(adsbygoogle = window.adsbygoogle || []).push({}); Equivalent Resistance question HELP!!!

1. The problem statement, all variables and given/known data

The following diagram shows part of an electrical circuit. Find the equivalent resistance between points A and B of the resistor network.

Here is the circuit in question : http://img182.imageshack.us/img182/8742/physicsyf0.th.png [Broken]

2. Relevant equations

R_s = R_1 + R_2 + R_n

R_p = (1/R_1 + 1/R_2 + 1/R_n)^-1

3. The attempt at a solution

I figured out the equations listed above...we have not discussed this in lecture yet (and the hw is due tomorrow before our recitation so I cant get help) so I tried the best I could by reading the text. Here's what I think...

The 28 ohm, 5 ohm, and 23 ohm resistors are in a series so they can be replaced by a 56 ohm resistor. The same can be said about the 38, 8, and 7 ohm resistors being replaced with a 73 ohm resistor. Now, the 9 ohm, the 73 ohm, and 56 ohm resistors are parallel so using the R_p equation:

R_p = (1/9 + 1/73 + 1/56)^-1 = 7.00 ohms

The correct answer is 8 ohms...what am I doing wrong? Do I not understand the concept of series and parallel circuits correctly? Thanks in advance to anyone who helps.

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Equivalent Resistance question HELP

**Physics Forums | Science Articles, Homework Help, Discussion**