| 摘要 |
In a camera having a light-integrating, timing circuit for determining shutter speed in accordance with the intensity of scene illumination, a circuit is provided for determining whether the scene illumination is below a predetermined value and for determining the condition of the power source to be inserted in the timing circuit. The test circuit includes an indicating means such as a lamp, a first switch for energizing the lamp, an element whose impedance is dependent upon incident scene illumination, and a second switch which serves to turn "on" the first switch when scene illumination incident upon the element falls below a predetermined value. The test circuit further includes a circuit element (or combination of circuit elements) responsive to the potential of the energizing source, for preventing the second switch from turning "on" the first switch when the potential of the energizing source is below a predetermined value.
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