HIGH VOLTAGE FLASH DETECTION

摘要

A method and device are described for detecting whether a flash (F) has occurred in the high voltage part of a combined high voltage and horizontal deflection circuit (100) in an apparatus comprising a cathode ray tube (CRT), such as for instance a television set, a monitor, etc. The possible flash is detected by checking the fly-back pulse (70) of the horizontal deflection circuit (16) for deviations that reflect the occurrence of a flash. One possible distortion indicative for the occurrence of a flash is bouncing of the fly-back pulse. Another possible distortion indicative for the occurrence of a flash is collapse of the fly-back pulse. Another possible deviation indicative for the occurrence of a flash is a substantial decrease of the storage time ( tau S)) of the line deflection transistor (30).