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From: "Phil Allison"
References: <firstname.lastname@example.org> <email@example.com> <3DEB8034.firstname.lastname@example.org> <email@example.com> <3DECCCDF.firstname.lastname@example.org> <3DED7F7E.email@example.com>
Subject: Re: Triac controlled holiday lights
X-Newsreader: Microsoft Outlook Express 5.50.4522.1200
Date: Wed, 4 Dec 2002 15:16:37 +1100
NNTP-Posting-Date: Wed, 04 Dec 2002 15:05:38 EST
Organization: Telstra BigPond Internet Services (http://www.bigpond.com)
"Fred Bloggs" wrote in message
> Phil Allison wrote:
> > "Fred Bloggs" wrote in message
> > news:3DECCCDF.firstname.lastname@example.org...
> >>Right- but those were for bulbs rated for 120VAC. The half-wave
> >>rectification cuts the RMS down to 70% of that or 84VAC. In your case,
> >>you would have 84VAC across a string rated for 60VAC, and this will be
> >>bad news. My dimensions were off in the original post, but if the bulbs
> >>are rated at 700 hours on 60VAC, then 84VAC will reduce their lifetime
> >>to 12 hours.
> > ** No, much less than that with a 40% overvoltage.
> > The 2 to the power of 12 rule is only valid for small voltage
> > deviations.
> > You must have missed that one at Uni Fred.
> It is not a 2^12 rule, it is the (voltage ratio)^12 rule, and in this
> instance it is good for concluding with great confidence that 84Vrms is
> way out of bounds.
** Then you should have posted *that* and not the erroneous figure you
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