HIGH VOLTAGE FUSE FUSING MELTDOWN CIRCUIT

摘要

PURPOSE:To surely detect and inform the presence of meltdown of many high voltage fuses by comparing the output voltage of inductance with specified threshold voltage. CONSTITUTION:When the short-circuit accident of CRT 13 occurs, short-circuit current flows in CRT 13 from a high voltage power source 1 through inductance 3 to melt down a high voltage fuse 2 and, since the current allowed to flow in the inductance 3 is changed remarkably before and after the meltdown of the high voltage fuse, the voltage proportional to its current change generates between both sides of the inductances 3. And the voltage is divided by resistances R1, R2 to give to the input terminal of the positive side of an operation amplifier 15. Thereby the input voltage VH the positive side of the operation amplifier 15 is more than negative side input voltage Vr, the output of the operation amplifier 15 is changed to a high level, a thyristor 16 is in an ON condition, LED 17 is put on and it is informed that meltdown of the high voltage fuse 2 occurred.