Shield Coverage and Resistance

Shield Coverage:

The following equation can be used to determine the percent coverage of a braided or spiral shield:


Braid Shield \[Tan(a) = \frac{{2\pi (D + 2d)P}}{C}\]
Spiral Shield\[Tan(a) = \frac{{\pi P(D + d)}}{C}\]


D is diameter under shield (inches)

d is diameter of strand, inches (Typically #30 AWG Solid to #40 AWG Solid)

P is picks per inch

N is number of strands per carrier (typically integer values of 1 to 13)

a is shield angle, degrees

% is percent coverage (must be less than 100%)


\[\% = (2F - {F^2})*100\] \[\% = 100*F\]

for Braid Shields

for Spiral Shields


\[F = \frac{{NPd}}{{\sin (a)}}\]

Shield Resistance:

The D.C. resistance for braided shields can be calculated using the following equation:

\[R = \frac{r}{{NC\cos (a)}}\]


R is D.C. resistance, (ohms/m1) for the braided shield construction

r is D.C. resistance of 1 strand (ohms/m1)

a is braid angle, degrees

N is number of strands per carrier

C is number of carriers

Read 12665 times Last modified on Wednesday, 01 January 2014 21:24

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