[sdiy] a bit frustrated

[Theo]

That is easy.
Set two 9V batteries in series, the connection between the two batteries
becomes the 0V (gnd).
Now the positive side is +9V and the negative side is -9V

The other way is using only one battery and set two 1meg resistors in series
between the + and - connections.
Next connect an opamp buffer ( + input = in and - input to output) to the
point between the two resistors.
The output of the opamp buffer is now your 0V (gnd)
So you have a +4.5V, gnd and -4,5V supply.

Hope this helps,
Theo

------------------
----- Original Message -----
From: <ElmacacoX at aol.com>
To: <xoxos at earthlink.net>; <synth-diy at node12b53.a2000.nl>
Sent: Thursday, May 10, 2001 4:27 AM
Subject: Re: [sdiy] a bit frustrated


> OK, I'm new at this too, but I think I know what's wrong.  Op amps need a
> symetrical powersupply,  you need, say 9v+ on the + of the TL082, and 9V-
on
> the negtive input, not ground.  this is why it isn't working I reckon.
now
> you'll need the other guy's with the EE degrees to tell you how to build a
> symetrical psu that runs off 9v batteries.
>
> don't dispair, it is worth the effort and frustration in the end.... I
> think....
>
> eduardo
>