| 摘要 |
PURPOSE:To reduce the watt loss at standby time by turning ON or OFF a switching element with the terminal voltage of a smoothing capacitor as a discriminated voltage and deciding the lowest level of the terminal voltage of the capacitor. CONSTITUTION:An AC power source waveform fed through a rectifying diode 2 is fed through a switching element 3 such as an SCR, and a dropper resistor 4, and converted by a smoothing capacitor 5 into a DC voltage. The terminal voltage of the capacitor 5 is monitored by a constant-voltage diode 8, and when it becomes the prescribed value or higher, the element 3 is set to OFF state to stop charging of the capacitor 5 performed through the resistor 4 from an AC power source 1. If the terminal voltage of the capacitor 5 becomes the prescribed value or lower, the element 3 is again set to ON state to charge the capacitor 5 until the terminal voltage of the capacitor 5 becomes the prescribed value. |
