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    What polarity does USB provide a device?

    Discussion in 'Hardware Components and Aftermarket Upgrades' started by Dead1nside, Sep 10, 2008.

  1. Dead1nside

    Dead1nside Notebook Geek

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    I've just bought an aftermarket 5v DC power supply in order to power my external hard drive which is usually powered from a USB port. I was wandering if anyone could tell me what polarity does the USB port provide, central-positive?

    Thanks for your time.
     
    Dead1nside, Sep 10, 2008
    #1
  2. miro_gt

    miro_gt Notebook Deity

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    not that I have measured it, but in general the ouside shell is the ground. This provides screening for the internal lines from the outside disturbances
     
    miro_gt, Sep 10, 2008
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  3. Zenica

    Zenica InterArmaEnimSilentLeges

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    The two outside leads are power and common.
    The inside leads are the signal leads.

    Use a DVOM for polarity.
     
    Zenica, Sep 10, 2008
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