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.
We found this circuit in an old documentation for hams. In it we have the way to use a varicap to...
This circuit is part of an article published in the March 1990 issue of Radio Electronics...
) Other operational amplifiers series, such as the MC34072, MC34074, MC35071, MC35072, MC35074 or...