Converting Positive Voltage to negative Voltage

Discussion in 'The Projects Forum' started by Siyom, Aug 9, 2012.

  1. Siyom

    Thread Starter Member

    Aug 9, 2012
    33
    0
    Can anyone suggest a way i can convert voltage from a 9 volt battery into -9 volts,I dont want to switch polarities I just need a fixed circuit i can use.
     
  2. BSomer

    Member

    Dec 28, 2011
    433
    106
    reverse the battery leads...
     
  3. t06afre

    AAC Fanatic!

    May 11, 2009
    5,939
    1,222
    How about using two 9 volts batteries? If you for some reason only need -9 volt remove one of the batteries
    [​IMG]
     
  4. Siyom

    Thread Starter Member

    Aug 9, 2012
    33
    0
    I'm not allowed to reserve battery polarities,this circuit will work alongside microcontrollers and OP-AMPs
     
  5. n1ist

    Active Member

    Mar 8, 2009
    171
    16
    If you only need a small amount of negative rail, you can use a capacitive charge pump circuit like the 7660 or even make one with a spare timer output on your micro driving a capacitively isolated doubler. If you have a MAX232 serial port level shifter on board, you may be able to steal a bit of V- from it.

    /mike
     
  6. debjit625

    Well-Known Member

    Apr 17, 2010
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    186
  7. bountyhunter

    Well-Known Member

    Sep 7, 2009
    2,498
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    Define how much current. That determines what kind of circuit you need.
     
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