This circuit was found in a 1968 General Electric documentation. It has an input impedance of 2 M ohms and excites a load of 16 ohms. The integrated circuit of the time is the PA237.
Texas Instruments' low power operational amplifiers OPAx196 can be found on Mouser Electronics....
This variable power supply uses common components and can supply a current up to 1 A. The...
This circuit was fond in an old publication of the years 1950. The transistors are germanium types and...