This circuit was found in the December 1977 issue of Radio Electronics magazine. The 4-digit circuit is based on TTL logic and must be powered by a voltage of 5 V.
This circuit was found in a 80s American documentation. The zener diodes determine the points of...
This circuit is from an old manual, but can be easily assembled as the integrated one is still...
In fact, the 556 consists of a double 555, which can be replaced by these integrated ones. The...