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 photometer is based on a Wheatstone bridge that must be balanced by the linear potentiometer P1. The...
This circuit also appears elsewhere on this site, obtained from other sources. This is an 80's...
This circuit is from a 90s Popular Electronics. The circuit employs a ZN461E that is not a common...