| 摘要 |
PURPOSE:To apply the titled device for a copying machine, etc. and to facilitate digital processing with a simple constitution, by regarding a last ignition phase angle as a current reference value according to a difference between a detected value and a desired value, and then obtaining a current ignition phase angle by addition or subtraction. CONSTITUTION:A load electric power detector detects the effective value of a load voltage or current, an A/D converter converts a detected value into digital data, and a switching device powers up and down a load. Further, a zero- cross detector detects the zero-cross point of a power voltage, and a phase controller compares a detected value with a desired value and then determines the ignition phase angle of the switching device on the basis of the zero-cross point as a reference point according to the difference between both the values. According to the difference between the detected value and desired value, a last ignition phase angle is regarded as a reference value and addition to or subtraction from it is performed to set a current ignition angle. |
