| 摘要 |
PURPOSE:To keep power supply to a load constant independently of the difference of power supply frequency by selecting and switching two different time constant circuit externally in accordance with commercial power supply. CONSTITUTION:A power supply circuit 1 applies voltage through full-wave rectifier circuits D1-D6 to a zero crossing detecting circuit 2 and a pulse signal to a pusle width control circuit 3. The circuit 3 converts the received signal into a pulse having prescribed pulse width in its time constant circuit W1 and supplies the pulse to a pulse transformer 14 in a trigger circuit 5 through a time constant circuit W2 in a trigger pulse generating circuit 4. the transformer 14 drives a load driving circuit 6 consisting of a triode AC switch 15 to make current flow into a load 16. The time constant circuits W1, W2 convert the inserting positions of a plug 11 of a connector 12 in accordance with power supply frequency, 50Hz e.g., to select and switch resistors R7-R'8. Thus, the electric power to be supplied to the load 16 can be kept at constant independently of the difference of power supply frequency. |
