This telegraph monitor was found in an American documentation for radio amateurs from the 1970s. The indicator is a common 1 mA full-scale milliammeter.
This is one of the first radios with an integrated circuit. The circuit is from a Radio...
This circuit already incorporates the amplification stage, since the oscillator is of the type of...
Output stages driving relays or other loads are plugged to the outputs of a 4017. The trigger...