What is an electrical current ?

Discussion in 'Physics' started by eis3nheim, Nov 20, 2014.

  1. eis3nheim

    Thread Starter New Member

    Nov 20, 2014
    I know that an electrical current is the flow of electrons but how does the flow of electrons could generate electricity ? And does the charge of electrons is consumed during the flow ?
  2. crutschow


    Mar 14, 2008
    From Wikipedia:
    Electricity is the set of physical phenomena associated with the presence and flow of electric charge. Electricity gives a wide variety of well-known effects, such as lightning, static electricity, electromagnetic induction and electrical current.

    Thus an electric current is one aspect of electricity.

    Electrons are not consumed by their flow. They just slowly move through the conductor. They are actually a basic subatomic particle which are impossible to alter (charge or otherwise), at least by any normal conditions on earth.
    MrAl likes this.
  3. studiot

    AAC Fanatic!

    Nov 9, 2007
    It depends what you mean by consumed.
    Charge can participate in several different processes and obeys the law of conservation of charge which says

    In any process there is the same net (total) charge at the end of the process as there was at the beginning.

    Electrical current is a process, so obeys this law.

    I'm not sure what you are asking by the first part of your question, can you expand on it?
    Last edited: Nov 20, 2014
  4. sirch2

    Well-Known Member

    Jan 21, 2013
    "how does the flow of electrons generate electricity?"

    The flow of electrons IS what is conventionally regarded as electricity. Electrons convey the electro-magntic force, so for example I can drive a generator that moves electrons and then those electrons can drive a motor, the thing that provides the "power" is the electro-magnetic force. The usual analogy is of having water flowing through a pipe, I could pump water into the pipe and then use the force conveyed by the water to turn a turbine.
  5. MikeML

    AAC Fanatic!

    Oct 2, 2009
    Not exclusively a flow of electrons. A better statement is that an electrical current is a movement of charged particles. Recognize that there are other things beside electrons that can carry electrical charges and move about...
  6. amilton542

    Active Member

    Nov 13, 2010
    One thing I find confusing is that the flow of charge is not a one way street. It's bi-directional. You could be feeding a load but you could also find that you have harmonic noise contaminating the system that you're feeding. I picture it as a two way street. Something's flowing one way, something "else" is also flowing in the other way.
  7. bertus


    Apr 5, 2008
  8. JDT

    Well-Known Member

    Feb 12, 2009
    Information, or energy can flow the other way. Or both ways simultaneously.

    A practical example:
    Imagine a water pipe. Water is flowing away from you down the pipe. You have sensors that measure flow and pressure. At the far end there is a valve. Someone partially closes the valve. Even though the water never stops flowing, you can tell that something has changed at the far end.

    So the direction of travel of the "stuff" does not effect the direction of travel of information. Any help?
    studiot likes this.
  9. BR-549

    Well-Known Member

    Sep 22, 2013
    Post #8.
    Energy always flows one way.
    1. because energy needs time to move.
    2. and it takes time for inertia reaction.
    3. all energy is orthogonal. It takes time to switch dimensions.
    4. all information is orthogonal.

    You can tell there has been a change from the top of the water pipe.......but it takes time.
    It takes the time for inertia to react and it takes time for the transmission distance.

    For the speeds we use now.......Full duplex is only apparent.
  10. Wendy


    Mar 24, 2008
    To answer more directly electricity is the movement of charge carriers, what they are isn't that important. For us, with out physics and knowledge, it is mostly electrons, but it can be ions (atoms) or some other atomic particle (like positrons). What causes the movement is the Electric force, which can be created by static, movement of a conductor through a magnetic field, or any number of other ways. We almost always convert one form of energy into another, movement into electricity (or EMF potential) or chemically in the case of a battery.

    It is the shear number of ways we can accomplish the same things that make the subject confusing.
  11. studiot

    AAC Fanatic!

    Nov 9, 2007
    Was that pun intended, Bill, or do you sometimes conduct your chemistry outside the case?

  12. Wendy


    Mar 24, 2008
    Not any more. Though I have thought of repeating some juvenile experiments with lemon juice, coins, and 3D printed cells.