This 1967 General Electric circuit makes use of an array of 3 (integrated) transistors for an amplifier stage. The circuit has a 500 mV output.
This step-down converter with 10 to 60 V input produces a 5 V output with a maximum current of 5...
Found in an old American documentation, this step has as input and output transformers coupling. Two...
This circuit was found in a 1963 magazine, but can still be easily assembled with some current...