| 摘要 |
<p>PURPOSE:To suppress the power consumption of a battery and to save the energy by feeding the driving current of a switching means which controls the charging of a main capacitor only in the operation time of a boosting circuit. CONSTITUTION:When a photographic information input switch 21 is off, the boosting circuit 3 charges the main discharge capacitor 5 through diodes 4 and 9 and also flows a current to the base of a transistor (Tr) 19 through a diode 22 and a resistance 23 to turn on the Tr19. Consequently, a Tr16 also turns on to turn on a thyristor 12, charging the main discharge capacitor 10. When the charging voltage of the capacitor 5 rises up to a specific voltage, the circuit 3 stops operating to cut off the current supply, and the Trs 19 and 16 turns off to flow no gate current to the thyristor 12, so that unnecessary power consumption after the charging is prevented. When the switch 21 is on, on the other hand, the capacitor 5 is charged, but no base current of the Tr19 flows from the circuit 3 through the diode 22 and resistance 23 and the Tr does not turn on, so either the Tr16 nor the thyristor 12 turns on, so that the capacitor 10 is not charged.</p> |
