- #1

oxon88

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## Homework Statement

A meter is shunted by a parallel resistance.

a) Determine the required value of the shunt resistance if the maximum value of the current I, is 200A. The meter can read a maximum of 1 mA and has a resistance of 0.1 Ω.

b) If the shunt is made of copper and has a cross-cectional area of 25cm

^{2}calculate its required length.

(for copper take ρ as 1.7x10

^{-8}Ωm

## Homework Equations

ohms law (V=I.R)

R = ρ.(l/A)

## The Attempt at a Solution

a)full scale voltage = 0.001 * 0.1 = 0.0001 v

shunt resistance R

_{shunt}= 0.0001/200 = 0.5x10

^{-6}Ω

R

_{shunt}= 0.5 mΩb)

0.5x10

^{-6}= (1.7x10

^{-8}) * ( l / 0.25

^{2})

(0.5x10

^{-6}/ 1.7x10

^{-8}) * 0.25

^{2}= ll = 1.83824 cm

does any of this look right? Thanks.