This circuit operates from 25 to 65 kHz depending on the transducer used and the settings. We found it in the Radio Electronics magazine of July 1985. The 9V to 12V power supply is not given.
Found in a 1969 neon lamp publication, this circuit provides two voltages under very-low currents....
This basic circuit for a common phototransistor was found in an Electronics Now from the 90s. The...
Based on the frequency of the power grid, this circuit produces square signals for use in digital...