| 摘要 |
PURPOSE:To reduce power consumption and the burden of a main capacitor by setting flash time by the internal impedance of a flash discharge tube, the capacity of a capacitor and the inductance of coil. CONSTITUTION:The output of an AC electric power source 11 charges a main capacitor 13 by way of a rectifying diode element 12, and charges a capacitor 19 for reverse flow by way of an element 23a and a resistance 23b. When a shutter release button is pushed upon completion of this charging to operate a trigger circuit 17, a flash discharge tube 15 and a main SCR16 are triggered and the discharge tube 15 starts emission. At this time, a delay circuit 22 also operates by responding to the operation signal of the circuit 17, but since the circuit 22 has a delay time coinciding with the time required for the entire emission of the discharge tube 15, said circuit generates an output signal at the time when the discharge tube 15 completes the entire emission. This signal energizes a trigger circuit 12 to make the SCR16 nonconducting, thereby shutting off the current flowing in the discharge tube 15. Thereby, the power consumption and the burden of the main capacitor may be decreased. |
