Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!gem.mps.ohio-state.edu!usc!snorkelwacker!mit-eddie!uw-beaver!uw-entropy!dataio!pilchuck!seahcx!phred!brianr
From: brianr@phred.UUCP (Brian Reese)
Newsgroups: sci.electronics
Subject: Re: 7805 woes
Message-ID: <2842@phred.UUCP>
Date: 10 Nov 89 01:49:53 GMT
References: <12236@fluke.COM> <1989Nov7.233936.24863@ux1.cso.uiuc.edu>
Reply-To: brianr@phred.UUCP (Brian Reese)
Organization: <1989Nov7.233936.24863@ux1.cso.uiuc.edu>o
Lines: 33

In article <1989Nov7.233936.24863@ux1.cso.uiuc.edu> kline@tuna.cso.uiuc.edu (Charley Kline) writes:
:>I've been slapping together 5v power supplies for years with a fair amount
:>of success using the following. Anyone see any room for improvement without
:>driving up the cost? Yes I know I can use a 723 and 2N3055 power transistors
:>and do better, but that also would about double the cost of this.
:>
:>			                 7805
:>                  +-----+             +-------+
:><-----B|B---------|ac  +|---+---------|in  out|-------+------> +5
:>      B|B         |     |   |         |  gnd  |       |
:>120AC B|B T1      | B1  |   =C1       +-------+       =C2
:>      B|B         |     |   |             |           |
:><-----B|B---------|ac  -|---+-------------+-----------+------> gnd
:>                  +-----+
:>
:>
:>T1 -   6.3v, 1.2A secondary power transformer.
:>B1 -   1.5A 100v bridge rectifier.
:>C1 -   2000uFd 16V electolytic
:>C2 -   47uFd 16V electolytic

Looks like a good GP supply.  The only parts I would add to this would be
a reverse biased diode from the output to ground, and another from the
input to the output.  Well, maybe a 0.1uF ceramic in parallel with C1 too.

Brian


-- 
Brian Reese                           uw-beaver!pilchuck!seahcx!phred!brianr
Physio Control Corp., Redmond, Wa.                         brianr@phred.UUCP
"Sticks and stones may break my bones, but whips and chains excite me!"
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