This circuit was found in a 1970s General Electric documentation. This circuit already used an emitting LED. The circuit operates at frequencies from 50 Hz to 50 kHz with short pulses
This circuit was obtained in an old American documentation, remembering that the 566 is the double...
With this simple circuit it is possible to simulate a telephone line for carrying out repairs on...
This simple circuit was found in a 1981 publication. As readers can see, we have an H switch and...