| 摘要 |
1286927 Photographic camera shutter control ASAHI KOGAKU KOGYO K K 19 April 1971 [11 May 1970] 25959/71 Heading G2A An electric shutter control for a camera comprises an emitter follower circuit Q 2 and a logarithmic expansion circuit Q 3 coupled to a photovoltaic element D through a buffer circuit Q 1 , the load resistance R F A SA of the emitter follower circuit being determined by the diaphragm value and film sensitivity so as to accomplish photographic computations. During exposure, a charging current i is applied to a capacitor C until the voltage thereon equals the trigger level of a switching circuit including transistor Q 4 , whereupon thyristor Q 5 fires to short circuit electromagnet M. |
