12V from 9v source??

[ejbasses]

hey guys can i get more than 12V from a 9V source?

Please i need help quick!!!!!!

[Aurin]

You can increase voltage with step up transformers....

You might not be able to find a 4 to 3 ratio transformer, you might ... I don't know... But for increasing voltages step up transformers are the way to go.

[Mark Hammer]

Another route is to use voltage multipliers.  You can see an example here:  http://paia.com/fantusch.gif

The voltage multiplier is the 4049-based clock circuit in the upper right.  If the 4049 circuit was powered by 9v instead of 15, and you tapped the "ladder" at the junction of D6 and C9 (omitting the stuff to the right), you'd likely have more than needed to regulate down to 12vdc with a 3-pin regulator.

[Fp-www.Tonepad.com]

AC or DC?

Fp

[ejbasses]

FP. DC man

mark. that looks like it would work. i need something i can fit in a small package. can i get a better looking copy of that schem? please? 

[Fp-www.Tonepad.com]

Mar, That'll work but for very low currents requirements, and it's quite a circuit. Also, it's an oscilator, in the heart of that is an oscilator that makes some sort of 'ac' that is then multiplied by that ladder (as you would with 'real' AC)... SO, it's possible that if not done right it could be noisy.

When it's AC you can do the transformer thing. NOT with DC.

Fp

[The Tone God]

If the origianl supply is DC then transformers are out. There are a few ways to generate higher DC voltages.

1. The "ladder" system. Old, typically noisy, poor efficiency, low current. I wouldn't recommend this in just about every situation.

2. Charge pumps like 1044, 7660, etc. Simple, ok efficiency, limited current (typically < 100ma).

3. Switching supply. More complex, better efficiency (nearing that of transformers when done properly), usually has alot of current output options.

Lacking more information on the OPs needs I cannot recommend a course. How much current is needed ? Is this a bipolar 12v supply ? Is the 12v to be distributed amongst more then one effect ?

Andrew

[Hal]

charge pump to regulator will be the simplest.  Also semi expsnsive and very ineffecent though.

[Paul Perry (Frostwave)]

It isn't possible to reply to this, unless one knows how much current is required approximately (or what device is being supplied with the 12V).