Detection of water amount on the surface of glass fibers using the transient leakage current of static electricity

A bundle of fibers (each 20 /spl mu/m in diameter) was sandwiched by electrodes, and a high voltage of 400 V was supplied to the electrodes to measure the leakage current flowing on the surface of the fiber. The leakage current is as low as the order of mA. It was demonstrated that the current is almost linear relative to the water amount on the surface of the fibers in the examined range from 0.08 to 1.2% weight percent. This range is very important for the inspection of the fibers during the production stage in factories. A simple and practical instrument for detecting the amount of water is also presented.