This analog tachometer was found in Radio Electronics from the 90s. The components used can still be found with some ease.
The arranjment sohon Bellow, and simulated in the Multisim Blue allows to see in the oscloscope...
Found in a 90s Maxim's documentation, this circuit employs three company components and is...
This circuit was found in a 1968’s publication and uses germanium transistors. Equivalents can be...