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.
This amplifier for a sinusoidal function generator uses a 741 integrated circuit. The circuit is...
This circuit is from Motorola's Linear Interface ICs of 1993. The circuit can be powered by...
This circuit is from 2005 documentation. It automatically starts an irrigation pump when the...