| 摘要 |
PURPOSE:To realize automatic magnetic erasure by turning on the gate of a thyristor through a capacitor charged with a main switch in a color TV receiver, and then flowing the charging current of another capacitor to a magnetic erasing coil. CONSTITUTION:When the main switch (not shown in the figure) of equipment is turned on, the charging of a capacitor 10 up to a DC voltage 120V is started through a resistance 9. A DC power source 20V, on the other hand, starts charging a capacitor 14 and when the charged voltage of a Zener diode 15 exceeds its threshold value, a transistor (TR) 17 turns on. Consequently, a TR22 turns off and its collector potential rises to flow a current through the gate of a thyristor 12, which turns on to flow charges, stored in the capacitor 10, to the ground through a magnetic erasing coil 1, thus performing the magnetic erasure by a damping oscillation current. |
