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<DIV dir=ltr align=left><SPAN class=579083307-10122018><FONT color=#0000ff
size=2 face=Arial>Such a "zener bridge" is at the heart of every Dixie, Rubicon,
and Atlantis VCO.</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=579083307-10122018><FONT color=#0000ff
size=2 face=Arial></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=579083307-10122018><FONT color=#0000ff
size=2 face=Arial>The idea is that the zener bridge gives more symmetrical
results than two back-to-back zeners. However, it relies upon
the assumption that the two pairs of regular diodes are identical.
This is probably more true than assuming that any two zeners of the same nominal
voltage are identical, but it is still an assumption.</FONT></SPAN></DIV><BR>
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<DIV dir=ltr lang=en-us class=OutlookMessageHeader align=left>On Wed, 28 Nov
2018 at 10:18, Steve Lenham <<A
href="mailto:steve@bendentech.co.uk">steve@bendentech.co.uk</A>>
wrote:<BR></DIV>
<DIV>
<DIV>
<DIV>
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<DIV class=gmail_quote>
<BLOCKQUOTE
style="BORDER-LEFT: rgb(204,204,204) 1px solid; MARGIN: 0px 0px 0px 0.8ex; PADDING-LEFT: 1ex"
class=gmail_quote>...<BR>If, however, it is only bipolar symmetry that you
are after rather than <BR>an exact level, consider putting a single Zener
inside a diode bridge. <BR>That makes the positive and negative clip levels
identical.</BLOCKQUOTE>
<DIV><BR></DIV>
<DIV>Sorry to be late on this ball, but I remember seeing (and saving) a
schematic example of this, a single zener surrounded by 2 or 4 diodes in some
bridge configuration - but now I cannot find it. The main point of it as I
remember was to get a very symmetric output by avoiding having more than one
zeners (since they are rarely as well matched as regular diodes), and instead
use the same zener as the level reference for both the positive and the
negative side. I guess a TL431 could give an even better result.</DIV>
<DIV><BR></DIV>
<DIV>Can anybody give a pointer to where this has been described?</DIV>
<DIV><BR></DIV>
<DIV>Thanks :-)</DIV>
<DIV><BR></DIV>
<DIV>/mr</DIV></DIV></DIV></DIV></DIV></DIV></BLOCKQUOTE></BODY></HTML>