power switch , R is an Rj-l, /2W type, which is a film resistor, and C uses a polyester or metal film paper dielectric device with a voltage of 300v. Fl and E2 can be red, green or other colors of incandescent bulbs with a power of 60W or less depending on what everyone likes.