# circuit with 2 loops, find the current in one of the loops

by jenzao
Tags: circuit, current, loops
 P: 48 1. The problem statement, all variables and given/known data A circuit composed of one battery and four resistors is arranged as shown in the attached pic. E = 19 V R1 = 12 W R2 = 2 W R3 = 15 W R4 = 2 W Calculate the current I1 through R1? 2. Relevant equations V=IR (obviously) 3. The attempt at a solution first i got the net current in this circuit by doing the following.. i summed resistors in series to get 14ohm on first loop and 17ohm on second loop. then i applied resistance in parallel rule : Req = (1/R1) + (1/R2) = 7.69ohm = Rtotal then I = V/R = 2.47A = total current in the circuit. Then to get the current on the 14 ohm loopm i multiplied 2.47 by (14/17) . ( i think this is where I am erring, but cant see why this doesnt work??) = 2.03A (wrong) thanks for any help! 1. The problem statement, all variables and given/known data 2. Relevant equations 3. The attempt at a solution 1. The problem statement, all variables and given/known data 2. Relevant equations 3. The attempt at a solution Attached Thumbnails
 P: 48 sorry, pic pending approval --here it is uploaded to flickr... http://www.flickr.com/photos/31088870@N02/3560817988/
 P: 87 you're making this too complicated. the voltage between the two nodes must be the battery voltage. so if you know the voltage accross a resistor (or an Eq Res) you can find the current through it. use I = V/R, where R is the equivalent resistance of the branch and V is the voltage accross the branch.

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