Metal Detector (CB21929E)

This two-transistor metal finder was found in a Raytheon manual from the 1950s. The transistors are germanium from the time.

Power Failure Alarm (CB25348E)
This circuit triggers an alarm when the mains power is cut off. The circuit was found in the July...
Tuned null indicator (CB22314E)
This acutely tuned circuit was found in American documentation from the 1960s. The transistors are germanium...
MW Transmitter (CB20809E)
This small AM transmitter was found in American documentation from the 1980s. Transistor support...