The Influence of the Cathode Heating System of the Inverter Ballast on the Position of the Cathode Spot

Abstract

Recently, fluorescent lamps having a higher output and longer life have been developed in the field of residential lighting. If lamp life can be estimated by measuring electronic signals such as lamp current and cathode heating current, the estimation would be very useful for designing lamp operating systems. To estimate lamp life, it is very important to know where the light-spot position, which is the spot that emits electrons, exists on the cathode. It was reported that the light-spot position for one operating system could be located by measuring the electronic signals. However, there are many kinds of electronic circuits for use in fluorescent lamp operating systems. It has not been confirmed whether this method for locating the light-spot position is useful for other kinds of electronic circuits. In this paper, the authors reveal that the method mentioned above is useful and that the way of heating the cathode in the electronic circuit influences how the spot moves as burning time passes.