Suggested by General Electric in a 1965 document, this circuit can accept a greater number of sensors. When anyone opens the SCR it fires powering the load.
This useful inductance bridge was found in a Radio Electronics from September 1963. The...
This circuit is a handset receiver that picks up the signal emitted by a coil under the rug or...
This circuit found in the October 1975 issue of Radio Electronics magazine uses an integrated...