One of the incandescent lamp dimming circuits using thyristors b

(1) One of the incandescent lamp dimming circuits using thyristors.
    The circuit is shown in Figure 2-66. Figure 2-66 (a) Using the method of combining thyristor half-
wave controllable dimming and diode dimming. When the switch SA is turned
to the "3" position, adjust the potentiometer RP, and the voltage at both ends of the bulb
changes in the range of 20-100V; when SA is turned to the "2" position,
the bulb emits light at a brightness of approximately 1/4 of the rated power; When SA hits the "1" position
, the bulb is fully lit. Figure 2-66(b) only uses pin-gate dimming, and a light bulb with a rated voltage of 11V can be used.