This realistic circuit has longer timings for green and red lights, with shorter timings for yellow. The circuit is from an Electronics Now from May 1994.
The operational amplifier taken as an example is uncommon today, but the configuration can be made...
The integrated circuit used in this regulator is not easy to obtain, since the publication is from...
This configuration was obtained in a 1977 FET Databook. The circuit can be practically any JFET...