Tungsten Halogen - Double Ended

The original and oldest category of halogen lamps is the Double-Ended design, in which a quartz tube is sealed at both ends around a tungsten filament. The linear filament has optical advantageous for certain applications, but the length of these lamps is not always convenient from the mechanical and optical point of view. Also in terms of cost, two seals have to be made, and two lampholders are required. For this reason the original double ended halogen lamps on this page have, in many applications, gradually been superseded by the more compact and lower cost Single-Ended halogen lamps.

In a few cases however, the double-ended design continues to offer advantages over single ended lamps. For high power floodlighting the small diameter and linear filament design is optically preferable. Additionally, double ended capsules are frequently embodied within other lamp envelopes. For instance in the case of high-efficacy lamps having infra-red reflective coatings, it is found that the double-ended design allows greater precision in focussing the filament at the optimum position.



Linear Halogen K/9 with Fuse Chambers



2⅝" Type FAL (A1/227) First Halogen for O.H.P.