5 kW switch (CB21370E)

Found in a 1967 GE SCR manual, this circuit is intended to control resistive loads, such as heating elements, up to 5 kW.

Coded Switch (CB16887E)
This code switch only activates a relay when the right sequence of buttons is pressed. The circuit...
Variable power supply (CB21779E)
This current-limited variable power supply was found in 1977 book. The diodes are according to...
Null indicator (CB22313E)
This circuit for measuring bridges was found in American documentation from the 60's. Transistors are...