| 摘要 |
Piezoelectric buzzer which can be fitted to the electrical supply mains, of the type comprising: - a buzzer 10 consisting of a piezoelectric ceramic disc 1, of a metal disc 2 placed against the said ceramic disc 1; - a drive circuit 3 for the buzzer 10; - at least two connection elements, characterised in that it comprises, between the two terminals 4 and 7 of the electrical supply mains, at least one resistor 11 and a diode 6 in series with the drive circuit 3 and the buzzer 10; and in that the assembly constituted by the buzzer 10, the drive circuit 3 and the diode 6 is short-circuited by a second diode 9, mounted inversely with respect to the first diode 6. <IMAGE>
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