Using the 741 this circuit can be adjusted to values between 1 Hz and 100 kHz. The power supply must be symmetrical. We found it in the Radio Electronics magazine of November 1973.
This Nixie pipe circuit was found in 1965 documentation. Note the high supply voltage. Appropriate...
This circuit is from a 1976 publication, but it can be assembled with modern components. For the...
Found in Popular Electronics from the 90's, this circuit consists of an audio oscillator for Morse...