The frequency of this circuit can be varied from zero. The circuit uses the CMOS 4046 and was found in the November 1984 issue of Radio Electronics magazine. The base frequency is given by C1.
This circuit is given in two versions, having been found in a publication from the 90s. The second...
This circuit was found in an ancient American documentation. Used integrated circuits are uncommon...
This Texas Instruments circuit uses a phototransistor to fire a TTL trigger port. Other...