It is known to start high-pressure metal vapor discharge lamps such as sodium or halogen metal vapor high-pressure discharge lamps by applying a starting pulse thereto, obtained upon discharge of a starting capacitor. The starting capacitor is serially connected with a damping resistor. The circuits are suitable to start cold discharge lamps as well as to re-start or re-ignite already warm high-pressure metal vapor discharge lamps. The starter or igniter circuit is connected as a series circuit by a manually operated switch or by a relay contact connected to the auxiliary apparatus for starting the lamp.
Starter or igniter circuits of this type are expensive and require much material; they are sensitive to temperature changes and, particularly the current carrying terminals, are subject to malfunction.
After a lamp has started, further starter or ignition pulses should be suppressed; in superimposed starting circuits, it has been proposed to use semiconductor circuitry to suppresss further starting pulses. Yet, these circuits heretofore did not operate with sufficient reliability, that is, starting was then not insured. Some lamps are difficult to start, and particularly with such lamps, starting reliability was subject to improvement.
USPTO Backgrounds
USPTO Backgrounds