Discussion in 'Homework Help' started by stinky111, Apr 30, 2011.

1. ### stinky111 Thread Starter Member

Apr 7, 2011
39
1
Hi all,

IF R1=13Ω, R2=42Ω R3=???Ω.

V=230Volts & I=53amps.

Calculate R3

Im familiar with using Volts & Amps to get Resistance Total, but not sure with above when given 2 of the 3 resistance values.

Using V & I to calculate I get:

Rt = 4.339622Ω

I thought it would make sense(in my head to) then -R1 & R2 values from Rt to give R3??
Is this correct?? Thx

Apr 5, 2008
15,806
2,389
Hello,

You can take an other approach to the problem.
You know the total current.
You know two resistor values.
With the given voltage and the two given resistors,
you can calculate the currents through these resistors.
You can subtract the calculated currents from the total current.
With this resulting current and the given voltage,
you can calculate the missing resistor value.

Succes,
Bertus

stinky111 likes this.
3. ### dcarson7 New Member

Apr 28, 2011
7
1

stinky111 likes this.
4. ### stinky111 Thread Starter Member

Apr 7, 2011
39
1
Thx for replies..
The circuit is identical to the one you provided,
Just to clarify I will not be building this circuit, it was a question from a past exam that I have been studying & trying to familiar myself with,

dcarson7 likes this.

Apr 5, 2008
15,806
2,389
Hello,

@dcarson7:
The homework help forum is to get help.
Only hints and suggestions to solve the problem are welcome.

@stinky111
Simple parallel circuits

Bertus

Last edited: Apr 30, 2011

Dec 26, 2010
2,147
300
7. ### dcarson7 New Member

Apr 28, 2011
7
1
@bertus - Advice noted. , when I said check RT with R3 value, I was hinting for the OP to make some effort there.
There was nothing asked regarding power but I felt it'd be wise to inform someone new that considerations needed to be made.

@Adjuster - solid point, anything high power I tend to run away from