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<p>[QUOTE=&quot;calcol, post: 2788599, member: 77639&quot;]Actually, doing it obverse to reverse ain&#039;t that simple to model.&nbsp; The probe tip contact area would be very small compared to the face area of the coin.&nbsp; There would curved lines (or shells) of current from probe tip to probe tip passing through the metal cylinder.&nbsp; Resistance is not measured directly but by application of a fixed voltage and measurement of current flow in the instrument (or in some cases, a fixed current is applied and voltage drop is measured).&nbsp; Try checking a 10 mA fuse with a handheld multimeter; even if it was good, it won&#039;t be after the probes are applied.</p><p><br /></p><p>Misalignment of the tips would cause variation in the measured resistance.&nbsp; Even if the tip apposition is perfect, variation in positioning of the tips relative to the axis of the cylinder would probably affect the measurement.&nbsp; I say &quot;probably&quot; based on intuition, but a mathematical proof might show otherwise.&nbsp; Then there is the fact that coins aren&#039;t perfect cylinders.&nbsp; Modern coins have&nbsp; excellent circularity (except for some error coins), but the thickness obverse to reverse can vary quite a bit at various points on the face (i.e. cylinder ends), depending on design elements, strike and wear.&nbsp; So where you place the probe tips on obverse and reverse would have a significant effect on micro-ohm (or nano-ohm or pico-ohm) measurements.</p><p><br /></p><p>Cal[/QUOTE]</p><p><br /></p>

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