| 摘要 |
<p>1,271,598. Photographic cameras. KONISHIROKU PHOTO INDUSTRY CO. Ltd. Aug. 6, 1970 [Aug. 9, 1969], No.38044/70. Heading G2A. A camera has an electronic flash unit D, an indicator lamp 3 and a photo-sensitive element P, a capacitor which flashes the flash tube 7 being charged upon detection by element 9 of a subject having a brightness lower than a predetermined reference value, the indicator lamp 3 being lit only during the charging of the condenser. During operation of a shutter release, switch 8 is closed, and if the illumination of P is below the reference value, the base potential of TR1 becomes more negative than its emitter potential and TR1 becomes conductive. This in turn switches on SCR2 to commence charging of the electronic flash capacitor via DC/DC converted D 1 . The resulting voltage drop of power source E switches transistors TR2, TR3 to conduct to light indicator lamp 3. Upon the capacitor being fully charged, power source E regains its initial potential, TR2, TR3 cease conducting, and the lamp is no longer lit. Further depression of the shutter release switches over contacts 1 to place element P in an electronic shutter control circuit C. In an alternative arrangement, Fig. 2 (not shown), the completion of the charging of the capacitor is detected by the rise in terminal voltage across the capacitor so as to extinguish the lamp when the capacitor is charged.</p> |
