This circuit allows the activation of a remote telephone bell made with a common piezoelectric capsule. The circuit does not need power, as it is powered by the line call signal itself.
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...