> From cobra@cdc.hp.com Mon Jun 13 16:35:03 1994
> From: Roland Dudley <cobra@cdc.hp.com>
> Subject: Re: Light bulbs and heat
> To: Simon.Matthews@tiuk.ti.com
> Date: Mon, 13 Jun 94 8:36:48 PDT
> Cc: british-cars@autox.team.net (XXX)
> Mailer: Elm [revision: 70.85]
> Content-Length: 684
>
>
> > I don't like to be pickey about this, but there should be less heat, not
>more.
> > If the bulbs are rated at the same wattage (ie. energy input) and a greater
> > proportion of that energy is emitted as visible light (ie. they are
>brighter),
> > then it follows that a smaller proportion must be emitted as heat.
> >
> > Simple really!
> >
> > Simon Matthews
> >
>
> Simon,
>
> As a EE you're argument seems reasonable to me, but I never claimed that
> the bulbs were rated at the same wattage and it's the bulb's
> manufacturer, not me, that claims they get hotter. Then there is the
> empirical evidence: they DO get hotter.
>
> Didn't we have this same discussion on the list a few months back?
>
> Roland
>
We have to differentiate between the total heat emitted and that absorbed by the
envelope (quartz or glass).
I thought that the discussion was about heat in the light unit, not temperature
of the bulb. Feel free to correct me if I am wrong about this!
I do believe that halogen bulbs run hotter -- but, I suspect that it may be
because the quartz enevelope is smaller and thus it is poorer at distributing
heat via convection.
Regards,
Simon (BSc in Physics with Electronics, and former employee of Lucas!) Matthews
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