This circuit uses a PLL4046 oscillator to excite a piezoelectric ceramic. The circuit is from an October 1994 Electronics Now magazine.
This circuit is from an English magazine of 1977. The circuit is still current, just using BC547...
This circuit was obtained in an old Elektor. It is a reference, since the integrated products of the...
This circuit was found in a European technical documentation from 1991. It is a circuit that must...