The piezoelectric speaker consists of a piezoelectric crystal
connected to a metal membrane.
Buildup:
______________________
|______________________| Membrane
|##############| piezoelectric crystal
"""""""""""""" electrode
The other surface of the crystal is metalized to create
an electrode. The membrane also serves as an electrode
When a signal source is connected to the electrodes
the crystal expands and contracts in relation
to the signal, this makes the membrane vibrate and
thus creates soundwaves.
The piezoelectric speaker is compact, only about 1mm thick
but is best suited for higher frequencies. They are
used in electronic alarm clocks, buzzers and other applications
where a small soundsource is needed.
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