HIGH-PRESSURE SODIUM DISCHARGE LAMP

摘要

The invention relates to 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 in parallel to the discharge vessel (3) with the transformer (35) electrically connected to the external auxiliary electrode (11). According to the invention, 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 lamp obtained starts very reliably with its built-in starter dissipating only a very low power.