JPS57136171A - Simultaneous measuring device for conductivity and permitivity - Google Patents

Abstract

PURPOSE:To enable simultaneous measuring of conductivity and permitivity of solution to be measured, by a method wherein, from among signals from two electrodes immersed in the solution to be measured, a component, being of an equal phase to that of an AC voltage applied to the electrodes, and a component, which is 90 deg. displaced in phase, are separately rectified in a synchronous manner. CONSTITUTION:If an AC voltage is applied from a power source 5 to two electrodes 1 immersed in a solution 2 to be measured, an output voltage is outputted from a current-voltage conversion circuit 3, and the output voltage is fed to an input terminal of each of synchronous rectifying circuits 4A and 4B. From among the supplied signal voltages, the circuit 4A rectifies only a component, being of an equal phase to that of the output voltage of the power source 5, and outputs it to a smoothing circuit 7A. Then, the output voltage of the circuit 4A attains a value proportioning a solution resistance, and thus, it goes to a value proportioning the conductivity of the solution 2. After the output voltage is smoothed by the circuit 7, it is amplified and is fed to a computer 9. Based on the supplied signal data, the computer 9 finds the permitivity of the solution 2. Meanwhile, the circuit 4B rectifies only a component, whose phase advances 90 deg. as compared with the output voltage of the power source 5, to find the permitivity of the solution 2.