We found this circuit in the March 1992 issue of Radio Electronics magazine. The circuit has a range from 1.25 V to 1 kV. The formula for the voltage values is given.
This oscillator circuit is from a Radio Electronics magazine from September 1960. The frequency depends...
This circuit uses a piezoelectric tweeter to emit a powerful continuous sound above the audible...
Found in an English documentation from the 90's, this circuit makes slow logical pulses audible,...