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Homework Help: Is my Power Supply Circuit correct in the recreated version?

  1. Oct 5, 2016 #1
    1. The problem statement, all variables and given/known data
    So the circuit drawing is in this link http://i.imgur.com/jVYm5La.jpg . Basically, we have to create a power supply circuit and using Livewire and PCB wizard program in conjunction, I created this circuit

    2. Relevant equations

    3. The attempt at a solution


    I can't seem to know exactly if this is correct or wrong when I recreate this using the program. I tried using the Play function in Livewire and the green current seems to have no Voltage. I'm also wondering if I misplaced some polarity of the Voltage regulators there.

    Sorry, I'm a bit new to using these programs
    Last edited by a moderator: Oct 5, 2016
  2. jcsd
  3. Oct 5, 2016 #2


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    Homework Helper
    Gold Member

    A couple of observations: Your pots are not correctly connected. F1 is not serving any purpose.
  4. Oct 5, 2016 #3


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    Staff: Mentor

    Looks like the fuse is in the wrong place.

    I think you will need a pair of bridge rectifiers—one for each side of the power supply.

    Are you going to use a transformer between the 220V and your rectifier?
  5. Oct 5, 2016 #4

    I completely forgot though, the transformer is a step-down one so the input would only be 25V

    Edit: How about the Voltage regulators? Is there something wrong with it?
    Last edited: Oct 5, 2016
  6. Oct 5, 2016 #5


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    Staff: Mentor

    By this I mean one bridge rectifier for the positive regulator, and a second bridge rectifier for the negative regulator.

    I think you should search on google for a few schematics of a dual regulated power supply, and model your circuit on those.
  7. Oct 5, 2016 #6


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    Science Advisor

    The output terminals (both of them) are connected to the wrong spot.

    I second the suggestion by @NascentOxygen about a Google search for schematics.

    Although your basic circuit architecture can work in some conditions, please consider using a transformer with a Center Tapped secondary or two individual secondaries.
    Last edited: Oct 5, 2016
  8. Oct 11, 2016 #7

    rude man

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    Homework Helper
    Gold Member

    Yes, very. You're mixing up the output vs. ref pins and then the circuit needs to be still further reconfigured (basically R1 ⇔ R2 and R3 ⇔R4 value-wise). Look more carefully at how the lm317 is supposed to be hooked up. Same with the lm337. As in here http://www.ti.com/lit/ds/symlink/lm317.pdf
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