[sdiy] Re: Inverting amplifier for DC?

[Amos]

Disregard my question please... my first email was lost in cyberspace for
three days and I have solved the problem since then, in a much simpler
fashion.  No credit to me and all to the person who suggested that a simple
2n3906 transistor and three resistors would do the trick -- it does,
excellently.  And now my x0xb0x (actually Rui Peixoto's) has an Accent gate
CV input.  joy!

Kind regards,

Amos

On 11/26/05, Amos <controlvoltage at gmail.com> wrote:
>
> Help, O knowledgeable ones!
>
> I have a very simple question.
>
> I have done a lot of repair work but very little modification or custom
> work thus far.
>
> I am now trying to do a trivial thing and need some help with
> troubleshooting...
>
> I want to take a +5V gate signal in and get -5VDC out when it triggers.
> So, I figured an inverting unity-gain amplifier would solve my problem.
>
> I have built the standard textbook inverting amp, using half of an RC4558
> opamp IC
> it doesn't seem to be inverting... output == input, more or less.
>
> input and feedback resistor are both 33 ohm
> input is to negative (inverting) in, feedback is from output to inverting
> input.
> non-inverting input is grounded.  Power is +/- 12V; trigger input is ~5V.
>
> Is the "textbook" circuit too simple; is there more I should be doing?
> What's up?
>
> Thanks for any help....
>
> -Amos (accentuating the negative)
>
>
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