This TTL circuit uses LED indicators and must be powered by a voltage of 5 V. The capacitor determines the speed of the draw. We found it in documentation from the 90s.
This low power circuit can be powered with voltages from 1.8 V. We find it in a 80s Hands On...
This simple unijunction and bipolar generator appeared in Radio Electronics magazine in September 1865....
This circuit was obtained from an old American documentation having a limited adjustment range....