| 摘要 |
PURPOSE:To prevent a load connected to a horizontal output circuit from damaging by controlling a horizontal oscillation circuit so that an oscillation frequency will be increased as the detected current of the horizontal output circuit increases. CONSTITUTION:As a current at terminal 7 increases, a potential at terminal 8 to the earth falls. When it exceeds a fixed value, constant-voltage diode 11 conducts to decrease the base potential of transistor 2 while increasing the oscillation frequency of horizontal oscillation circuit 1, and consequently horizontal output transis- tor 16 is also driven at a high frequency. The flyback time of a horizontal output circuit depends upon the inductance of deflecting coil 19 and the capacity of resonance capacitor 18 without reference to a horizontal oscillation frequency. Therefore, the sweep time is shortened as the horizontal oscillation frequency increases. In addition, since a DC power circuit supplies a current to the horizontal output circuit only in the sweep time, the sweep time is reduced to approximate 40% when the oscillation frequency is doubled, and consequently the impedance increase approximately twice and a half, limiting power supplied from the DC power circuit. |
