Paraphase amplifier (T389E)

This 6C5 tube circuit was found in a modern tube design manual. The circuit applies to other equivalent triodes.

Darlington photo relay (CB8315E)
Found in Ferranti's 1968 documentation, this circuit uses a Darlington photo transistor to drive a...
Light level control (CB20718E)
Found in documentation from the 70s, this circuit uses components from that time. Some of these...
Battery Monitor (CB15080E)
This circuit monitors the state of a 12 V battery and can be used directly with one, or even in a...