Using a 12 V DC wall wart. Do I need an extra 12 V regulator circuit?

Discussion in 'General Electronics Chat' started by hrstar24, Oct 25, 2011.

  1. hrstar24

    Thread Starter Active Member

    Apr 7, 2009
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    Basically I need to take the wall voltage and provide 3.3 V, 12V, and 30 V DC voltages to power various components in my project. I decided to use a 12 V DC wall wart to convert the wall AC to DC.

    I already got the 3.3 V and 30 V done using a boost converter and a regulator, but now I am stuck on the 12 v.

    I measured the wall wart open circuit, and it is ~12.3 V. I am using the 12 V to provide voltage rails for an op amp, as well as bias a photodiode. My question is do I need to use a circuit to regulate this 12 v from the wall wart, or is a wall wart stable enough? Is there a simple transistor or Zener diode circuit that can be used to provide some power surge protection or something? So far I haven't been able to find any 12 v in 12 v out voltage regulators
     
  2. chrisw1990

    Active Member

    Oct 22, 2011
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    you fancy uploading the schematic so can have a look at the whole thing?
     
  3. hrstar24

    Thread Starter Active Member

    Apr 7, 2009
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  4. chrisw1990

    Active Member

    Oct 22, 2011
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    loook at the comments below the the image. theres one guy who says about using it for a 12V
     
  5. bertus

    Administrator

    Apr 5, 2008
    15,648
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    Hello,

    The mentioned wallwart is regulated.
    From the given link:

    There will be no need for further stabilisation.
    A couple of decoupling capacitors will be needed.
    Decoupling or Bypass Capacitors, Why?

    Bertus
     
  6. chrisw1990

    Active Member

    Oct 22, 2011
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    however, they do link to an unregulated supply tutorial?
     
  7. hrstar24

    Thread Starter Active Member

    Apr 7, 2009
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    Oh wow should have read that lol sorry. So that answers a big part of my question, but I don't have much experience working with diodes in filters... is there an example of a filter circuit that would work that he is talking about?
     
  8. hrstar24

    Thread Starter Active Member

    Apr 7, 2009
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    0
    Maybe just a simple high pass filter would work?
     
  9. bertus

    Administrator

    Apr 5, 2008
    15,648
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    Hello,

    Can you post a schematic of the opamp / photodiode circuit?
    That way we can see where to add extra decoupling if needed, as switching powersupplies can make some noise.

    Bertus
     
  10. iONic

    AAC Fanatic!

    Nov 16, 2007
    1,420
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    It would be nice to know what you plan to operate with the adapter. Will you be using 3.3V, 12V, and 30V all at once?
     
  11. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    I suggest that you don't exceed 500mA with this supply, which is ~80% of its' rating.

    While the SparkFun blurb claims "high quality", the comment entered on October 13 states 3 of 12 they purchased have failed, and the quality of assembly was poor.
     
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