Apparatus for measuring the electrical conductivity of a liquid medium

A use of a device for measuring electrical conductivity of a liquid medium, comprising:

• constant voltage means connected to a first electrode arrangement for injecting an alternating signal into the liquid medium,
• detection means connected to a second electrode arrangement, which is separated from the first electrode arrangement and which is coupled via the liquid medium, said detection means generating a measurement signal (U(U)) influenced by the electrical conductivity with a clock frequency (CLK) of the alternating signal, and
• evaluation means, which from a current-proportional injection signal (U(I)) of the current injected by the first electrode arrangement into the liquid medium and from the measurement signal (U(U)), generate a conductivity signal of the liquid medium, and make it available for further electronic processing,
• wherein the constant voltage means are made in an individual circuit branch which has commutator means for the first electrode arrangement and ohmic resistance means in a series connection, and the current-proportional injection signal (U(I)) being tapped as a voltage drop over the resistance means, and
• wherein the conductivity signal has an uninterrupted range of conductivity between 0.001 mS/cm and 1000 mS/cm.