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From: "Shaun Davy"
Subject: Re: High Voltage Input into 78xx
X-Newsreader: Microsoft Outlook Express 6.00.2800.1106
Date: Thu, 31 Oct 2002 21:15:18 +1100
NNTP-Posting-Date: Thu, 31 Oct 2002 21:22:12 EST
Organization: Telstra BigPond Internet Services (http://www.bigpond.com)
Sorry, forgot to add that i have no problems using any other regulator, i
don't have to use the 7805.
"Shaun Davy" wrote in message
> Basically the circuit runs off an input (upto 24VAC) that is switched on
> off with triacs. The input also runs the circuit which requires +5V DC to
> switch on and off the triacs.
> Sorry i didn't really think about the fact the 1A needs to dissipate 30W!!
> Basically it needs to be around the 250mA mark but realistically up to .5A
> would be good for anything in future. 1A would be good to know if possible
> but really needed.
> The main suggestions so far seem to be use a switching regulator.
> Would this be the simplest and most effective way? if so is there a
> switching regulator that is fairly common, i guess the switching
> of the 78xx series?
> Thanks again
> "Shaun Davy" wrote in message
> > Just wondering if anyone could point me in the direction of how i could
> > about running a +5V regulator off a 35V DC input (24VAC) and draw around
> > 250mA mark and if possable for future projects upto .5A or 1A.
> > Should i just use a normal 7805 and strap a big heatsink to it to
> > all that heat or is there a better more efficient way?
> > Thanks
> > Shaun
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