| 摘要 |
PURPOSE:To suppress an excessive flow of lamp load without connecting a large size of parallel element by continuing a thyrister in a specific time by the phase control to feed a specific power to an AC load when an operation switch is in an opened condition. CONSTITUTION:When a switch 2 is opened, a photothyrister 4b is OFF, a transistor 8 is ON, and a thyrister 9 is OFF. However, a condensor 20 is charged through two resistances 18 and 19 at every half wave of an AC power supply 10, and when it reaches the operating voltage of a PUT 17, the PUT 17 is continued to generate pulses, and thereby the thyrister 9 is ignited, a triac 12 is ignited, a phase-controlled voltage is applied to a lamp load 11, and the lamp load 11 is preheated. By closing the switch 2 after a specific time passes, the photothyrister 4b is ON, the transistor 8 is OFF, the thyrister 9 is ON, the triac 12 is ignited, a full-wave wave form of voltage is applied to the lamp load 11, and a full load current flows to the lamp load 11. |
