This circuit from General Electric was found in a 1967 documentation. The SCR is of the time, as are the transistors, but equivalents can be used.
This charger sources currents in three ranges: 10 mA, 25 mA and 50 mA; Current is sellected...
The LM11 is a precision operational amplifier from National Semiconductor. The circuit was found in...
This amplifier uses germanium transistors of the time. The circuit is from a documentation from...