I'm doing the exercises from Wisc-Online. This one
I think they are really great to learn and practice and have already done a bunch of their practical trainings. But here I'm starting to be crazy. I need to calculate \$I_{r1}\$
Here's the schema :
simulate this circuit – Schematic created using CircuitLab
According to their lesson :
\$I_{Rx} = \dfrac{R_{T}}{R_{x}} \times I_{T}\$
So :
\$I_{R1} = \dfrac{R_{1} \parallel R_{2}}{R_{1}} \times I_{T}\$
With values :
\$I_{R1} = \dfrac{\dfrac{1}{\cfrac{1}{5000}+\cfrac{1}{10000}}}{\dfrac{1}{5000}} \times 3mA\$
\$I_{R1} = 50000mA\$
But the answer should be 2mA
What's wrong in my formula ? :'(
Best Answer
Sorry... I just figured out what was wrong... It's not :
\$I_{R1} = \dfrac{\dfrac{1}{\cfrac{1}{5000}+\cfrac{1}{10000}}}{\dfrac{1}{5000}} \times 3mA\$
But :
\$I_{R1} = \dfrac{\dfrac{1}{\cfrac{1}{5000}+\cfrac{1}{10000}}}{5000} \times 3mA\$
And in that case I've got the correct answer.
Sorry.