Electrode with overwind for miniature metal vapor lamp

摘要

An electrode for a miniature high pressure metal vapor lamp comprises a slender tungsten shank joined to a molybdenum inlead by a weld knot. The shank diameter is chosen above the size where melt-back starts at the intended lamp current and is provided wth a fine wire overwind fitting loosely thereon and retained in place by frictional engagement with the weld knot. The overwind reduces breakdown voltage and assures rapid glow-to-arc transition.