| 摘要 |
<p>A photoresistor (9) is connected to the input of a comparator circuit (23, 22) and an electro-magnetic motor (16) for controlling the aperture (14). Light striking the photoresistor is connected to the comparator output. As light levels change an imbalance in the comparator causes the motor to drive and adjust the aperture to restore equilibrium. A three input OR-gate (24) is connected to the comparator circuit and its output is connected to a switching transistor (6). Unsuitable light levels switch the transistor off, through the OR-gate, a relay (3) drops out and its contact (7) disconnects the film transport motor (8).</p> |
