Metal Detector (CB21929E)

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

Optical tachometer (CB9349E)
We found this circuit in a 1970 publication by General Electric. The components can be changed...
Symmetrical 15 V Power Supply (CB19622E)
This source is used to supply circuits with operational amplifiers, being originally created for...
Crystal divider by 10 (CB6831E)
Suggested by American documentation from 1968, this circuit divides the frequency of synchronized...