Sean Breheny wrote:

> ...After all, a 1Hz signal would not excite a piezo element very well
> and it also wouldn't be very audible :) ...
>

Actually, switching a standard piezo disc (no built-in oscillator) on and off at
a 1 Hz rate is *very* audible. (However, the resulting clicks are well into the
human audible range).

Ken Pergola