| 摘要 |
PURPOSE:To improve reliability and reduce deterioration of elements by a method wherein the elements are combined which are changed in the value of resistance by a phase shifting circuit, arc circuit and lights. CONSTITUTION:When a light emission diode 18 does not emit light, Cds cell 19 has high resistance and therefore, a capacitor 9 is charged almost without by-passing of the charging currents to the capacitor 9. When voltage of the capacitor 9 reaches a given value, a silicon bilateral switch (SBS) 6 operates switching, so that only short time is required before triggering the gate of triac 5 and accordingly, the angle of the arc phase is narrow. On the contrary, when a large quantity of light is irradiated from the light emission diode 18 and the valve of resistance of Cds 19 cell is small, the angle of the arc phase of triac 5 becomes large. |
