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 circuit is from 1987 documentation. The original project was carried out with the tape...
This traditional crystal radio circuit, but which has a modern version with diode, was found in an...
This VCA was found in the July 1988 issue of Radio Electronics magazine. It uses an OTA op amp and...