This circuit also appears elsewhere on this site, obtained from other sources. This is an 80's American schematic book. Instead the lamp can be used white high-brightness LEDs.
This circuit is from an old American documentation using LEDs in the rectification. The circuit...
This source only uses passive components (without transistors or integrated circuits) and even so it...
This four-digit circuit was found in a 1990 documentation. The sensor can be a contact or reed...