| 摘要 |
1466131 Shutter control circuit ASAHI KOGAKU KOGYO KK 15 May 1974 [15 May 1973] 21578/74 Heading G2A [Also in Division H3] A shutter control circuit comprises a first transistor 9 having a first constant voltage source 10 connected to its emitter and a timing capacitor 8 connected to its collector, and a second, complementary transistor 6 coupled to a second constant voltage source 7 of similar construction to the first source 10; the second source 7 being manually set in accordance with a desired shutter time and the second transistor 6 being coupled in emitter-follower fashion to the first transistor 9 to charge the timing capacitor 8 and control a shutter closing electromagnet 13 via a switching circuit 12. Preferably an automatic timing arrangement comprising a third transistor 2, a photodiode 1, a constant voltage source 3 set according to aperture and film speed and a buffer circuit 4 is connectable to transistor 9 by an auto-manual selector switch D. |
