This circuit was found in a 1977 documentation. With it we have the direct indication, through LEDs of an ASCII signal. The circuit must be powered by a voltage of 5 V.
This transmitter was found in an old publication on espionage. It applies a signal of a few...
This Motorola circuit uses only one transistor. The circuit is from 1965 documentation. The...
This circuit is from a Poptronics, American magazine of August 2000. The circuit can be assembled with...