[sdiy] Inverting an envelope?

[Veronica Merryfield]

Op-amp, gain of -1? 

On 2011-05-21, at 11:37 PM, James Coplin wrote:

> What is the best (hopefully also easiest) way to invert an envelope?  I'm
> finally getting around to racking up my SEMs and I wanted to add negative
> versions of the two envelopes.  I don't want to invert the shape in the
> positive voltage range but mirror it in the negative range. In other
> words, instead of going from 0v to 10v and back to 0v, to go from 0v to
> -10v back to 0v.  Thoughts?
> 
> James R. Coplin
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