Re: OT: They don't make 'em like they used to

Athol wrote:
>
>The tungsten filaments tend to melt very rapidly (sometimes to the point
>of va****ising well enough to deposit the vapour on the inside of the
glass
>of the globe as they fail.  That happens due to the thermal shock of the
>sudden heating that occurs when it's turned on, combined with the lower
>resistance when cold (positive temperature coefficient) as John
mentioned.

Long before Vance Packard (The Waste Makers) alerted the World to
planned obsolescence, light globes were seen my many as an example of
just that.  I can remember being told as a kid that light bulbs didn't
last like they used to because the manufacturers deliberately
introduced a whiff of oxygen to ensure their premature demise.

All bull**** of course, but it no doubt came from the observations of
those who remembered carbon filaments.  Not sure, but I'd guess they
were last manufactured sometime prior to WW1....  All the ones I've
ever seen had Edison Screw bases which suggests they also pre-dated
the bayonet fitting which was very likely introduced at the same time
as tungsten filaments.

-- 
John H