determine current needed to drive a speaker

Discussion in 'Homework Help' started by nearownkira, Apr 1, 2008.

  1. nearownkira

    Thread Starter Member

    Feb 19, 2008
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    the speaker I bought said something like 800 ohm 5W, 8 ohm 25W or 8 ohm 25W.is there a formula or something to calculate.
     
  2. mik3

    Senior Member

    Feb 4, 2008
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    do you have the reference number of the speaker?
     
  3. silvrstring

    Active Member

    Mar 27, 2008
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    It sounds like your max current rating would be about 1.76 A if you have a typical 8 ohm speaker. P=(I^2)R. In the same way, P=(V^2)/R. So the voltage would be around 14V. That's what your alternator normally puts out.

    Are you using an amp?
     
  4. nearownkira

    Thread Starter Member

    Feb 19, 2008
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  5. Audioguru

    New Member

    Dec 20, 2007
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    Those are very small 8 ohm speakers. The 50mm one has a max power rating of only 0.25W.
    The max power might be its peak power so then its max RMS power from a sine-wave is only 177mW.

    Then the RMS current at max power is 149mA RMS.
     
  6. nearownkira

    Thread Starter Member

    Feb 19, 2008
    20
    0
    how do you calculate all those number?
     
  7. beenthere

    Retired Moderator

    Apr 20, 2004
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