Confused over this Series-Parallel Circuit

thakid87

Joined May 23, 2009
121
Hello all.

Attached is a copy of a circuit that I am having an issue with.

According to my textbook, total resistance is 852 ohms, but I am getting a calculation of 574 ohms.

Can anybody show me where I am going wrong?

t_n_k

Joined Mar 6, 2009
5,448
I also get Rtot=573.76Ω, which is close enough to your answer. Did you transcribe the circuit exactly as shown? If so the book is wrong.

JoeJester

Joined Apr 26, 2005
4,074
When redrawn, the circuit looks like the attachment and is closer to the textbook answer.

t_n_k

Joined Mar 6, 2009
5,448
When redrawn, the circuit looks like the attachment and is closer to the textbook answer.
Huh? That's not the OP's question.

Thav

Joined Oct 13, 2009
82
It is, but the reference designators come are a little close to the values so it's hard to read.

I get 851.7 by doing the two parallel combinations on the right hand side, combining those in series, then doing the parallel combination of the left and right hand side.

yasir_66

Joined Jun 25, 2009
71
your book answer is correct i also verified as i get Rt=851.8 ohms.
Resolve your circuit may be you making mistake in observing diagram.
Note that R2 & R5 is in parallel & R3 & R4 also in parallel.
Then add R25 & R34 as this is in series & finally it is again paralleled with R1
your final calculation should be in using parallel formula for R1 & R2345.

hobbyist

Joined Aug 10, 2008
887
doesn't the R1, get shorted by the volt. source being shorted?

What terminals, are the resistances being measured from? (left side or right side of circuit)
I'm assuming right side.

Last edited:

t_n_k

Joined Mar 6, 2009
5,448
your book answer is correct i also verified as i get Rt=851.8 ohms.
Resolve your circuit may be you making mistake in observing diagram.
Note that R2 & R5 is in parallel & R3 & R4 also in parallel.
Then add R25 & R34 as this is in series & finally it is again paralleled with R1
your final calculation should be in using parallel formula for R1 & R2345.
Agreed - my error as well. Sorry for the distraction.

Thav

Joined Oct 13, 2009
82
doesn't the R1, get shorted by the volt. source being shorted?

What terminals, are the resistances being measured from? (left side or right side of circuit)
I'm assuming right side.
I assumed we were talking about the equivalent resistance seen as a load to V1.

JoeJester

Joined Apr 26, 2005
4,074
I assumed it was the total resistance (load) across V1.

I started at the negative terminal and imagined how the current flowed to the positive terminal of the voltage source.

JoeJester

Joined Apr 26, 2005
4,074
doesn't the R1, get shorted by the volt. source being shorted?

What terminals, are the resistances being measured from? (left side or right side of circuit)
I'm assuming right side.
There was no indication by the OP this was a thevenin problem. If there were, the output nodes would have been identified.

hobbyist

Joined Aug 10, 2008
887 