Resistor Order

Discussion in 'General Electronics Chat' started by TheRoman, Oct 7, 2010.

  1. TheRoman

    Thread Starter New Member

    Jul 22, 2010
    Hi, i've been struggling to find an answer to this question, its probably a simple one.

    Does it matter what order a resistor and LED ( or any component ) are in. For example:

    Vcc -----resistor------Led------gnd


    Vcc ------led-------resistor------gnd

    Are they the same? If so why?

    Thanks for your time in advance, hope its not a stupid question.
  2. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    In this case, yes they are the same. See:

    Edit: With respect to "any component," then there may be a distinction, depending on the components and how you define functions. If you look at mosfet circuits on this forum, you will see there is a difference between circuits in which the mosfet ("control element" = resistor in your example) feeds the load (led in your example) and those in which the mosfet drains the load. That difference results from the reference potential needed to control the gate of the mosfet.

    Last edited: Oct 7, 2010
  3. bertus


    Apr 5, 2008

    The circuits act the same.
    The resistor is still limiting the current as it is in series with the led.

  4. Wendy


    Mar 24, 2008
  5. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    Electrons are always present from Vcc all the way to ground even when the circuit is off (they don't just start at vcc and then move through the circuit to ground..they are everywhere).. These "electron people" are holding hands and are trying to walk around the circle/circuit. The resistor is the gate keeper (or speed keeper) and tells the electrons how many can pass at a time.. Since these electrons are holding hands they can only move as fast as the one in front or behind them.. So the gatekeeper (resistor) just keeps them moving as fast as he says. So it doesn't matter where the gatekeeper is in the circuit because all the electrons are holding hands and moving at the same pace as the one before or after.
    Once you stop thinking that the power/voltage,etc.. just starts at Vcc and moves from there you will be better off.
  6. TheRoman

    Thread Starter New Member

    Jul 22, 2010
    Thanks everyone for your explainations, links and help. Made it a lot easier to understand.