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 circuit works directly connected to the network and special care must be taken with its...
This circuit was found in a 1980s documentation. The IC is the 7400 and should be powered with 5...
Used by the police this receiver tuned to the low VHF band. The circuit is from a documentation from the...