# Finding Current in a Parallel Circuit with Multiple Resistors

• Ry122
In summary: This can be generalized to any number of resistors in parallel: divide each resistance by the sum of all resistances, then multiply by the total current to get the current in that specific resistor.In summary, the conversation discusses finding the current passing through each resistor in a parallel circuit using the equation I=v/r and the ratios between each resistor. It is mentioned that this method can be used for any number of resistors in parallel by dividing each resistance by the sum of all resistances and multiplying by the total current.

## Homework Statement

Im aware that you can find the current passing through each resistor in a parallel circuit by using the equation I=v/r but for homework i was asked how to find the current by using the ratios between each resistor.
eg.
---5ohms---- Resistor 1
- 20ohm - Resistor 2
- 10ohms - Resistor 3
----| - |-----
I=20AMPS
If only resistor 1 and 2 exists i can do it by dividing 5 by 5+20 and dividing
20 by 2+20. Inverting the results so 5/25 is for resistor 2 and vice versa then multiplying the results by 20amps. This gives the amps passing through each resistor.
I've no idea how to do it if there is 3 or more resistors.

## The Attempt at a Solution

On the right track--we know that current is inversely proportional to resistance, so let's set up the eqn with a little i which is the current flowing thru the 20 ohm resistor: In fact, this makes use of the V=iR eqn at least implicitly, assuming 20 amps total passes thru the branch.

i+20/10*i+20/5*i=20A=7i. i=20/7, etc.

Now if 20 amps passes thru say the small resistor, and total current is unknown,

then (5/10)*20 will pass thru the 10 ohm and (5/20)*20 thru the 20 ohm.