(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

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

2. Relevant equations

ohms law (V=I.R)

R = ρ.(l/A)

3. 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 mΩ

b)

0.5x10^{-6}= (1.7x10^{-8}) * ( l / 0.25^{2})

(0.5x10^{-6}/ 1.7x10^{-8}) * 0.25^{2}= l

l = 1.83824 cm

does any of this look right? Thanks.

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Electrical dc shunt resistace question

**Physics Forums | Science Articles, Homework Help, Discussion**