Parallel and Series Resistor Simplification

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SUMMARY

The discussion focuses on the simplification of a circuit involving parallel and series resistors, ultimately leading to an equivalent resistance of 9 ohms and a specific resistor value 'R' of 15 ohms. The user initially struggled with the simplification process, particularly at a junction with three resistors. Key equations for calculating series and parallel resistances were provided, including Rtotal = R1 + R2 for series and Rtotal = 1/(1/R1 + 1/R2) for parallel configurations. The user successfully resolved the issue by recognizing that a 30-ohm resistor was shorted and could be removed from the circuit.

PREREQUISITES
  • Understanding of series and parallel resistor configurations
  • Familiarity with Ohm's Law and basic circuit analysis
  • Knowledge of resistor equivalent calculations
  • Ability to interpret circuit diagrams
NEXT STEPS
  • Study advanced circuit analysis techniques, including Thevenin and Norton equivalents
  • Learn about Kirchhoff's laws for analyzing complex circuits
  • Explore simulation tools like LTspice for circuit modeling
  • Review practical applications of resistors in electronic circuits
USEFUL FOR

Electrical engineering students, hobbyists working on circuit design, and anyone seeking to improve their understanding of resistor networks and circuit simplification techniques.

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Hi,

I need help simplifying this circuit with parallel and series resistors. I am mainly confused, because there seems to be a point in my simplification where in picture 4 and 5 of my second image where the remaining 3 resistors are connected by 1 node.

I tried to simplify them as resistors in parallel, but I end up with the wrong answer, and this doesn't seem like the correct thing to do.

Homework Statement



The Resistor equivalent of the entire circuit is 9 ohms. And the answer for 'R' is 15 ohms. However I do not know how to obtain this answer.

Homework Equations



Series Resistors = R1 + R2 = Rtotal
Parallel = R2*R1/R1+R2 = Rtotal
= 1/R3 + 1/R2 + 1/R1 = Rtotal

The Attempt at a Solution



Here are the images of my attempted solutions:

image 1 (the problem):
http://img22.imageshack.us/img22/9206/resistor1.jpg

image 2 (my analysis):
http://img22.imageshack.us/img22/4978/resistor2.jpg


Any help would be appreciated.
 
Last edited by a moderator:
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the 30ohm resistor is shorted so just remove it from the network and u'll get the right answer.
 
Yes, thank you.

I actually figured it out before the forum posted my question.
 

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