This circuit is from a 1992 publication and is based on CMOS technology. The circuit is powered by a 6 V source and the displays are of common cathode.
This is a high efficiency version with the MC723 which is the Motorola version for this well-known...
This circuit was found in the March 1997 Electronics Now magazine. It uses a common analog...
This circuit is from an 80's documentation. It makes use of two SCRs with current capacity...