This tachometer and dwell meter for old cars was found in a 1975 documentation. The circuit is a reference for those who want to recover or maintain an old car.
Found in an American publication from the 1980s, this circuit can be found in commercial sound...
The circuit presented is quite interesting due to the low-pass filter using the integrated circuit...
This circuit was obtained in a 1991 Electronics Handbook. The publication no longer exists, but...