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12v dc power distribution circuit

Discussion in 'Electronic Basics' started by John Popelish, Apr 11, 2007.

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  1. Might be easy, might not.

    How much current do each of the 3 volt loads need?
    Do any signals communicate between these 4 circuits?
    This is a way of asking if these circuits need to be
    isolated from each other or may share a common negative or
    positive supply rail.
     
  2. asmo

    asmo Guest

    Hi I'm building a circuit bent instrument with several circuits in it.
    I want to run them all off one power supply rather than several
    different battery packs, I want to run 4 3v dc circuits from a 12v dc
    power supply, can anyone point me to a schematic?

    Cheers
    Ed
     
  3. ehsjr

    ehsjr Guest

    -----
    +12 ---+---Vin|LM317|Vout---+---+---> +3
    | ----- | |
    | Adj [R1] |
    | | | |+
    [C1] +----------+ [C2]
    | | |
    | [R2] |
    | | |
    Gnd ---+---------+--------------+

    C1 = .1uF
    C2 = 10 uF
    R1 = 240
    R2 = 336

    Above is a simple voltage regulator circuit based on
    the LM317 chip that will provide 3 volts output.
    Your answers to John's questions will determine whether
    you can use it in your project.

    Ed
     
  4. asmo

    asmo Guest

    I'm not sure about the current, it consists of the circuits from 2
    vtech tiny touch phones,early learning toys, which run on 2 AA
    batterys each.
    The 16 pins from each IC are routed to a patch bay so, yes there is
    some cross wireing, the other 2 circuits are simple 555 astable
    circuits which act as LFO's which can be patched into various points.
    Ed
     
  5. The simplest way to get several different 3 volt supplies
    from a 12 volt main supply is probably to use linear
    regulators, like LM317T, programmed with a pair of resistors
    to produce a 3 volt output. If the 3 volt loads draw more
    than about 50 mA, you will need heat sinks on the regulators
    to keep them from overheating.

    See:
    http://cache.national.com/ds/LM/LM117.pdf

    This arrangement would require that the negative side of the
    12 volt main supply were common to all loads.
     
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