Adjustable reference (CB21539E)

This circuit was obtained from an old American publication. The uA702 is a differential amplifier and the diode is a zener.

Battery Charger (CB4388E)
This circuit, obtained from a 1965 magazine, can still be assembled using some modern equivalent...
Full wave power supply (CB22340E)
This source was obtained from a book on transistors from the 60's. The circuit uses germanium...
40W Voltage Inverter (CB25375E)
This powerful inverter provides a high-quality sine wave signal. I found it in a Radio Electronics issue...