This TTL circuit was found in a 1978 technical documentation. The power must be supplied with 5 V. It converts ASCII characters to hexadecimal.
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...