| 摘要 |
PURPOSE:To evade the unbalance of a degaussing magnetic field when a power source circuit uses a half-wave rectification type and prevent a cathode-ray tube from being magnetized by changing operating parts of a degaussing coil in the positive and negative half cycles of an AC power source. CONSTITUTION:The number of turns of a degaussing coil 5 is N', a tap 5a is formed at the (N)th turn from the side of a posistor R1, and a diode D is connected thereto. Therefore, the diode D turns on in negative half cycles of the AC power source to operate only some part of the degaussing coil 5 corresponding to the number N of turns, and the other part corresponding to the number (N'- N) of turns does not operate. Further, the diode D turns off in positive half cycles of the AC power source to operate the whole of the degaussing coil 5 corresponding to the number N' of turns. Thus, the undesirable magnetization of the cathode-ray tube of a television receiver which has a half-wave rectification type power source circuit is eliminated by the degaussing circuit. |
