We found this circuit in a magazine 73 from the 90's. It is a circuit indicated for radio-amateur transmitters with the frequencies determined by the sets of coils.
This circuit was found in an American documentation and can be added to common amplifiers of any...
This circuit reinforces signals in a frequency range between 1500 and 2000 Hz for use in...
This simple circuit indicates, through an LED, when the water level of a filter (or other kind of...