Demagnetizing circuit and current limiting device

摘要

A demagnetizing circuit and a current limiting device for being built into a power supply circuit of a color television receiver or color monitor display or the like with which it is possible to effect a reliable demagnetizing operation using existing components and without using either a positive characteristic thermistor which reaches a high temperature or a relay circuit. The demagnetizing circuit is connected in parallel with a power supply circuit having a smoothing capacitor and a negative temperature characteristic thermistor or fixed resistance for suppressing surge currents to the smoothing capacitor. It has a thermally actuated switch connected in series with one end of a demagnetizing coil by way of a positive temperature characteristic thermistor which is actuated by heat produced by the temperature negative characteristic thermistor or fixed resistance to cut off a demagnetizing current. The current limiting device within the demagnetizing circuit includes the negative temperature characteristic thermistor or fixed resistance, the positive temperature characteristic thermistor and the thermally actuated switch interposed between the negative temperature characteristic thermistor or fixed resistance and the positive temperature characteristic thermistor. The thermally actuated switch has a thermally actuated member which is caused to bend by heat produced by the negative characteristic temperature thermistor or fixed resistor, and a moving contact point and a fixed contact point which are opened by this bending of the thermally actuated member.