| 摘要 |
PURPOSE:To prevent a phase controller from being operated when no power source is fed to a load side. CONSTITUTION:The LED circuit of a photo-coupler is connected in parallel with a triode AC switch TR, and the output of the photo-transistor PTR of the photo-coupler is fed to a one-shot timer circuit 2. The timer period of the one-shot timer circuit 2 is set to the power source cycle or above, and it outputs an off-signal to a phase control circuit 1 when it is reset. |
