online calculator or formula applicable to gauge less than 50 SWG ?

I presume that the sizing conventions still hold, where the gauge value is logarithmically related to the nominal resistance. 50 gauge should be about 10 ohms/foot, 60 about 100 ohms/foot, etc.

19.7/meter is about 6 ohms/foot, so that should be about 48 gauge?

There is a free downloadable calculator that goes to 60 gauge (and that has other capabilities as well) over at

--
Rich Webb     Norfolk, VA

As a last resort, you could try drawing a graph of diameter or diameter-squared against SWG, AWG or resistance. If you can find a straight-line relationship, you can extrapolate to any value you need.

I think you can still buy graph paper, rulers and pencils in shops - if you can find any shops. :-)

--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

On Mon, 15 Aug 2011 15:12:37 +0100, "N_Cook" put finger to keyboard and composed:

Resistivity is calculated according to the following formula:

rho = R x A / L

where ...

rho = resistivity = 1.68e-8 ohms/metre for copper R = resistance A = cross-sectional area L = length of material

Therefore ...

A = rho / (R/L) = 1.68e-8 / 19.7

A = pi x r^2 = pi x (dia/2)^2

dia = 2 x sqrt(A / pi) = 2 x sqrt(1.68 x 10^-8 / 19.7 / pi) = 0.03295 mm

(1.68+x+10%5E-8+/+19.7+/+pi)

According to the tables, your wire size appears to be 49 SWG.

- Franc Zabkar

--
Please remove one 'i' from my address when replying by email.

"Nutcase Kook"

** Last time I dealt with fine enamelled wire like, that it was from the high impedance (output end ) transducer of an Accutronics reverb unit.

But the finest I have seen is on the coil of an AKG D19 ( 200 ohms) mic capsule - about 0.03 mm.

The D19 diaphragm was sold as a spare part and used in other mics, like the original D12.

..... Phil

copper

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Thanks for that, a useful little suite of apps