This National Semiconductor circuit appears elsewhere on this site. The circuit must be powered by symmetrical source and equivalent modern operational can be used.
This circuit was found in an English magazine from 1978, but it is still current, just change the...
We found this circuit in a Radio Electronics from October 1976. The components are still common, but...
Found in an old Elektor, this circuit uses two 7-segment displays to indicate the volume of an...