Found in a 1992 book, this circuit is intended for operation with audio signals. Equivalent operational amplifiers can be used. The optical coupler is an unusual type today.
Two inverters of a 4069B type CMOS integrated circuit form this oscillator which is characterized by having...
Raytheon's used operational amplifier is rare today, but the configuration can be adapted to use...
Found in a radio amateur magazine of the 1980s, this circuit uses components that can still be...