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What does it mean to be ''in series'' or ''in parallel''

  1. Mar 10, 2014 #1

    Maylis

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    Hello,

    I've had a qualm over the definition of ''in series'' or ''in parallel''. I want to know, when two components are in series, does that mean that they share the same current, or does it mean that the components only share one node on one side of the component with each other.

    Similarly, does being ''in parallel'' mean that the components have the same voltage, or does it mean that they are sharing at least 2 nodes with each other. Meaning, the components are connected to the same nodes on each side of the component.

    I think if the definition regarding the node sharing is incorrect or not general, then I will continue to have problems identifying circuits in parallel or series, especially when given odd arrangements (which is of undoubtedly what will be on the exams for my circuit analysis class) because it is less clear to know if two components share a voltage or not.
     
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  3. Mar 10, 2014 #2

    SteamKing

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  4. Mar 10, 2014 #3

    Maylis

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    Okay, that article says about the current being the same in series and the voltage being the same in parallel. Great. That doesn't do me so much good because on a circuit it isn't always obvious if the voltage is the same. I want to know if my node definition holds. Yes, I know I want to force my own definition because it makes problems easier to solve for me.
     
  5. Mar 10, 2014 #4

    PhysicoRaj

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    The words are self explanatory: Series refers to an end to end connection. Parallel means connected between the same points.
     
  6. Mar 10, 2014 #5

    phinds

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    I'd say that's a very bad way to describe series, since you're definition would allow the middle node to go elsewhere and then it would NOT be series.

    Maylis, the definitions are

    Series --- the two elements have a node in common that does not go anywhere else, so the same current flows through both.

    Parallel --- the nodes have BOTH nodes in common so the voltage is the same across them.
     
  7. Mar 10, 2014 #6

    PhysicoRaj

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    I meant to say 'end to end one after the other'. The inclusion of 'not going anywhere' does it. Thanks for correcting me.
     
  8. Mar 10, 2014 #7

    Maylis

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    Okay awesome, that was what I was leaning towards. However, I want to clear this up. Can the components have two nodes in common, but one node has a wire branching off somewhere else, yet the two components are still in parallel.
     
  9. Mar 10, 2014 #8

    phinds

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    Yes, you wouldn't have much of a circuit otherwise :smile:

    In a parallel construct it is irrelevant what the nodes do outside of the construct. In a series construct, you can't have the center note going off somewhere else because that would change the current, probably making the current different in the two elements which violates the meaning of "series".
     
  10. Mar 10, 2014 #9
    Series connection: two devices are in series if they connect to each other at one node AND NOTHING ELSE CONNECTS THERE.

    Parallel connection: two devices are in parallel if they connect to each other at TWO nodes.
     
  11. Mar 10, 2014 #10

    phinds

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    How is that different than what I said in post #5?
     
  12. Mar 10, 2014 #11
    Not different, just clearer (I hope)
     
  13. Mar 10, 2014 #12

    Dale

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    Note that series and parallel are not essential concepts. They are useful for simplification and understanding, and you have to learn them to pass your tests. But you can solve any circuit without ever identifying any series or parallel elements, and some configurations (e.g. Wheatstone bridge) cannot be described as either series or parallel.

    So don't stress out too much about it.
     
  14. Mar 10, 2014 #13

    phinds

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    Good points
     
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