Found in an Electronics Now from the 90s, this circuit appears elsewhere in this section and website. The diodes are for general use and the basic frequency is given by C.
This circuit, from a documentation of the 90s, uses unusual operations today, but the...
This circuit is from a Radio Electronics from May 1994. In it we have the way to connect three 4017...
This circuit is from the 70's by A. Fanzeres. We kept the original text. It has already been said...