This is a typical 3 ½ digit TTL counter. We found it in the September 1973 issue of Radio Electronics magazine. The circuit is to be powered by 5 V. It can be expanded to more digits.
This circuit was obtained in a magazine for radio amateurs 73 of the 90s. The circuit is based on...
This circuit is from a documentation on the MC1539 from Motorola and may, however, be implemented...