This circuit from an old MIT documentation excites an oscillograph element, an old waveform viewer.
The integrated circuits used in this 1989 project are uncommon today, including the IF coil that...
Figure Bellow shows how to use a 7490 (TTL) IC to divide the frequency of a TTL signal by 6; The...
This circuit uses an operational that is not currently common. We found it in an old American...