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.
In the original application of this circuit, from a 1985 documentation, we have only two entries....
This circuit, found in Texas Instruments documentation from the 90's, provides a voltage reference of...
We found this circuit in a 1982 publication. This source allows an adjustment of the output...