Leak Detector (CB22456E)

We found this circuit in a Popular Electronics from 1992. The transistor is general purpose, assuming equivalent.

Security Alarm (CB4866E)
This sophisticated alarm with traditional components was found in an ancient American...
FCS 8100 Clock Module (CB24495E)
This circuit is from a Fairchild digital clock module shown in the March 1977 issue of Radio...
Audio Booster 500 mW LM380 (CB13759E)
This circuit was obtained in a Radio Shack documentation from 1977. It can be used as a multimedia...