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Re: Scoping of Secondaries
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To: tesla-at-grendel.objinc-dot-com
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Subject: Re: Scoping of Secondaries
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From: "Malcolm Watts" <MALCOLM-at-directorate.wnp.ac.nz>
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Date: Fri, 15 Dec 1995 12:11:28 +1200
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>Received: from rata.vuw.ac.nz (root-at-rata.vuw.ac.nz [130.195.2.11]) by uucp-1.csn-dot-net (8.6.12/8.6.12) with ESMTP id PAA19061 for <tesla-at-grendel.objinc-dot-com>; Thu, 14 Dec 1995 15:38:02 -0700
Glenn Baddeley writes...
> The base of the secondary is earthed via a low value
> resistor, and the CRO is strung across the resistor.
> The resistor value is a compromise between getting
> enough reading on the CRO and it not affecting the
> resonance very much. 100 Ohms or less seems about right.
My finding is that when it comes to high Q coils, 100 Ohms series R
is a VERY significant value compared to the AC resistance of the coil.
Earlier this year I measured the effects of various earth leads
of different types on the Q of a secondary coil. Even with a primary
secondary coupling reduced to less than 0.01, the nominal Q of the
coil was lowered by around 20%. I was still able to detect nominal
differences between the best wires and very large differences between
the best and worst.
Malcolm