electromagnetic waves

Discussion in 'General Electronics Chat' started by whale, Dec 21, 2008.

  1. whale

    Thread Starter Active Member

    Dec 21, 2008
    111
    0
    hello.....
    can any one tell me how to make electron to transmit in free space.
    ie,how wireless is made.
    and how it works.
     
  2. theamber

    Active Member

    Jun 13, 2008
    318
    0
    You need to be more specific. You need a volume to explain all that.
     
  3. leftyretro

    Active Member

    Nov 25, 2008
    394
    2
    Wireless is not electrons flowing through free space. Electrons do not travel through free space, rather electromagnetic waves. Radio waves are of the same form as light waves, just at a different frequency.

    See if this reference helps:

    http://en.wikipedia.org/wiki/Electromagnetic_wave_theory

    Lefty
     
  4. whale

    Thread Starter Active Member

    Dec 21, 2008
    111
    0
    thanks for your request senior:)
     
  5. steveb

    Senior Member

    Jul 3, 2008
    2,433
    469
    Isn't electrons traveling through free space the principle of the electron tube? I think you just misspoke here.
     
  6. leftyretro

    Active Member

    Nov 25, 2008
    394
    2
    I said "Wireless is not electrons flowing...."

    I didn't say electrons can't travel in a vacuum. They flow then only because there is a positive charge on the anode to attract them. That is not how radio waves (wireless) propagate through the atmosphere and space. There is no positive charge at receiver's location to attract free electrons, electrons are not involved. Apples and oranges.

    Now if he had asked about lightning then one could talk about electron charge and the resulting ionized current path once a high enough potential is reached.

    I'm certainly not a scientist, nor beyond misspeaking, but I do think I have a handle on the difference between electron current flow and electromagnetic radiation.

    So maybe you misspoke or misunderstood the posters original question?

    Lefty
     
  7. PRS

    Well-Known Member

    Aug 24, 2008
    989
    35
    Lefty is right on the money. Your question confuses two seperate phenomena -- the movement of electrons, as per current through a wire or an electron gun in a Cathode Ray Tube (like your TV picture tube), on the one hand. and Electro-Magnetic Waves on the other. EM waves include visible and invisible light, heat, Xrays, and radio waves -- a big field of study in physics.

    Of the various ways of creating EM waves, we use the fact that current flowing through a wire gives rise to them and they naturally propogate away from their source of origin at the speed of light.

    To make it clear, I hope: The electons in the wire flow through the wire in a circuit, they do not fly away from the wire. But EM waves are emitted from the wire into space.
     
    Last edited: Dec 22, 2008
  8. steveb

    Senior Member

    Jul 3, 2008
    2,433
    469

    I'm sorry, I wasn't clear. I know you have full understanding of all this. I was just pointing out that the phasing of your sentence left some room for someone to misunderstand and think that electrons can't flow in free space. I just wanted to clarify that simple point.

    You actually did say that electrons don't travel in free space, even though you didn't mean it that way. I know you mean in reference to EM radiation, but someone could take that the wrong way, especially the OP.
     
    Last edited: Dec 22, 2008
  9. hobbyist

    Distinguished Member

    Aug 10, 2008
    764
    56
    While on this subject, what medium does electromagnetic radiation travel through, like light waves they say travels as particles, is radio frequency waves particles, they do travel through space, at the speed of light, interesting question...I don't know??
     
  10. Dave

    Retired Moderator

    Nov 17, 2003
    6,960
    145
    In the particle model, light, like RF radiation (waves), can be described as photons which are the elementary particle of EM radiation. The difference is in the energy which in turn is a function of the wave frequency (or wavelength depending on how you describe the wave).

    Dave
     
  11. PRS

    Well-Known Member

    Aug 24, 2008
    989
    35
    Electro-magnetic waves have no mass. Light waves are EM waves and they have no mass. RF EM waves have no mass. Cool, huh? ;)
     
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