| 摘要 |
PURPOSE:To make it possible to prevent variation in phase angle due to variation in the line frequency, by constituting a phase angle control circuit with a unit phase angle pulse circuit, phase angle timing circuit, and phase angle control signal output circuit. CONSTITUTION:A unit phase angle pulse train which is given by dividing the power source cycle into unit phase angle cycles of the same distance is output form a counter 38, and in a multiplication circuit 32 the number of unit phase angle pulses in one cycle and a phase angle set value that is beforehand given are multiplied to seek the time of timing up to a phase angle set value. Further, a phase angle control signal is output by a phase angle control signal output circuit 34, when the basic clock pulse 800 of a frequency determined based on the unit phase angle cycle and the number of unit phase angle pulses in one cycle is counted for the time of timing. In this way, the circuit is made to require no adjustment by only determining beforehand the phase angle setting value. |
