| 摘要 |
In a vertical deflection circuit, a deflection winding is coupled to an output terminal of a deflection amplifier. The amplifier generates a trace current in the winding in response to drive signals coupled to an input terminal of the amplifier. A first voltage source provides an operating voltage for the amplifier. A bidirectional retrace switch couples the output terminal to a second voltage source for providing a greater magnitude voltage for generating a retrace current in the winding. The bidirectional switch has a controlled semiconductor which is responsive to the drive signals for controlling a main conductive path of the switch during a portion of the retrace interval. A variable resistance device, such as a thermistor, coupled in the main conductive path of the switch, provides a low resistance during the retrace interval but provides a high resistance in the event the drive signals bias the controlled semiconductor element into the state for conduction through the main conductive path during a substantial portion of the trace interval.
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