1940s commercial receiver (T1618E)

This receiver was found in a Radio Electronics from 1949. It is a superheterodyne of the time using 6 tubes.

Crossing Signal for Railroad Modeling (CB3854E)
This circuit uses two sensors that are placed at the intersection of a miniature railway, causing...
Headphone amplifier (CB7100E)
This high impedance headphone amplifier was found in American documentation from the 1990s. Any...
Three Tone Oscillator (CB418)
This circuit uses one UJT (Unijunction Transistor) to produce three different tones in a...