# Thread: Solve for the current in each branch of the circuit...

1. ## Solve for the current in each branch of the circuit...

Solve for the current in each branch of the circuit shown below.

Note:

E1= 10 V
R1= 10 (Omega)
E2= 20 V
E3= 30 V
R2= 20 (Omega)
R3= 30 (Omega)

Here's a (poorly drawn) diagram: http://i449.photobucket.com/albums/q...r/untitled.jpg

Any help would be greatly appreciated.

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Would you go V= IR?

Or take 1 over the resistor values and add them together?

2. If you add the currents flowing into node A, they have to sum to zero:

$\displaystyle I_1+I_2+I_3=0$

Let $\displaystyle E_A$ be the voltage at A. Then use I=E/R to calculate each of the currents:

$\displaystyle \frac{30-E_A}{30}+\frac{20-E_A}{20}+\frac{10-E_A}{10}=0$

$\displaystyle 1-\frac{E_A}{30}+1-\frac{E_A}{20}+1-\frac{E_A}{10}=0$

$\displaystyle 3=\left(\frac{1}{30}+\frac{1}{20}+\frac{1}{10}\rig ht)E_A$

and now that you have $\displaystyle E_A$, you can use I=E/R to calculate each of the currents.

Post again if you're still having trouble.