[sdiy] Simple circuit challenge: |a-b|

Neil Harper metadata at gmx.com
Fri Mar 22 00:28:59 CET 2024

On 2024-03-21 19:14, Neil Harper via Synth-diy wrote:
> On 2024-03-21 15:50, Rutger Vlek via Synth-diy wrote:> Dear list,
>  >
>  > while hobbying on an experimental design, I'm looking for a simple
>  > analog circuit to give me the absolute value of the difference between
>  > two signals (mathematically written as |a-b|).
> can't you just put one signal into the inverting input of an op-amp and
> the other signal into the non-inverting op-amp?
> if loading the signals are an issue, you can do op-amp buffers before it
> and I think that configuration is called a "differential amp" and uses 3
> op-amp cells. there's also dedicated IC's for diff amps, but they can be
> $8-12 each and I think are only used when crazy precision is necessary -
> maybe because it reduces the cumulative effects of resistor tolerance in
> the 3 op-amp version?
> --
> /// Neil Harper
> /// Every Wave is New Until it Breaks

forget what I said, i didn't see the absolute value thing. i blame the
internet for stealing my ability to fully read things.

/// Neil Harper
/// Every Wave is New Until it Breaks

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