In article ,
ian field wrote:
A good clue as to whether its a piezo sounder is that some other
component would provide a DC path for the collector of the driver
transistor - maybe an inductor or just a resistor if its a real
cheapie.

Isn't it easier just to look at it? A piezo sounder looks nothing like a
moving coil speaker.

--
*Why is it called tourist season if we can't shoot at them?

Dave Plowman London SW
To e-mail, change noise into sound.