This circuit uses an unusual PLL, the 4046 CMOS. We found it in the October 1994 issue of Electronics Now. The circuit also uses a 4093 gate as a trigger.
This circuit is from a 1991 publication. It produces a constant current controlled by the input...
This circuit uses two sensors that are placed at the intersection of a miniature railroad, causing the LED...
Found in a 90's EDN, this circuit can be used as a shield. The components depend on the MOSFETs...