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Voltages from the PSU

Discussion in 'Hardware' started by reksuk, Jan 4, 2008.

  1. reksuk

    reksuk New Member

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    Hiya peeps

    I have a question for you, I am currently in the process of completing my A+ and have been asked a question regarding the voltages from a PSU - now I know that most of this is not in the final exam, but as an inquisitive person its bugging now :blink, so please help me.

    The Question is:

    Can you match each component with the voltage from the PSU that each one uses?

    A. -5V
    B. +3.3V
    C. 0V
    D. +12V
    E. +5V
    F. -12V


    Motherboard
    Disk Drives
    Serial Port Circuits
    ISA Bus Cards
    Most Newer CPU's
    Ground


    Thanks
     
    Certifications: HND Electrical & Electronic Engineering
    WIP: A+ Certification
  2. hbroomhall

    hbroomhall Petabyte Poster Gold Member

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    My selection would be as follows:
    -5V ISA Bus Cards
    +3.3V 'Most newer CPUs'
    0V Ground
    +12V Disk Drives
    +5V Motherboard
    -12V Serial Port

    There are a number of problems here, not least the one of 'how old are we talking about here?'!

    AFAIK the -5V rail is now optional - almost nothing uses it any longer. Serial ports used both +12 and -12 (see the RS232 spec for why) but serial ports are slowly disappearing, and the -12V can easily be derived with another chip.
    The 'most newer CPUs' is a bit of a giveaway as to how old the question is. CPUs have reduced from 3.3 some time ago, and 5V CPUs are now *very* old. :biggrin

    Edit: There is the further problem in that the main voltages are used all over the place - not just on the parts mentioned!

    Harry.
     
    Certifications: ECDL A+ Network+ i-Net+
    WIP: Server+
  3. reksuk

    reksuk New Member

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    Thanks for the reply - it makes a little bit more sense now.

    Like you said all the voltages are used all over the place. I have a feeling this question was designed for general purposes only (very basic guidelines) :rolleyes:

    Like I said thanks for getting back to me - much appreciated:D
     
    Certifications: HND Electrical & Electronic Engineering
    WIP: A+ Certification

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