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Camera capable of measuring power source voltage

  • US 5,701,527 A
  • Filed: 12/21/1994
  • Issued: 12/23/1997
  • Est. Priority Date: 12/27/1993
  • Status: Expired due to Term
First Claim
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1. A battery check device for a camera, comprising:

  • a discharging circuit to which current flows from a battery;

    discharging time setting means for setting a discharging time for determining that an internal resistance of the battery has increased due to non-use of the battery so as to temporarily reduce an output voltage of the battery, said discharging time being longer than a time required to check a residual energy amount of the battery;

    determining means for determining whether a voltage of said discharging circuit has reached a reference voltage specific to the battery within said discharging time; and

    mode state determining means for determining whether an operating mode of a camera remains in a normal mode in which the camera performs a normal photographic sequence or whether the operating mode of the camera has been changed to the normal mode from a power-saving mode in which the camera consumes less power than in the normal mode;

    wherein said discharging time setting means includes;

    (i) means for setting a discharging time corresponding to the time required to check the residual energy amount of the battery when said mode state determining means determines that the operating mode of the camera remains in the normal mode; and

    (ii) means for setting said discharging time for determining that the internal resistance of the battery has increased due to non-use of the battery when said mode state determining means determines that the mode of the camera has been changed to the normal mode from the power-saving mode; and

    wherein the residual energy amount of the battery is determined to be insufficient when said determining means determines that the voltage of said discharging circuit has not reached the reference voltage specific to the battery within said discharging time.

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