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Amp question

  1. Apr 10, 2004 #1
    How long will a device drawing 8 mA last on a 12 v bat that has a 25mAh?


    25/8 = 3.125 hours?
     
  2. jcsd
  3. Apr 10, 2004 #2

    chroot

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    You got it.

    - Warren
     
  4. Apr 10, 2004 #3
    is there a bat as small as a watch bat that can produce that much mAh at 12v?
     
  5. Apr 10, 2004 #4

    chroot

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    Not that I know of.

    - Warren
     
  6. Apr 10, 2004 #5
    what is ur mAH for watch bat?
     
  7. Apr 10, 2004 #6

    chroot

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    Hell if I know, but I've never seen a 12V watch battery. Most battery chemistries in use today are 1.5 volts or so -- they'd have to pack 8 cells into that watch battery package to get 12V, and I don't think it's been done.

    - Warren
     
  8. Apr 10, 2004 #7
  9. Apr 10, 2004 #8
    Electrical current and pressure

    Voltage is electrical pressure, and it is analogous to water pressure. We don't need to know what the voltage is to answer this; we just need to know that it is considered consistent throughout the problem. The question should be stated as:How long will a device drawing 8 mA at a particular given voltage last on a battery that has a capacity of 25mAh at the same given voltage?.



    Yes, if the question is stated as I corrected above.
     
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