| 摘要 |
Output amplifiers for driving picture tubes need to provide a high slew rate, and traditional class-A amplifiers have a high quiescent power consumption because of the high supply voltage combined with the necessary high quiescent current. According to the invention, the quiescent current is constituted mainly of the DC feedback current in the output device (TR3), and its control electrode is driven by means of a transistor (TR1), whose base has a reference potential, and whose emitter receives the static component of the control signal for the picture tube. In one embodiment the quiescent power consumption is 10-15 % of that of a corresponding class-A amplifier, and the required cooling means may be considerably reduced.
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