Using 9V battery to power a +/- 8V chip?

Discussion in 'General Electronics Chat' started by Rogare, Mar 20, 2012.

  1. Rogare

    Thread Starter Member

    Mar 9, 2012
    Hello, I need to power a chip that requires +/- 8–18V. Is this possible to do with a single 9 V? (I'm guessing not.)

    If not, could I connect two 9V batteries in series, as shown below?

    -|-------- | ---------|
    |+ 9V –| --- |+ 9V –|

    In the diagram, I'm pulling the positive supply from the positive end of the two connected batteries, the negative supply from the other end, and the ground from between the two.

    Thanks for reading.
  2. vpoko


    Jan 5, 2012
    You're 100% right, wiring the batteries in series and using the middle terminal as a ground will give you both +9 (from the positive terminal) and -9 (from the negative terminal). It cannot be done with a single battery.
    Rogare likes this.
  3. Rogare

    Thread Starter Member

    Mar 9, 2012
    OK, thanks for verifying!
  4. Stuntman

    Active Member

    Mar 28, 2011
    In an effort to be thorough, I will add:

    Yes, conventionally, vpoko is correct. There is no wire orientation that will allow you the >9 potential difference you require.

    However, for the sake of "is this possible", consider if you were to use that 9v battery with a boost converter such as:

    This would now provide you with a potential difference greater than 9V, let's say it is set up to give you a 20V output. Now all you need to do is setup a virtual ground (which is what you did with your two battery scheme) which would then provide a +/- 10V supply. This website should give you all the details you want:

    I'm not saying this is easy or economical, but to answer your question, yes, it is possible.
    Rogare and vpoko like this.
  5. Rogare

    Thread Starter Member

    Mar 9, 2012
    That's good to know, thanks Stuntman!
  6. jimkeith

    Active Member

    Oct 26, 2011
    I have used this chip with good success to generate a negative voltage.
  7. Rogare

    Thread Starter Member

    Mar 9, 2012
  8. n1ist

    Active Member

    Mar 8, 2009
    How much current do you need? If it's very low, you can use a MAX232; just tap off the V- and V+ charge pumps. I've used that in the past to power an opamp.
    Stuntman likes this.