clean 12vdc car power

Discussion in 'The Projects Forum' started by StealthRT, Jun 24, 2013.

  1. StealthRT

    Thread Starter Active Member

    Mar 20, 2009
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    I am looking to get a constant, clean 12v from my cars 12v line. I am wondering if all I am in need of to pull this off would be a simple 12v fixed regulator?

    The 12v would be hooked up to a pico motherboard (19v max input), 7" lcd monitor and an arduino.

    I did find this schematic here:
    [​IMG]

    So would a simple regulator be good or not? Will it need a heat sink?
     
  2. wayneh

    Expert

    Sep 9, 2010
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    Yes! The system voltage could be as high as 15V or so. Dropping 3V at 5A will generate 15W of heat to be dissipated. Kind of a lot. Of course if your load is much less than 5A, the power as heat will be less.

    I'll leave it to others to comment on your zener regulator strategy. Looks good to me, but that doesn't mean much.

    You'll never get 5A through that 2N3005 with only a 1kΩ base resistor.

    Now that I think about it, I'm not sure how well that arrangement can hold the base voltage steady if the load varies.
     
    Last edited: Jun 24, 2013
  3. MrChips

    Moderator

    Oct 2, 2009
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    Last edited: Jun 24, 2013
  4. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    Wondering why you need a clean 12V when the pico is rated to 19V..
     
  5. SgtWookie

    Expert

    Jul 17, 2007
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    Automotive environments are brutal; you may see drops below 10v when cranking and spikes exceeding 60v during load dumps. A simple linear regulator will waste some power, and won't be of any help during low voltage drops; you would need a switching regulator to handle that.

    I'm on my cell, so don't have a circuit for you offhand.
     
  6. StealthRT

    Thread Starter Active Member

    Mar 20, 2009
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    SgtWookie! Good to see you around again! :)

    The NUC is rated from 12v-19v. Not sure of the wattage but the old ones are rated at 65w and i have no idea how many amps. The LCD and arduino... well i really have no idea right now. Maybe 0.50amps for the LCD and less for that on the Ardunio.

    Someone on another forum suggested this:
    [​IMG]

    Let me know when you are able to get a schematic, SgtWookie!

    And thats for the feedback, MrChips & wayneh.
     
  7. StealthRT

    Thread Starter Active Member

    Mar 20, 2009
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    Do you have a schematic yet, sgtWookie?

    Thanks!
     
  8. SgtWookie

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  9. wayneh

    Expert

    Sep 9, 2010
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    You'd still need to protect it from a 60V spike, right?
     
  10. Shagas

    Active Member

    May 13, 2013
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    Is it possible to get a 20-30volt Varistor to protect against those high spikes?
     
  11. SgtWookie

    Expert

    Jul 17, 2007
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    Shagas likes this.
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