Confused about ground

Discussion in 'General Electronics Chat' started by bilnit, Dec 30, 2010.

  1. bilnit

    Thread Starter New Member

    Dec 30, 2010
    1
    0
    After much reading, I'm still confused about this:

    If electricity "wants" to travel from a point of high potential to low potential, and ground is the lowest potential, then how does a circuit continue to work if you put a ground in it?

    To me it seems like electricity would choose to ALWAYS travel toward the ground if given a choice between 1) the ground, and 2) through then load, followed by an opportunity to complete the circuit. Doesn't the first path seem to be the one of least resistance?

    Please help me see the light.
     
  2. edgetrigger

    Member

    Dec 19, 2010
    133
    19
    connection is always like it will flow to ground through the load.
     
  3. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Welcome to the forums.

    The thread you posted in was pretty old - http://forum.allaboutcircuits.com/showthread.php?t=39957&page=2 so it seemed better to move you to your own.

    Current flows between points of differing potential. If we confine ourselves to wires as the conductors, then we have electrons as the charge carriers.

    Electrons carry a negative charge, so current goes from the more negative point to the more positive. Ground in a circuit is a reference point that is used to measure all the other voltages relative to it. Terminology here can be confusing, but a ground in a circuit has no relation to an earth ground, unless an explicit connection is made.

    If a circuit is to function properly, then that path of least resistance to ground must not be allowed to come into existence. You are correct that current will be heaviest where the resistance is less.

    Recall that circuit ground is a reference point, and that circuit voltages may be positive or negative with respect to that ground. Many circuits use bipolar voltage sources.

    But simply having a ground present does not mean a connection from the voltage source directly to it will simply form by itself. A properly designed circuit does not have such connections present. If something happens, it may cause a short circuit where current goes directly to ground and not through the loads, but that is from an accident or component failure.
     
  4. GetDeviceInfo

    Senior Member

    Jun 7, 2009
    1,571
    230
    In normal opertaion, you don't give it a choice. In abnormal opertation, the choice is 1) ground, or 2) providing a hazardous potential.
     
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