| 摘要 |
1293890 Light modulators DEUTSCHE AKADEMIE DER WISSENSCHAFTEN ZU BERLIN 2 July 1971 31093/71 Heading H4F In a light modulator, a gas discharge lamp G is connected through a resistor R to a voltage source U 0 and via a diode D to a current source S. Ignition is controlled by a semi-conductor arrangement H, e.g. a plurality of series connected transistors with associated voltage dividers in turn controlled by duration or frequency modulated pulses. When a pulse is applied, the semi-conductor arrangement becomes conductive and the lamp is ignited by voltage source U o so that a current flows through the lamp from the source S which remains unchanged from one pulse to another. In a modification, the semiconductor arrangement is connected across the lamp so that current flows only when the semiconductor arrangement is blocked. In these arrangements a high resistance voltage source is used. If a low resistance voltage source is used, electronic switching to connect it to the lamp only for the duration of the ignition is required.
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