# What's the resistance?

Discussion in 'Homework Help' started by jut, Dec 19, 2007.

1. ### jut Thread Starter Senior Member

Aug 25, 2007
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What's the resistance across AB?

2. ### recca02 Senior Member

Apr 2, 2007
1,211
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12//4= 3
the two resistors are connected in parallel..connected across same 2 points A and B.
think, when can u actually say those are in series?

3. ### cumesoftware Senior Member

Apr 27, 2007
1,330
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Simple. Resistors are in parallel. Resistance is 3Ohm.

4. ### jut Thread Starter Senior Member

Aug 25, 2007
224
2
Yeah yeah, they're in parallel -- I realized that after posting. But a neophyte like myself thought they were in series... I mean, come on, it looks just like a pair of series resistors!

5. ### cumesoftware Senior Member

Apr 27, 2007
1,330
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I noticed it too. The way the circuit is designed is misleading.

6. ### recca02 Senior Member

Apr 2, 2007
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One comes across such situations often in network analysis...and it is really funny since u can assume without regret that one person out there is sure to commit a mistake there and u can look smart explaining it to him. Meaning i perhaps made a similar mistake once.

For the resistors to be in series one must encounter both resistance when traversing the wire from point A to B at once.

7. ### Dave Retired Moderator

Nov 17, 2003
6,960
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Indeed, its quite deceptive. It is often best in circumstances such as these to redraw the circuit in order to confirm that your suspicions are indeed correct. As is the case with learning in electronics we are conditioned to expect circuits to be drawn in a certain way.

Dave

8. ### asimov New Member

Jun 25, 2007
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If it is a text book problem than it is an old trick. Teaches one not to assume anything. The best thing to do is try redrawing the circuit by tracing out the current paths.

9. ### Audioguru New Member

Dec 20, 2007
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The resistors are obviously in parallel.

10. ### JoeJester AAC Fanatic!

Apr 26, 2005
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1,227
Were they obvious the very first time you seen that circuit those years ago?

Recently I spoke with a newbie [not a poster of this forum] who didn't "see" a parallel resistor path. It's not obvious to the newbie. Just as asimov stated
As an experienced person, you should not assume the obvious to you is the obvious to everyone.

11. ### Audioguru New Member

Dec 20, 2007
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I was a noobie such a long time ago that today I can't remember being a noobie.

12. ### JoeJester AAC Fanatic!

Apr 26, 2005
3,402
1,227
It's been so long since I was a newbie that I suffer from CRS ... Cant Remember S_it.