| 摘要 |
An electrical shutter control circuit of the type which is integrated directly is disclosed. The light receiving element is connected across the input terminals of an operational amplifier, and a switch connects one of at least two integrating capacitors between the output and the inverting input of the operational amplifier. The switch is switched in accordance with a selected ASA sensitivity range. The resistance of a variable resistor is set in accordance with a selected ASA sensitivity and is mechanically coupled with the switch. A comparator compares a voltage corresponding to a selected ASA sensitivity as determined by the resistance of the variable resistor with the integration voltage at the output of the operational amplifier to control the shutter speed. The circuit has a high accuracy throughout a wide ASA setting range and is operated by a low supply voltage.
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