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From: straka@cbnewsc.ATT.COM (richard.j.straka)
Newsgroups: sci.electronics
Subject: Re: Sources for 7-volt regulators
Keywords: Parts, sources
Message-ID: <14540@cbnewsc.ATT.COM>
Date: 21 Mar 90 04:27:16 GMT
References: <5598@oolong.la.locus.com>
Reply-To: straka@cbnewsc.ATT.COM (richard.j.straka,ih,)
Organization: AT&T Bell Laboratories
Lines: 19

In article <5598@oolong.la.locus.com> dana@locus.com (Dana H. Myers) writes:
>In article <844@gold.GVG.TEK.COM> grege@gold.GVG.TEK.COM (Gregory Ebert) writes:
>>You can 'fool' a 78L05 into working as a "78L07" by putting 3 1N4148
>>(or your favorite Si diode) in series with the ground terminal of the
>>regulator. Basically , the regulator only cares that the "out" terminal
>>is 5 volts above the "gnd" terminal. The 3 diodes will give about 2.1
>>volts drop, thus Vout = 5.0 + 2.1 = 7.1 volts ~ 7.0 volts. Be sure to

I thoought that the commonly accepted way of doing this was to simply put
the ground terminal of the regulator at the middle of a 2-resistor divider
between the output and ground.  The extra current coming out of the ground, as
I recall, is either quite repeatable, or negligible.  Anyway, the divider
circuit is found all over the place in the old National Semi data books.  At
worst, it would be a little trial and error with the resistor values.
-- 
Richard Straka                  AT&T Bell Laboratories, IH-6K311
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