Measurement of tube voltage drop in hot-cathode gas tubes

IN MANY industrial control applications, particularly in process industries, interruptions due to tube failures can be costly. Removal of gas tubes at fixed intervals to insure continuity of service does not improve reliability enough to be a solution. Statistically, a certain group of long-life tubes will be replaced by some short-life tubes. A means of anticipating end of life is, therefore, highly desirable.