| 摘要 |
PURPOSE:To bring residual currents to zero, and to improve switching characteristics by contact-bonding and fixing a positive temperature coefficient thermistor, both surfaces of which have electrodes, between plate-shaped first and second terminals, fastening a bimetal to the second terminal abutting on the positive temperature coefficient thermistor and mounting a third terminal so that one end of the bimetal is brought into contact and short-circuited by thermal deformation when the temperature of the thermistor rises. CONSTITUTION:When a switch SW is closed and a positive temperature coefficient thermistor 10 is conducted, large alternating currents flow and heat is generated because the resistance value of the positive temperature coefficient thermistor 10 is small at first, and the resistance value suddenly rises when the temperature of the thermistor 10 reaches a Curie temperature. Since alternating currents are reduced gradually with the sudden rise of the resistance value, a large alternating field applied first slowly damps in a demagnetizing coil 19, and a magnetic field magnetized to the peripheral section of a shadow mask for a CRT is erased. Heat by the heat generation of the thermistor 10 is transmitted over a bimetal 15 through a terminal 13 at the same time, and the bimetal is thermally deformed, and brought into contact and short-circuited with a terminal 14. Accordingly, damping alternating currents are bypassed between the terminal 13 and the terminal 14, and no magnetic field is generated in the coil 19, thus removing the color shading of the peripheral section of the shadow mask.
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