| 摘要 |
PURPOSE:To assure degaussing and at the same time to a void repeating unnecessary degaussing by closing a switch for degaussing in response to a case where the rectifying voltage of an alternator, i.e., a rectrifying circuit is set higher than a prescribed level. CONSTITUTION:When an engine key switch is switched to an engine start position, an FF10 is reset and at the same time an engine is actuated. When an alternator has a number of revolutions larger than the prescribed value, the rectifying voltage of a rectifier 7 is set at a level higher than the prescribed value in accordance with the AC voltage delivered from the alternator. Then a comparatro 9 sets the FF10, and a switch 11 is closed by the output of the FF10. At the same time, a large AC current is conducted to a degaussing coil 4 from the alternator. The coil 4 degausses a CRT display device. Then a positive characteristic thermistor 5 generates heat to increase the internal resistance of the thermistor 5. Therefore the AC current conducting to the coil 4 reduces. The FF10 is held in a degaussed state after once degaussed and never degaussed unnecessarily and repetitively. |
