This circuit was obtained in a 1970 EEE and applies to almost any operational amplifier. The supply voltage depends on the operational amplifiers used.
Found in a 1980s amateur radio QST magazine, this is the conventional circuit of a medium-wave...
Found in an Elektor from the 90s, this circuit makes use of current components. The input voltage...
Suggested by General Electric in a 1967 documentation, this circuit replaces the Thryraton tubes used at...