Using an analog microamperimeter this circuit has a phototransistor adapted to the wheel as a sensor. The circuit is from American documentation from the 1980s, but the components are common today.
The presented circuit generates a pulse whose delay in relation to the input depends on RC. These...
This version of an astable CMOS with the 4069, and which appears elsewhere on this site and in...
This circuit, found in similar versions in other articles in this section, dynamically tests...