Complex reflex receiver (T1663E)

Found in documentation from 1924, this 4-tube circuit has a heterodyne amplifier, as it was called.

| Clique na imagem para ampliar |

Soldering Iron LED Indicator (CB17055E)
This simple indicator circuit, in two versions, was found in a 1997 documentation. In the original...
Electronic Potentiometer (CB15705E)
The circuit illustrated in the figure can be used to control the speed of small DC motors or the...
Animatronic with speed adjustment (CB20430E)
This is an improved version of the previous circuit that includes speed control. The engine can be...