\[ {\varepsilon _1} = x{l_1}\]
Where :
\[ \frac{{{\varepsilon _1}}}{{{\varepsilon _2}}} = \frac{{{l_1}}}{{{l_2}}}\]
Where :
\[I = \frac{{x{l_1}}}{{{R_1}}}\]
Where :
\[ {\varepsilon _1} = \left[ {\frac{{{l_1} - {l_2}}}{{{l_2}}}} \right]R\]
Where :