substituting wall wort for 2 batteries

Discussion in 'General Electronics Chat' started by lokeycmos, Mar 7, 2011.

  1. lokeycmos

    Thread Starter Active Member

    Apr 3, 2009
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    so im building an audio project that runs off of 2 9 volt batteries. i would like to substitute a wall wort. the problem is that the schematic has the two batteries in series with a ground inbetween. i attached a schematic. is this possible with a wall wort, weather it is 9v or 18volt? cause i have both. if this is not possible, could you please explain how this can be done as simple as possible with the least amount or parts?
     
  2. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    You can make a pseudo ground using another op amp.

    Creating a Virtual Power Supply Ground

    Since this is a low power circuit Figure 5 will probably work (add a capacitor to the voltage divider, as well to the total power supply).
     
  3. lokeycmos

    Thread Starter Active Member

    Apr 3, 2009
    432
    7
    thanks for the input. it gave me ideas. i ended up using this voltage divider. i was able the solder it together inside the walwart and add an extra wire.
     
  4. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    [​IMG]

    Those resistors are bit high, since you are using a 50KΩ pot connected to ground. Think about dropping them about 1/10 the value, or using the 3rd op amp I suggested.

    On the other hand, if it works, never mind.
     
  5. lokeycmos

    Thread Starter Active Member

    Apr 3, 2009
    432
    7
    it works. Thank you!
     
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