This circuit is from old American documentation, using a regulator integrated circuit that is uncommon today. The diodes can be 1N4002 and the transformer has a 500mA secondary.
This circuit was found in an American publication called Ham Radio. The circuit uses still current...
From an audio signal, this circuit gets two signals of the same amplitude and opposite phases....
Found in an Electronic Design from 1968 this circuit generates a linear sawtooth signal modulated...