Counter module (CB21713E)

This traditional TTL counter module was found in Internet documentation. The power supply must be 5V and the display is a common anode.

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...