Hall Effect sensors are devices which measure the direction and intensity of a magnetic field by way of its interactions with current. The Hall Effect that it observes has been known for hundreds of years, but has only been put to use in the last three decades through these sensors. Although the Hall Effect sensor is a magnetic field sensor, it can be used as the principle component in many other types of sensing devices such as those that measure current, temperature, pressure, and more. Hall Effect sensors are particularly ideal sensors because they are able to detect the voltage of a current without breaking the line to put a meter in. Rather, they can register a magnetic field from a short distance away from the conductive material. As such, they have found a continuous role in many aircraft systems such as keyboard switches, fuel-level indicators, DC transformers, and more.