Piezoelectric acoustic alarm
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United States of America Patent
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Apr 1, 2003
Grant Date -
N/A
app pub date -
Jun 3, 2002
filing date -
Jul 23, 1999
priority date (Note) -
Expired
status (Latency Note)
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Abstract
In a piezoelectric acoustic alarm piezoelements (2a, 2b) each excited by a square-wave voltage are arranged opposite each other in a resonance cavity (1) and each oscillate in opposing directions. The two square-wave voltages (V.sub.a, V.sub.b) controlled by a microprocessor (8) are phase displaced by a square-wave pulse length and are positive or negative. A piezo-sound source designed and excited in this way is characterised by a high sound volume with low current consumption and small size.
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