a query regarding ground

Discussion in 'Homework Help' started by jeyshree07, Jan 9, 2011.

  1. jeyshree07

    Thread Starter New Member

    Jan 5, 2011
    2
    0
    hello,
    when i was surfing through the net i found that ground has zero potential.that is potential difference between any two points in ground is zero.why is it so?
    what is the relation ship between that and grounding electronic devices to ground?
    thanks in advance.
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Let's start with the concept of ground, as opposed to an actual connection to earth. Ground in a circuit is, by definition, a point of zero potential. The other voltages in the circuit are referenced to ground, and take their magnitudes and polarities with respect to ground.

    Consider ground as a wire, or trace on a PCB. any two points should have identical potential.

    Unless there is an explicit connection between the two, there is no relationship between earth ground and some circuit ground. One voltage that is not related to another is said to float.
     
  3. raybo

    Member

    Oct 18, 2008
    22
    0
    You reading posting from someone that does not know. A GROUND CAN NEVER BE ZERO volts not unless it is not carrying any current and the measuring is done at the very same point. Ground is a reference point to any circuit it can be positive or negative the word GROUND is to imply a virtual same potential VIRTUAL is not zero.
     
  4. retched

    AAC Fanatic!

    Dec 5, 2009
    5,201
    312
    What? Ground is at zero volts ALWAYS, when referenced to ground. ;)

    Potential difference is what creates movement of current.

    If you had a 9v battery, and the "ground" was at 6v for some crazy reason, you would only have 3v flowing through the circuit.

    That 9v, is ONLY 9v when measured from a 0v point.

    If GND was -9v and you had a 9v source, you would THEN have 18v running through the circuit.
     
  5. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    To raybo:

    I have no idea where your ideas about ground came from, but they are not correct. Your statement
    is just incoherent enough that it is impossible to make sense of it.

    Where did your understanding of "ground" come from?
     
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