18volt bipolar power supply

[caspercody]

I need a 18volt bipolar power supply. Can I connect two 9 volt batteries together to get this? If I connect the negative of the first battery to the positive of the second battery would I end up with, +18 volts at the positive of the first battery, -18 volts at the negative of the second battery, and ground at the connection of the two batteries (the positive and negative connection mentioned earlier)?

I do have a 12 volt power supply could I use this as a bipolar power supply? It has a positive and negative lead, but no ground?

[doc_drop]

You will only get +18v by connecting 2 9v batteries in series, not a bipolar supply. The negative side is at 0v. By convention this is also called ground, but it doesn't have to be.

I believe that to get a bipolar supply you need 2 more batteries. Ground in this case is between the 2 pairs, +18v on one end and -18v on the other. But that's a lot of batteries... Please someone correct me if I am wrong.

The negative lead on a 12v supply corresponds with ground/0v.

[caspercody]

Thanks doc_drop!

Is there a circuit out there that I could get 15 to 18 volts bi polar using 9 volt batteries?

I know there is a circuit using AC power, but want to stay away from AC if possible.

[caspercody]

If I were to use Gaussmarkovs bipolar 9v power supply (based on RG Keens Max1044 circuit), and use two 9volt batteries (in series) would that work to get 18 volts bipolar output?

[caspercody]

Okay I read the data sheet on the Max1004, and it will only take max 10 volts. So, looking at RG Keens charge pump converter, I see how to get a bipolar 9 volts from a single 9 volt battery. And he also shows how to get higher voltage from a 9 volt battery.

Does anyone know if one could do both? Some how use the charge pump converter to get around 18 volts out, and as a bipolar supply from the 9 volt battery?

[isildur100]

Hi, You might want to consider a power supply like that one:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=270489613849&ssPageName=STRK:MEWAX:IT

It offers +/-24V dc. Couple that with voltage regulators to obtain +/-18V and you are all set. I have not tried one but was considering it.

Anyways, take a look.

John

[caspercody]

Looks really nice, but not bipolar.

But thanks for the information!

[jrem]

Look at a NJM2360 DC to DC converter.  Use it as a charge pump.  Once you get the output rail-to-rail desired you can split it for a bi-polar supply.

[isildur100]

Looks really nice, but not bipolar.

But thanks for the information!

Look closer, it is +/-24V, look at the picture of the device, you will see and there are + and - connectors on the thing.

[MikeH]

There's a +/- power supply project at music from outer space:

http://www.musicfromouterspace.com/analogsynth/POWERSUPPLY2009/POWERSUPPLY2009.php

edit: oh wait- that only goes to +/- 15v.  Nevermind

[caspercody]

Thanks MikeH! 15 volts is fine, I will look into this.

[caspercody]

I did find a bi polar voltage doubler using a LT1054 chip, if anyone is interested?