On Wed, 4 Nov 1998, Paul B. Webster VK2BZC wrote:

> Peter L. Peres wrote:
>
> > Schematic to work with LM324/LM358:
>
>   Peter, that circuit makes no sense at all!  You are using a voltage-
> follower with no gain to buffer a signal whose impedance is a few
> hundredths of an ohm!  Total waste of time!

That is correct, however it was to clarify the idea. The notes explain
why the amp is not used as is but as an amplifier and low pass filter.

Peter

>   If OTOH you were to provide a *gain* in the op-amp, say 500 times, to
> limit and drive a logic gate, it would be useful.

The amp already limits, depending on offset vs. input signal the output
will be rectified or clipped. You don't really need to amplify, just
remove the feedback connection. If the offset is the wrong way swap the +
and - inputs. ;) This yields Vdd size pulses at the output but you need to
low-pass in software.

Peter