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 circuit is based on an old Siemens integrated that can now be found very easily. It allows the...
This circuit, which operates between 7 and 30 MHz, was found in Radio Electronics from the 1980s....
Found in a 1960s RCA documentation, this circuit applies to most common triacs. The trigger device is a...