U.S. Philips Corporation

North American Philips Corporation

Cornelis A Jacobs

Hubertus M Chermin

A high intensity discharge lamp having a plurality of discharge device, and a starting aid for preferentially starting one of the discharge devices. Upon initial application of power to the lamp the preferentially started discharge device will start first, and the other discharge devices will not start. A power interruption during lamp operation will cause an interruption in the operation of the discharge device started first, upon reapplication of lamp power one of the other discharge devices that had not been operating will start without a hot restart delay.

Multiple discharge device hid lamp with preferential starting

A high-pressure sodium discharge lamp comprising a discharge vessel (3) provided with an external auxiliary electrode (11) and a built-in electric starting circuit including an electric circuit comprising a transformer winding (35a), a capacitor (33) and a semiconductor switching element (34). The circuit is connected in series with a resistor (32) electrically parallel to the discharge vessel (3) and with the transformer (35) electrically connected to the external auxiliary electrode (11). The semiconductor switching element (34) is an uncontrolled voltage-dependent breakdown element of the thyristor type having a breakdown current smaller than 1 mA at a breakdown time shorter than 10 .mu.s. The resultant lamp starts very reliably and its build-in starter dissipates only a very low power.

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Bath, NY, United States of America

Cornelis A Jacobs