Bidirectional thyristor stepless dimmer with light stabilizing function

S2 in the circle is an automatic light stabilizing switch. When S2 is turned on, the entire circuit is the thyristor stepless dimmer introduced in Section II
, except that the high-frequency filter circuit is omitted and the trigger diode is replaced with a neon bubble V to adjust The potentiometer RP1 can
adjust the brightness of the electric lamp H as desired. At this time, the neon bubble V can emit a red glow and can act as an indicator light. At this time, the circuit
does not have a light stabilizing function. When automatic light stabilization is required, you can press switch S2. At this time, the resistor (R2+RP2+RG) is connected in parallel with the capacitor
C. It and (RI+RP1) jointly determine the charging rate of the capacitor C. On the one hand, the charging rate of capacitor C
is determined by (Rl+RPl), so adjusting the resistance of RPI can still be said to save the brightness of lamp H; the charging rate of capacitor C is also affected by the (R2+RP2+RG)
branch, where RG is The resistance value of the photoresistor changes due to changes in the ambient illumination. When the ambient illumination
is high, RO has a low resistance, so the charging rate of the capacitor C slows down, the conduction angle of the thyristor vs. the light becomes smaller, and the light resistance decreases. The luminous brightness of H
decreases. If the ambient illumination gradually decreases, the shunting effect of this branch decreases, so the charging rate of capacitor
C accelerates, the conduction angle of thyristor vs gradually increases, and the brightness of lamp H also increases. , so as to ensure that the illumination of the illuminated working surface is stable
.