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Understanding of the term 'grounded'

dgupta

May 15, 2014
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May 15, 2014
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Hello all,

I would appreciate any help clearing up some confusions I have with the term 'grounded'. I am aware that when an electron is grounded it loses its charge and reverts to a low energy state. On a battery we have a positive and a negative (GND) terminal.

My confusion is with the concept electrons move from the negative terminal (where there is a surplus) to the positive, doesn't this conflict with the definition of 'grounded' as how can electrons move when they are at a low energy state?

In a battery do electrons flow from the negative terminal where they are supposed to be grounded?

Many thanks,
 

Harald Kapp

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Nov 17, 2011
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Hello dgupta, welcome to the forum.

I am aware that when an electron is grounded it loses its charge
No, an electron always ha a negative charge. It doesn't loose the charge. Elelctrons can move around (the movement of electrons is current) between two different potentials. The diffference in potential is called voltage. Therefore an electron can move from a potential A to potential B if the potential of A is more negative than the potential of B. This is expressed as the voltage between B and A is positive. The electron does not lose charge during this movement, it changes its potential.

The term "grounding" is based on the practice of connecting one pole of a power supply (e.g. mains) to physical ground (earth) see this article. This is usually done for safety purposes and/or to create acommon reference potential ("0V).
From the latter (common reference potential) the term "grounding" has been transferred to mean the reference potential within any circuit, even if there is no connection to physical ground (earth).
If you have a single supply voltage (e.g. battery) it is very common to denote the "-" pole of the battery as ground (short GND). All voltages within the circuit are referred to this potential. This is by convention only. One can also denote the "+" pole as ground, then the other voltages within the circuit are negative with respect to ground.
If you have multiple supplies, you define one potential as ground (0V), typically the "-" pole of the main supply. You may then have voltages positive and negative with respect to this ground. Again, this is only by convention. Any potential can be used as reference.
 
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