Metal Detector (CB21929E)

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

Ignition Switch Alarm Oscillator (CB15049E)
This circuit was found in an American publication from the 1980s. The transistor can be the BD135...
Pocket Receiver (CB23692E)
This simple two-transistor receiver was found in Radio Electronics magazine from September 1960....
LM386 0.3 W to 1 W amplifier (CB10897E)
The traditional circuit was taken from a French magazine Radio Plans that no longer exists but can...