| 摘要 |
PROBLEM TO BE SOLVED: To prevent a phosphor from being backed by a beam spot, by quickly reducing a grid bias voltage of a cathode-ray tube to cut-off the beam when scanning of the electron beam of the cathode ray tube is lost. SOLUTION: A grid kick circuit that supplied a cut-off bias to a grid G1 when scanning of an electronic beam is lost in a cathode ray tube 10 uses a 1st voltage source (+200 V) to charge a grid kick capacitor CK to a prescribed voltage and adjusts the voltage of the grid G1 to a prescribed voltage fixed, depending on a 2nd voltage source (+12 V) when no beam blanking is required and gives a voltage produced between both terminals of the capacitor CK to the grid G1, to quickly cut off the beam. This method especially improves the charging efficiency of the capacitor.
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