How many electrons are in 1mA ?

Discussion in 'General Electronics Chat' started by RRITESH KAKKAR, Jan 16, 2016.

  1. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
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    Hello,
    How to find electrons flowing in few mA current?
    example: 1mA how much electron are there?

    charge on electron is = 1.6 x 10^-19C
    Q=N*e
    N=q/e
    N=1/1.6x10^-19
    n=0.625x10^19
     
  2. DickCappels

    Moderator

    Aug 21, 2008
    2,658
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    Can you take a try at this first? I think your question is best worded as "How many electrons per second does 1 milliamp represent."
     
  3. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
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    1ma = 0.001A
     
  4. ISB123

    Well-Known Member

    May 21, 2014
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    If there is 6.25 10^18 electrons at 1A/s how much there would be at 1mA/s?
     
  5. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    I think ISB123 means 1 Amp.sec and 1mA.sec.
     
  6. Roderick Young

    Member

    Feb 22, 2015
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    168
    One Ampere means that on average, one Coulomb of electrons are passing a given point per second, going in the same direction. If the same electron loops around and passes that point again, it counts as another one.

    One milliamp is 10^-3 amp, which means that 10^-3 Coulombs are passing that point.

    A Coulomb is a large number, about 6.24 x 10^18.

    So one milli-Amp means 6.24 x 10^15 electrons per second passing through a given point.
     
    JohnInTX likes this.
  7. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
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    Then what is Voltage ?
    10V 20V are they presure or moving speed of electrons?
     
  8. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
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  9. Roderick Young

    Member

    Feb 22, 2015
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    Voltage can be thought of as pressure. Current can be thought of as volume of flow. The actual speed of individual electrons is not something that usually matters in electronics, although it might in physics. Although an electric field propagates at basically light speed, electrons have a surprisingly low average velocity in the wires in our electronics, I've heard.

    If this is homework or for a test, be very careful about units. Current has the units of charge / time, in the above case, electrons per second. In a casual conversation, an engineer might know what you mean, but it is technically incorrect, and would likely be marked wrong on a test.
     
  10. crutschow

    Expert

    Mar 14, 2008
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    Yes, the slow movement of electrons in a wire at typical current levels is because there are many more free electrons in a volume of the wire conductor (assuming 1 per atom) than there are in a coulomb of charge moving through that conductor.
     
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