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Quick blow fuses ?

Discussion in 'Electronic Basics' started by little billy, Aug 3, 2004.

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  1. little billy

    little billy Guest

    Hello all,

    A question about fuses:

    If a Quick Blow (glass type, 20mm) fuse is rated 250V 1A
    can I use it to protect a 9v ni-mh battery as well, or
    will it only blow if the voltage is 250 ?
  2. The fuse blows at the same current regardless of the voltage but the
    enclosure is designed to provide containment of the arc at 250v.
    So the answer is yes :)
  3. Don Bruder

    Don Bruder Guest

    It doesn't care about the voltage. It'll blow if something manages to
    draw more than an amp (or close to it - fuses are pretty accurate, but I
    doubt that one has ever been made that's *EXACT*) through it at anywhere
    from a voltge that's barely measurable, on up through 250 volts (And
    beyond, but read on) The 250 rating is all about "When this puppy blows,
    there's gonna be an arc that we don't want hitting anything else - This
    fuse is designed to soak up, contain, or otherwise safely handle the arc
    that a 250 volt source would produce." Which means that for a 9 volt
    application, the "anti-arc" capability is overkill. It won't do any
    harm, but it's "wasted effort", in a manner of speaking. Particularly if
    you can get a 1 amp, closer-to-9-volts fuse for lower cost. (Not that
    the cost of the fuse means much in a one-off situation like yours, but
    even a penny difference in the cost of a part can make a significant
    difference when talking about a production run of
    who-knows-how-many-million units)
  4. Rich Grise

    Rich Grise Guest


    (he said "only ... 250")

  5. little billy

    little billy Guest

    Thanks for both replies
  6. Hmm, still havent found something to do Rich ?? :)
  7. Tom Biasi

    Tom Biasi Guest

    You already got your answers but I would like to add:
    The fuse that you describe is probably expecting AC. You would be better off
    with an automotive fuse, they are usually rated 32VDC.
    There is a slight difference in performance, probably not of any concern to
    you now but I mention it just for you education since your previous posts
    indicate to me that you want to learn.
    Best Regards,
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