How electrically common points have same voltage

Discussion in 'General Electronics Chat' started by ivepoli, Apr 20, 2016.

  1. ivepoli

    Thread Starter New Member

    Apr 19, 2016
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    Hello,
    I read about voltage in capacitor and see that voltage is dependent on distance from the two plates, like gravitational potential energy depends on height.
    But how do electrically common points in circuit have the same voltage? Isn't voltage dependent on location in wire?
     
  2. SLK001

    Well-Known Member

    Nov 29, 2011
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    224
    It is for AC, but not for DC. What are you talking about?
     
  3. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    4,769
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    They don't.. There is no voltage across 2 common points as they are connected
     
  4. SLK001

    Well-Known Member

    Nov 29, 2011
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    It's not the voltage, but the capacitance that is dependent on the distance between the two plates. The voltage doesn't vary.
     
  5. wayneh

    Expert

    Sep 9, 2010
    12,094
    3,033
    Right, if there is a conductive path between two points, meaning they're common, any voltage imbalance causes current to flow and the imbalance quickly disappears. Like water seeking a level, only much much faster.
     
  6. hp1729

    Well-Known Member

    Nov 23, 2015
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    Very low resistance along the wire thus very little difference in voltage. There is a difference but your meter could not measure it.
     
  7. AnalogKid

    Distinguished Member

    Aug 1, 2013
    4,518
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    Yes, but the difference usually is microvolts, too small to measure and way too small to care about.

    Technically, most of the time two points in a circuit are connected there is electron flow (current) from one point to the other. But copper is an excellent conductor, and the resistance in the copper connection is so small relative to the energy being moved that the voltage difference is hard to measure. Microvolt meters and micro-ohmeters are designed specifically for these kinds of measurements.

    ak
     
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