| 摘要 |
PURPOSE:To flexibly cope with the change in the supply voltage of a battery, etc., by making the switching of the connected number of diodes of a voltage dividing circuit which divides a supply voltage and contains a serial circuit of plural diodes and resistances possible. CONSTITUTION:The output voltage VA of a constant-voltage circuit A becomes constant when it is higher than the voltage V of a battery E. The electric potential VB at a connecting point Q can be changed when the connection between a connecting terminal H and one of connecting terminals B1-B(n+1) and the number (n) of diodes is changed, and the electric potential can be expressed by a formula VB=(V-nVD).r2/(r1+r2). A comparator B sends a low-level signal and judges that the battery E is normal when the electric potential VB is higher than the voltage VA, and sends a high-level signal and judges that the battery E is abnormal when the electric potential VB is lower than he voltage VA. Therefore, by connecting an indicating lamp to the output terminal of the comparator, abnormal conditions of the battery E can be recognized.
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