This circuit was found in an American documentation from 1969. Indications of the used transistors are not given, but general-purpose types can be tested.
This circuit can shift the phase of a signal from 0 to 360º. FETs admit equivalents and the...
This circuit with germanium transistors was found in a 1980s documentation. The circuit makes use...
Using components from the era, this 90's EDN circuit is used in analog to digital conversion...