Study on demagnetization characteristics of magnetic shielding plate in cathode ray tube

An inner magnetic shield (IMS) is set inside a cathode ray tube (CRT) to reduce any external disturbance, and ac demagnetization is applied at every switch on of CRT. In this paper, the problem in measuring an anhysteretic magnetization process is investigated, and the demagnetization characteristics of IMS are measured. It is shown that the Hall probe which is used in a Gauss meter is effective for the accurate measurement of very low dc field, like geomagnetism.