摘要 |
A method of establishing coil dimensional stability by thermally stress relieving the tungsten filament prior to mounting in a lamp. The filament is manipulated into the desired position by coiling it first around a primary mandrel, then a retractable secondary mandrel. After the secondary mandrel is removed, the filament is held in place by a pair of electrical contacts. A current is passed through the primary coil, which heats the tungsten and causes it to recrystallize. The recrystallization provides the desired dimensional stability.
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