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 can operate with 5 uV to 1 mV input signals from low impedance sources such as...
This very simple circuit with neon lamps indicates who pressed the button first, lighting the...
This circuit was originally designed for the practice of Morse code, something common in 1966, the year...