SCR Rain or Leak Alarm (CB22097E)

This sensitive circuit was found in old documentation. The SCR can be any of the 106 series and the transistor a BC548.

Shield with 7481 (CB24730E)
This relay shield circuit for old computers was found in January 1983 Radio Electronics magazine. The...
Magnetic Field Detector (CB11226E)
This circuit detects magnetic fields by approximation, using a Hall sensor. The components are...
5-Range Voltmeter with AC to DC Converter (CB25224E)
This digital instrument input circuit was found in the September 1989 issue of Radio Electronics...