This circuit was found in the May 1982 issue of Radio Electronics magazine. The circuit inverts the polarity of a power supply to obtain a voltage of -5 V.
We found this circuit in an old American documentation from the 70s. The Triac can be of any type...
The quadrature oscillator is another type of phase shift oscillator, where each of the three...
This low frequency signal converter was found in the July 1983 issue of Radio Electronics...