Period to voltage converter (CB8869E)

This circuit was found in a 1969 EEE. The circuit uses transistors from the era that can be replaced by modern equivalents.

| Clique na imagem para ampliar |

Regulator with emitter follower (CB8811E)
Found in a 1966’s General Electric documentation, this circuit uses a triple diode from the time....
Car 9 V adapter (CB8956E)
Found in documentation from the 1990s, this circuit converts 12 V to 9 V from a car's power...
Simple Ohmmeter (CB11932E)
This ohmmeter can be made with a scrap milliammeter used for continuity tests or even resistance...