Equivalent Resistance of a Ciruit

AI Thread Summary
The discussion focuses on calculating the equivalent resistance of a circuit with specific resistor values. Participants suggest methods for combining resistors in series and parallel, with some initial confusion about the arrangement. The correct approach involves combining R3 and R4 in series, then placing R5 in parallel with that combination, followed by adding R2 in series. Additionally, R6 and R7 should be combined in series and then placed in parallel with R1. Ultimately, the final equivalent resistance can be calculated using the parallel resistor formula for the resulting combinations.
Kajayacht
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1. Find the equivalent resistance of the circuit as shown in the diagram below; where R1 = 1 Ω, R2 = 2 Ω, R3 = 2 Ω, R4 = 4 Ω, R5 = 1 Ω, R6 = 1 Ω, and R7 = 2 Ω.
[URL]http://img21.imageshack.us/i/prob06v2.gif/[/URL]

http://img21.imageshack.us/i/prob06v2.gif/

Homework Equations



R(parallel) 1/R(total) = 1/R1 + 1/R2
R(series) R(total) = R1 + R2

The Attempt at a Solution



I know I can do this one, its easy. But the arrangement of the resistors is throwing me off

I think I can take R3 and R4 in series, then take R5 in parallel with R3,4, take that in series with R2.

Then R7 and R6 are in series, and R7,6 is in parallel with R1. R1,7,6 in series with R2,5,3,4

Is this right?
 
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not 100% on this but here's my help. id do r3,4 in a series, then Rt of that with r5 in a parallel. then the rt3,4,5 with R2 in a series. r7 and r6 are a series so just add those. then i believe you can just do the 3 final resistances all in one parallel circuit.
 
Kajayacht said:
I know I can do this one, its easy. But the arrangement of the resistors is throwing me off

I think I can take R3 and R4 in series, then take R5 in parallel with R3,4, take that in series with R2.

Then R7 and R6 are in series, and R7,6 is in parallel with R1.

This is correct.

Kajayacht said:
R1,7,6 in series with R2,5,3,4

Is this right?

This is not correct.
 
After you have added together R7 and R6, you should have 3 resistors in parallel:
1. R1
2. R6 + R7
3. The resistor you got from merging R2, R3, R4 and R5

Use the parallel resistor formula on all three to get R Total

Kajayacht said:
...the arrangement of the resistors is throwing me off

When I used to have this problem, I found that redrawing the circuit makes it easier to see which resistors are in parallel :)
 
is what i wrote correct?
 
Thanks guys, I got it now. R1,7,6 should be in parallel with R2,5,3,4 not series.
 
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