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Old 11th March 2004, 11:10 PM   #1
RKH is offline RKH  United States
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Location: Colorado, USA
Default Zen V4 C3 Value?

Check twice, solder once...

The schematic and parts list in the Zen V4 article list C3 as 0.001 uf. Whilst the Digikey part number p4773-nd is 0.0001 uf. Sure enough, that's what is says on the package containing the ones I ordered

Which value is correct?

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Old 12th March 2004, 06:23 PM   #2
RKH is offline RKH  United States
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Default one more time

I'm going to bump this up one more time to see if I can draw some attention. From another parts list posted elsewhere, it appears that 0.001 uf is the correct value.
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Old 12th March 2004, 07:10 PM   #3
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The explanation for C3's purpose etc. is explained in the Zen Variations Part 2 article, which states:

"When Q3 begins to conduct, it limits the Gate voltage of
Q2, and this forms a little feedback mechanism which
limits the voltage across R1 at about .66 volts. R6, R7,
and C3 are there to help make this arrangement stable
and reliable, and we could possibly omit these, but we

In ZV4 the part references are the same with the exception of R1 in ZV2 is now R0 in parallel with R1 in ZV4. The value of 0.001uF is correct.

Essentially, C3 is not critical and you can leave it out if you like, or you can use the 0.0001uF capacitor as well.

Can't say I'm an expert at this, and others can correct me if I'm wrong, but since nobody else was replying ....

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Old 12th March 2004, 08:17 PM   #4
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The two possible uses are CE on the NPN, which tends to
be .01 uF, and CB, which tends to .001. These values aren't
critical and can often be omitted (until you find the output stage
exhibiting some oscillation, which it may or may not.)
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