This circuit was found in a 1977 timer cookbook. The circuit can generate signals with up to 99% active cycle. The FET can be BF245 or MPF102 and the basic frequency given by R1, R2 and C1.
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...