This circuit uses an unusual sensor nowadays, but the configuration can be adapted to more modern types, as well as the operational amplifier. The circuit is from an 80's documentation.
We found this circuit in a 1976 FET documentation. The circuit can be used to oscillate at other...
This oscillator generates a 1 kHz signal, using an old germanium PNP transistor. The circuit was...
We found this circuit in a European publication from the 1980s. The circuit uses germanium...