This LC oscillator was found in English documentation from the 1990s. JFETs may be general-purpose equivalents.
This simple circuit is from a Radio Electronics from August 1952. The current depends on the...
This circuit was found in volume 5 of the 1995 Encyclopedia of Electronic Circuits. The circuit is based...
This 80's circuit can be made with current comparators. Rectification accuracy is 1% DC up to 100...