# Finding Resistance

1. Mar 28, 2008

### n77ler

[SOLVED] Finding Resistance

1. The problem statement, all variables and given/known data
A number of resistors of values R1 = 3.8 Ω, R2 = 80.0 Ω, and R3 = 20.0 Ω are connected as shown in the figure. What is the resistance between points A and B?

2. Relevant equations

3. The attempt at a solution

Im confused because all I've been calculating is the equivalent resistance, what is the difference between the two?

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2. Mar 28, 2008

### Staff: Mentor

They are just asking for the equivalent resistance of that network, as seen at the entry points A & B. Just use your series & parallel combination rules to reduce the network to a single (equivalent) resistor between A & B, and you will have your answer.

3. Mar 28, 2008

### n77ler

ok thank-you

4. Mar 28, 2008

### Mike Cookson

The Four R1 and R3 are in series thus those five resistors to the right can be combined by adding the value....(4*3.8+20)=35.2Ω
That resistance is in parallel with the R2 thus the combination of the five and this resistor is equal to 1/(1/35.2+1/80) = 24.4Ω (3sf)
Now the total becomes this plus 2*R1

Total = 24.4+3.8*2 = 32.0Ω (3s.f.)

Just incase you were still stuck, that and I like to go back to some easy electronics now and again to remind me that my head hasn't exploded :)

5. Mar 29, 2008

### Snazzy

You shouldn't give out the answers. We're not here to give solutions, but rather how to figure out a problem.

6. Mar 29, 2008

### Mike Cookson

My Apologies, I was only going from what I saw in the rest of the forum.