# Equivalent resistance of simple circuit

• nil1996
In summary, the conversation discusses finding the equivalent resistance of a circuit and various methods for simplifying the circuit, including using the symmetry of the circuit and the Y-Delta transforms. The conversation concludes with the suggestion to use the transforms to reduce the network to a single resistance.

## Homework Statement

Find the equivalent resistance of the following circuit.
http://img706.imageshack.us/img706/9644/zkz7.png [Broken]

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## The Attempt at a Solution

I am not able to find out which are resistors are in series and are in parallel.Is there any special method to solve these problems?

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Think about drawing this in a different way so you can see the parallel and series resistors more clearly

Use the symmetry of the circuit. There is a plane about which the circuit is symmetrical. By symmetry all the points in this plane are equipotential. Armed with this information you can simplify this circuit by removing a resistor as no current flows through it.

consciousness said:
Use the symmetry of the circuit. There is a plane about which the circuit is symmetrical. By symmetry all the points in this plane are equipotential. Armed with this information you can simplify this circuit by removing a resistor as no current flows through it.

thanks a lot!:thumbs:
i solved the problem

This network is an example of non-parallel/non-serial. The direct method is to use the Y-Delta transforms: http://en.wikipedia.org/wiki/Y-Δ_transform

Then you can slowly reduce the network to a single resistance. The symmetry argument is very clever ... but the transforms work even when you are not feeling clever!