This circuit is used in transceivers, enabling input selection by diode switching through polarity reversal. The circuit is from an old American documentation on telecommunications.
Found on Popular Electronics this circuit has variations found throughout this site and section....
The search coil of this detector consists of 140 turns of wire 18 in an 8 inch diameter form. The...
This circuit was found in an English publication from 1967. The circuit is for listening on a...