It actually consists of a tunable field strength meter. The circuit is of an old documentation and the circuit must be tuned to the frequency to be monitored. The circuit offers the option to use a headset.
This circuit is from a 1998 Electronics Now and can be easily assembled since it uses a common...
This circuit triggers three incandescent light bulbs following the audio signal applied to its...
This circuit was obtained in the SGS manual of linear integrated circuits of 1982. The components used...