Re: How this circuit works?

John Fields wrote:

The 155kHz signal from the oscillator is being rectified and smoothed,
and then if the resultant DC rises to Vcc/2, the output of the second
comparator will go high and supply DC to the piezo buzzer, which has a
built in oscillator used to drive the piezo transducer.


JF

I reckon at a pinch a couple of 555's or a 556 could be used to do the
same !

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Best Regards:
Baron.
.