| 摘要 |
<p>PHB. 32,692 15 A series regulated power supply arrangement for an image intensifer tube, comprising an oscillator circuit, a high voltage multiplier and an automatic brightness control (ABC) circuit. The ABC circuit includes a series regulator for producing a variable voltage to be supplied to the microchannel plate of the image intensifier tubethe series regulator comprises a junction power transistor having a load resistor connected to its collector. The junction of the collector and the load resistor is connected to the output terminal and the other end of the resistor is connected to a fixed, high voltage rail derived from the oscillator circuit. A feedback amplifier is connected to the base of the transistor and one input of the amplifier is coupled to a tapping of a potential divider coupled between one output terminal (CPI) and ground. The transistor is an off-the-shelf power transistor which is operated in class A with a current gain less than unity and at such a low maximum collector current that the risk of thermal runaway which would lead to second breakdown avoided.</p> |
