Today this frequency corresponds to the end of the FM band. However, in December 1958, when the circuit was published in Radio Electronics magazine it was the frequency used by American satellites.
This 2003 circuit uses two types of sensors: by reed-switch and by infrared. If the magnetic...
This one transistor stage for audio signals was found in an old publication of the year 1958. The...
Using the four amplifiers of an LM324 this circuit was found in the June 1996 issue of Electronics Now...