This wide-range radiation monitor was found in a 1980s documentation. The circuit uses a diode as a sensor and is quite critical requiring shielding shown in dashes to prevent snoring due to gain.
This circuit produces the sound of percussion such as blocks, drum, bell, etc. The frequency...
We found this oscillator in a publication from the 1960s. The frequency is around 600 Hz with the...
Found in a Popular Electronics from 1992, this circuit uses a PLL567 in an audio meter bridge that...