Bulb glass envelope size

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hokiefyd

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The GE bulbs in HB2 have a much larger (physically) glass envelope than Philips or Sylvania/OSRAM bulbs. It made me curious: does the volume of the envelope effect any behavior of the bulb?
 

Alaric Darconville

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The GE bulbs in HB2 have a much larger (physically) glass envelope than Philips or Sylvania/OSRAM bulbs. It made me curious: does the volume of the envelope effect any behavior of the bulb?

Usually, the smaller the envelope, the more quickly the filament heats up and the more effective the halogen cycle is. Is the envelope *longer*, or just wider, or both on these?

One thing that could account for it being larger is that the filament supports may be shaped differently to reduce shadows and reflections from them, but this is just conjecture.
 

hokiefyd

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I'm pretty sure the envelope is the same length (or very close), but the GE envelopes do have a larger diameter, so their volume appears to be greater. The same is true of the standard GE lamps in a store, so I'm wondering if it has to do with their manufacturing process.
 

-Virgil-

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The filament heats up immediately regardless of the capsule diameter. The smaller the capsule, the faster the capsule reaches the critical temperature threshold for the halogen cycle to begin. But that doesn't necessarily mean a bulb with a small capsule is better than one with a large capsule.
 
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