Re: How this circuit works?

> Right there in the text "The left side of the circuit uses a low-power
> dual comparator (MAX9022) to form a relaxation oscillator..."
>
> So, (a) you've been _told_ what's going on, and (b) it's not an op-amp,
> it's a comparator.

OK, this is clear now, shame engineers use the same symbols for
different things...

>
> On the right side of the circuit, consider what happens when a bunch of
> AC shows up on the open end of C4.

This is still not understood. The text talks about 155KHz, which is
more
than the human ear can hear, so which AC are we talking about?
And even if we could hear 155KHz, D3 and C5 for a rectifier which
converts any ac to dc, so how can a dc signal vibrate the piezo?

>
> --
>
> Tim Wescott
> Wescott Design Services
> http://www.wescottdesign.com
>
> Do you need to implement control loops in software?
> "Applied Control Theory for Embedded Systems" gives you just what it
says.
> See details at http://www.wescottdesign.com/actfes/actfes.html