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Author Topic: halogen lamp question  (Read 8997 times)

Offline sigurd

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halogen lamp question
« on: May 03, 2008, 12:36:40 pm »
Hi,

I have a couple of bulbs with the inscription "Osram BTP 750W 120V" and the total length is about 107 mm. When looking for a new bulb on the web I find that the total legnth is always stated as 127 mm. Does anyone know why this is so? The bulbs are for use in an old stereo projector, and I think 127 mm would be a bit too big for the projector chassis.

Thanks,
Sigurd

Offline briandancer

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Re: halogen lamp question
« Reply #1 on: July 22, 2008, 03:16:35 pm »
As to why this change occurred, it is likely the result of the lighting industry slowly, over time, merging photo bulbs into a smaller number of replacements.  Since photo bulbs are far less common today than they were 30 years ago (exhibit A = price), and they sell far fewer of them, it makes sense (to them) to squish 1000 different bulbs into 200 or so "compatible" varieties. 

It goes back to the fact that it's cheaper to offer 200 varieties than 1000 of them.  Now, in it's heyday, the sales of these bulbs justified the cost of producing wider varieties, that's just not the case anymore.

Brian Dancer
Service Lighting