The Distinction between Series and Parallel.

Discussion in 'General Electronics Chat' started by studiot, Feb 7, 2014.

  1. studiot

    Thread Starter AAC Fanatic!

    Nov 9, 2007
    We have has quite a few threads lately about elementary circuits and the distinction between series and parallel.

    Whilst most connection arrangements can be reduced to either series or parallel, there are some which are neither (or both).

    Consider a single load resistor connected across a source.

    Is it series or parallel?

    Well in a series circuit the same (the same not just numerically equal) current flows in both, and is the total current, whilst in a parallel circuit the total current is divided between the elements in parallel.

    So this arrangement qualifies as a series circuit.

    However for a parallel circuit the same (total) voltage appears across both elements whilst in a series circuit the total votlage appears divided across both elements.
    Last edited: Feb 8, 2014
    THE_RB likes this.
  2. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    Why yes, yes it is.
    GopherT likes this.
  3. GopherT

    AAC Fanatic!

    Nov 23, 2012
    That is like asking whether or not 1 is a prime number. It is a question of semantics, not science.
  4. subtech

    AAC Fanatic!

    Nov 21, 2006

    Series = only 1 path for current to flow.

    Parallel = more than one path for current to flow.
  5. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    I like your analysis.

    I would add that in a "parallel" circuit the current flows through each branch in the SAME direction.

    In series, the schematic may still look "parallel" (like a battery and a resistor) but the current flows in different directions in each branch so it is a series circuit.

    So in use, an LC tank circuit is a series circuit, even though the L and C appear to be in parallel.

    The function is more important than the schematic appearance.
  6. studiot

    Thread Starter AAC Fanatic!

    Nov 9, 2007
    a) Thank you

    b) Are you sure? The circuit mentioned has two nodes, and a single loop which formally is a mesh. If the current is going one way in one part and another way somewhere else where does it reverse?

    Here are some more "parallel" arrangements.

    1) Can you guarantee that the current in R1 is in the smae direction as the current in R2, regardless of other circuit values?

    2) This is often called an anti-parallel arrangement.

    3) How about the oscillatory current in this tank?

    When you delve more deeply the whole subject bears further investigation.
  7. crutschow


    Mar 14, 2008
    I like subtech's definition. Seems to have less ambiguity.
  8. ErnieM

    AAC Fanatic!

    Apr 24, 2011

    Why yes, yes I can.

    I will go even further to specify they have the same sign.
    And a rose by any other name...
    Wow, how about that circuit!

    On a slightly more serious side questions of series or parallel are of little matter when dealing with circuits of any real complexity.