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 in a 1960 Sylvania manual, this circuit is intended to measure audio signals frequency....
We found this circuit for vocal effects in the September 1990 issue of Radio Electronics magazine. The...
Depending on the output transistor used, this transmitter can provide power from 1 to 3 W. The...