# Application of Circuit laws (KCL and KVL)

1. Jan 16, 2013

### hms.tech

1. The problem statement, all variables and given/known data
Calculate the resistance of this combination of resistors

2. Relevant equations

V=IR

3. The attempt at a solution

By using KVL :

V= 3$I_{5}$ = $I_{2}$ = 2$I_{4}$
I = $I_{1}$ + $I_{2}$
$I_{3}$ = $I_{2}$ + $I_{4}$
$I_{1}$ = $I_{5}$ + $I_{4}$
I = $I_{3}$ + $I_{5}$

Now the final result could be obtained by the simple equation : R =V/I (this is where my progress stagnates)

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2. Jan 16, 2013

### Staff: Mentor

Your first equation relates currents I2, I4, and I5 to the potential across the circuit. Now, if you take your last equation and make substitutions so that you express I in terms of those same currents in the first expression, I think you'll get somewhere.

3. Jan 16, 2013

### hms.tech

You mean like this :

I = $I_{5}$ + $I_{2}$ + $I_{4}$

Thus R = V/I

that does not solve the problem ...

4. Jan 16, 2013

### Staff: Mentor

But you can substitute your expressions for those currents from your first equation...

5. Jan 16, 2013

### hms.tech

Oh yes, I overlooked this .
Thanks you