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How does flow of current result in sound?

  1. Oct 30, 2016 #1
    I understand in a bulb when electrons flow they cause resistance and this heats up the bulb and the gases inside are ionised and they in turn emit light because their atoms become charged. How does flow of electrons cause sound? I know its an advanced explanation but what is the flow actually doing that causes sound?
  2. jcsd
  3. Oct 30, 2016 #2


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    None of that is really right. You seem to be mixing concepts for different kinds of lights (incandescent, fluorescent, etc.).
    You mean how does a loudspeaker work? What reading have you been doing on it so far? I'm sure wikipedia has a good page on how loudspeakers work...
  4. Oct 30, 2016 #3
    In an incandescent (filament) lamp it is the filament vibrating. In a fluorescent lamp it is the ballast vibrating.
  5. Oct 30, 2016 #4


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    say what ??
  6. Oct 30, 2016 #5
    Fair enough. It IS rather unclear.

    (2nd try)
    The electrons don't have a direct effect of creating sound. Any sound generated is due to mechanical vibrations.
    In an incandescent (filament) lamp it is the filament vibrating, usually due to an intermittent connection causing current variations and hence a varying magnetic field around the coiled filament. The changing magnetic field causes the coiled filament to contract and relax. Note that this intermittent contact may be in the filament itself as it is burning out.

    In a fluorescent lamp I have only noticed the ballast vibrating, or the starter switching at startup.
  7. Oct 30, 2016 #6


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    all still very strange :wink: once a filament in a lamp goes open circuit, that's pretty much it for the lamp as far as any operation goes

    lets just wait till the OP returns and
    1) see his response to Berkeman's post #2
    2) find out for sure what sound he is referring to as the OP was extremely unclear as to what was being referred to

  8. Oct 31, 2016 #7


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    Filaments do emit a ringing sound especially when run on a TRIAC or SCR type dimmer. In this case it has nothing to do with an intermittent connection.
  9. Oct 31, 2016 #8
    Yes, I must read and stop making stupid threads.. his post cleared it up..it is mechanical vibrations.
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