[HBR] Voltage rating for mica padding capacitors?

[David Richards]

If anything, Q should be higher. Less L (& therefore, less series resistance) & more C.
Coupling could be under-critical however, yielding significantly lower gain than a normally constructed transformer.

--- On Mon, 7/12/10, Walt Hutchens <waltah at earthlink.net> wrote:

From: Walt Hutchens <waltah at earthlink.net>
Subject: Re: [HBR] Voltage rating for mica padding capacitors?
To: hbr at mailman.qth.net
Date: Monday, July 12, 2010, 7:00 PM

> So I take it is OK to use a 200 VDC rated mica cap across the coils.
> Is this corrrect?

You're absolutely right: 200 VDC rating is AMPLE when placed across
the coils.

One issue that isn't often mentioned with this pad-them-down-to-100kcs
approach is that the Q will be less than for transformers designed for
the desired frequency. It's hard to guess the exact reduction, but
'significant.' 3-6 db per coil, maybe.

HOWEVER, the HBR-series sets have more than ample gain, so this
shouldn't be a problem.  It would be measurable as a slightly
increased bandwidth (since the 100 kcs xfmrs govern that) but probably
not really an issue.

Walt
KJ4KV




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