What's the resistance?

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

  1. jut

    Thread Starter Senior Member

    Aug 25, 2007
    224
    2
    What's the resistance across AB?

    [​IMG]
     
  2. recca02

    Senior Member

    Apr 2, 2007
    1,211
    0
    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
    10
    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
    10
    I noticed it too. The way the circuit is designed is misleading.
     
  6. recca02

    Senior Member

    Apr 2, 2007
    1,211
    0
    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;):D. Meaning i perhaps made a similar mistake once:rolleyes:.

    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
    145
    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
    4
    0
    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
    9,411
    896
    What are you talking about?
    The resistors are obviously in parallel.
     
  10. JoeJester

    AAC Fanatic!

    Apr 26, 2005
    3,373
    1,164
    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
    9,411
    896
    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
    3,373
    1,164
    It's been so long since I was a newbie that I suffer from CRS ... Cant Remember S_it.
     
Loading...