| 摘要 |
1,252,727. Photo transistor bias circuits. STANDARD TELEPHONES & CABLES Ltd. 21 April, 1970, No. 18977/70. Heading H3T. The current through a photo transistor having a capacitive output coupling is stabilized at a low level despite changes in ambient light by a feedback transistor arranged between base and emitter as shown. The circuit illustrated is for triggering an electronic photographic flash unit in response to the light from a second flash. |
