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Hello,<br><br>
The small caps are usually used to prevent the crystal from oscillating
in the overtone<br>
mode and are usually in the 10's of pF range (value depends on crystal
characteristics).<br><br>
0.1uF just shorted out even the crystal's fundamental to GND and so no
oscillation.<br><br>
Hope this helps. Jeff<br><br>
<br>
At 11:58 PM 10/20/03 -0700, David Shoemaker wrote:<br>
<blockquote type=cite class=cite cite><font face="arial" size=2>DOH,
those of you on the vector list will have already seen this. Sent
it to the wrong list.</font><br>
<br>
<font face="arial" size=2>For those of you not on
vectorlist:</font><br>
<br>
<br>
<br>
<font face="arial" size=2>While building up the two beta 9100 keyboard
wedge boards I realized I didn't have any 22pf caps. So I tossed a
pair of 100pf caps onto my breadboard of the circuit and everything
worked great.</font><br>
<br>
<font face="arial" size=2>Then I went to build the perfboard version and
realized I only had two of the 100pf caps and as I wanted to leave the
breadboard version intact for now so I grabbed a pair of .1uf
caps.</font><br>
<br>
<font face="arial" size=2>Hooked everything up and it didn't
work.</font><br>
<br>
<font face="arial" size=2>So I checked everything twice more and still no
go. Got to wondering if maybe the value of those caps is really
important and realized I have NO idea how to spec them nor even what they
do.</font><br>
<br>
<font face="arial" size=2>So can anyone enlighten me?</font><br>
<br>
<font face="arial" size=2>I have seen circuits use 18pf, 22pf and 27pf
for the crystal caps. The 100pfs do work, but I wonder now if I
just got lucky.</font><br>
<br>
<font face="arial" size=2>Also which should I use, simple ceramic disc or
the Monolithic ceramic disc?</font><br>
<br>
<font face="arial" size=2>David</font></blockquote></html>
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Received on Tue Oct 21 09:48:20 2003
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