[sdiy] Inverting amplifier for DC?

[Jeff Farr]

I should first mention that I'm a novice as well, so take this with a
grain of salt.  IIRC the Rin for an inverting amp is simply the value
of the feedback resistor, in your case 33ohms.... thats LOW. 
Depending on what your doing this for, this could certianly be *a*
problem, perhaps not this specific problem tho.

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)
>
>