9V Regulator

Ramon · Post by **Ramon** » Sun Mar 04, 2007 1:45 am

I have some batteries that are above 9V and my circuit needs 9V. I need ways to regulate the batteries to 9V. I tried finding a 9V regulator but all I can find is a -9V regulator. Then I saw the circuit to reverse the polarity of a power source. Could I simply reverse the polarity of my batteries, regulate it with the -9V regulator and then reverse it again?

Post by **Skyone** » Sun Mar 04, 2007 1:54 am

Check ti.com or digikey.com. What's your input voltage?

Ramon · Post by **Ramon** » Sun Mar 04, 2007 2:34 am

I'll be inputting 14.4V...

Oh yeah... I can't order online...

atari2600a · Post by **atari2600a** » Sun Mar 04, 2007 2:36 am

Doesn't Radio Shack sell 7809 regulators?

EDIT: 14.4V, that's over 5 volts for a reg to be burning off, which means you'll be dealing w/ a lot of heat! Make sure you get a heatsink for it.

Ramon · Post by **Ramon** » Sun Mar 04, 2007 2:38 am

Aren't 7809s the -9V regulators?

And oh yeah... I forgot... ... again...

I don't live in the US nor in Europe.

atari2600a · Post by **atari2600a** » Sun Mar 04, 2007 8:02 am

No...or at least I don't believe so...

jeroen · Post by **jeroen** » Sun Mar 04, 2007 8:12 am

I believe there was a way to get higer voltages out of 7805's. I'll look for it. I believe it was posted on bic's site.

lifeisbetterwithketchup · Sun Mar 04, 2007 8:19 am

7809 = 9v
7909 = -9v

vskid · Post by **vskid** » Sun Mar 04, 2007 8:21 am

Ramon wrote:Aren't 7809s the -9V regulators?

And oh yeah... I forgot... ... again...

I don't live in the US nor in Europe.

7909's are the -9v regulators, IIRC.
Heres bic's tutorial to get 8v out of them, the link at the bottom of the page tells you how to get other voltages.

EDIT: Dang you ketchup!

Post by **bicostp** » Sun Mar 04, 2007 9:04 am

Here's how to get 8 volts out of a 7805 using resistors. By swapping out the 220 resistor with a 330 you should get 9 volts.

<img src="http://bicostp.portablesofdoom.org/Arti ... iagram.gif">

http://bicostp.portablesofdoom.org/Articles/8v7805/

Ramon · Post by **Ramon** » Mon Mar 05, 2007 6:37 am

Oh...

It's either I have bad eyesight or a lazy reader in product lists.

Thanks, everyone.