Color TV automatic degaussing circuit schematic

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Many iron parts inside and outside the color picture tube are often magnetized during use to generate stray magnetic fields (the magnetic field is a special material that is invisible and invisible, and it has the radiation characteristics of the wave particles. There is a magnetic field around the magnet. The interaction between the magnets is based on the magnetic field. Since the magnetism of the magnet is derived from the current, the current is the motion of the charge, and in general, the magnetic field is generated by the change of the moving charge or electric field, which affects the electron. The normal deflection of the beam causes damage to color purity and convergence, directly compromising the quality of the image. Therefore, modern color televisions are equipped with automatic degaussing circuits. The function of the automatic degaussing circuit is to degauss the picture tube and surrounding components automatically every time it is turned on. A degaussing circuit is composed of a degaussing coil L string and a positive temperature coefficient thermistor RH, which is connected in front of the power rectifier bridge. The degaussing coil is installed near the safety explosion-proof hoop of the cone portion of the picture tube, and the thermistor has a resistance value of about 20 Ω at normal temperature. When starting up, there is a large current of 1A or more flowing through the L and RH series branches, which produces a strong alternating magnetic field. The thermistor generates heat due to power consumption, causing the resistance to increase sharply, causing the current to decay rapidly, and the corresponding alternating magnetic field is also weakened. Finally, the equilibrium state is reached, and the high resistance of the thermistor maintains a minimum current, which in turn causes the thermistor to maintain a minimum current, which in turn maintains the thermistor at a relatively high temperature and is stably high. Resistance state. The magnetic field generated by this minimum holding current is weak enough to no longer affect the normal scanning deflection of the electron beam. In the above process, the residual magnetism of the picture tube and surrounding components is eliminated by the strongly weakened alternating magnetic field.

Color TV automatic degaussing circuit diagram