Stage thyristor dimming circuit 2

(2) Stage thyristor dimming circuit 2
    The circuit is shown in Figure 2-82. It uses a trigger circuit composed of a single-junction transistor VTi and a resistor-capacitor element, which is amplified by the transistor VT2, and controls the conduction angle of two thyristors (connected in reverse parallel)
through the pulse transformer TM to achieve the purpose of dimming.