| 摘要 |
PURPOSE: To achieve the reduction of cost and the enhancement of reliability by dispensing with the switch on the input side of an operational amplifier, to dispense with an earth electrode and to simultaneously measure ion concn. and electrode impedance. CONSTITUTION: In an ion concn. measuring device constituted so that the ion concn. measuring signal of a measuring soln. is obtained on the basis of the potential difference between the ion electrode and comparison electrode immersed in the measuring soln., a rectangular wave generating circuit 30 applying AC voltage to the non-reversal input terminal of an operational amplifier Q1, a condenser C4, a resistor R5 and a wiring means applying the AC voltage outputted from the operational amplifier Q1 to the series circuit consisting of the comparison electrode, the measuring soln. and the ion electrode are provided. An electrode impedance measuring circuit 20 taking in the AC current flowing to the series circuit through a DC cut condenser C5 to convert the same to AC voltage and rectifying and smoothing the AC voltage to output an electrode impedance measuring signal is provided. |
