This circuit was found in a documentation for radio amateurs from the year 70. Its purpose is to produce a tone on a transducer when transmitting messages in SSB telegraphy.
This circuit with analog indicator and diode bridge was found in Radio Electronics magazine from...
This is the typical audio amplifier for a 1967 television. We found it in a magazine from the...
This 4013 bistable has only a touch sensor that turns the controlled load on and off at its...