200 mW Amplifier (CB21672E)

This amplifier was taken from documentation from the 1960s. Transistors are germanium types from the time. Note the simple regulated power supply.

Differential Amplifier (CB6546E)
This circuit was found in an American publication from 1968. The transistors are from the time,...
Tone Control Preamplifier (CB18561E)
This preamp with several inputs using germanium transistors from the time was found in Japanese...
Crossing Signal for Railroad Modeling (CB3854E)
This circuit uses two sensors that are placed at the intersection of a miniature railway, causing...