Found in a 1964 General Electric documentation, this circuit uses PUTs that are not currently common components. By changing the capacitors, the frequency can be changed.
This circuit is from an old documentation but still current for assembly. Just use BC548 instead...
This circuit was found in the November 1993 issue of Electronics Now magazine. The two-stage...
This amplifier in common mode was obtained in an Electronic Design from the 90's. The circuit is...