This dual-LED circuit indicates three signal levels. It was found in the January 1996 issue of Electronics Now magazine. The integrated circuit may be an LM339 or another comparator.
This type of circuit and with this integrated circuit appears several times on this website. The...
Using transistors of the time, this circuit was published in Radio Electronics magazine in...
The integrated circuit used in this 1982 project is not very common today. It can be adapted to...