| 摘要 |
PROBLEM TO BE SOLVED: To measure resistance values with accuracy by taking one current valve of either the charging current or discharge current of a capacitor as a constant current proportional to the inverse number of a resistance value through the use of a known resistor and a resistor to be measured with a unknown resistance value. SOLUTION: A capacitor C is recharged by a constant current from a constant-current power source. A hysteresis comparator 11 detects that the interterminal voltage of the capacitor C reaches a predetermined threshold value by recharging. By this detection, a one shot multivibrator 12 outputs a pulse to close a switch S for a predetermined time. By this, the electric charge recharged in the capacitor C is discharged to returned to the initial state. Sawtooth waves are generated by repeating operations. Recharge time tc is in inverse proportion to the resistance value of a resistor to be measured regulating the value of the recharging current outputted from the constant-current power source. Therefore, by measuring an oscillation frequency regulated by the recharge time tc or the recharge time tc and discharge time tdc, it is possible to measure the resistance value of the resistor to be measured.
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