Apparatus for measuring conductivity

An apparatus for measuring electric conductivity comprising three electrodes brought into contact with a substance to be measured, said three electrodes including a detection electrode for detecting electric conductivity of the substance to be measured, and two AC current supply electrodes disposed on both sides of said electric conductivity detection electrode at respective distances, an AC current of the same phase being applied to said two AC current supply electrodes, and said apparatus having a space for storing a substance to be measured which is defined between respective electrode surfaces of said three electrodes, and light irradiating means for irradiating light onto the respective electrode surfaces, wherein said space for storing a substance to be measured is defined by a light transmitting material, and light from said light irradiating means is irradiated onto said electrode surfaces through said light transmitting material.

An apparatus for measuring electric conductivity comprising three electrodes brought into contact with a substance to be measured, said three electrodes including a detection electrode for detecting electric conductivity of the substance to be measured, an AC current supply electrode disposed on one side of said electric conductivity detection electrode at a distance, and a grounded electrode disposed on the other side of said detection electrode at a distance, and said apparatus having a space for storing a substance to be measured which is defined between respective electrode surfaces of said three electrodes, and light irradiating means for irradiating light onto the respective electrode surfaces, wherein said light irradiating means comprises a light guiding material which guides light from a light source.

An apparatus for measuring electric conductivity comprising three electrodes brought into contact with a substance to be measured, said three electrodes including a detection electrode for detecting electric conductivity of the substance to be measured, an AC current supply electrode disposed on one side of said electric conductivity detection electrode at a distance, and a grounded electrode disposed on the other side of said detection electrode at a distance, and said apparatus having a space for storing a substance to be measured which is defined between respective electrode surfaces of said three electrodes, and light irradiating means for irradiating light onto the respective electrode surfaces, wherein said space for storing a substance to be measured is defined by a light transmitting material, and light from said light irradiating means is irradiated onto said electrode surfaces through said light transmitting material.