This circuit was found in a 90s Wels' Think Tank. The frequency depends on C2 and R3. The handset or speaker must be at least 80-ohm. Observe the low supply voltage.
This configuration uses the 4 gates of a 7401 integrated circuit. The capacitors determine the...
We found this circuit in a documentation from the 70s. The original text was kept. The oscillator...
This circuit was found in the September 1974 issue of Radio Electronics magazine. It consists of a...