Hall effect and sensors
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The document discusses various methods for detecting positions of landing gear and doors using different types of sensors, including mechanical switches, reed switches, proximity switches, and hall effect sensors. It highlights the advantages of hall effect and proximity sensors over mechanical switches, such as longer lifespan and hermetic sealing. Additionally, it explains the principle of the hall effect, detailing how a magnetic field interacts with current in a semiconductor to induce a measurable voltage.
Hall effect and sensors
- 1. HALL EFFECT AND SENSORS
- 2. Switches and Sensors There are many methods to detect the positions of the surfaces such as landing gear positions or landing gear doors. The are the possible sensors/ switches. ◦ Mechanical switch actuated by linkages or the door itself. ◦ Reed switch. ◦ Proximity switch ◦ Hall effect sensor.
- 3. Mechanical Versus Electronic The mechanical switches have moving parts, which will wear off. It is effected by environmental and vibration. The proximity and hall effect sensors have to moving parts and can be hermetically sealed. ◦ These sensors can last much longer. ◦ It is easier to test the system.
- 4. Hall Effect Principle A thin sheet of semiconducting material (Hall element) through which a current is passed. The output connections are perpendicular to the direction of current. When no magnetic field is present, current distribution is uniform and no potential difference is seen across the output.
- 5. Hall Effect with magnetic field When a perpendicular magnetic field is present, a Lorentz force is exerted on the current. This force disturbs the current distribution, resulting in a potential difference (voltage) across the output. This voltage is the Hall voltage (VH). The interaction of the magnetic field and the current is shown in equation.
- 6. A Simple Sensor Take note of the elements.. ◦ Hall elements ◦ Amplifier ◦ Transistor switch The sensor will detect the target and a small voltage is induced by the Hall element. The voltage is amplified and switch the transister on.
- 7. Hall Effect Sensor used for RPM sensor
- 8. RESOURCES My Blog CAA UK Recommended Books Title Author Aircraft Electricity and Eisman 0-02-801859-1 Electronics Art of Electronics Horowitz 0-521-37095-7 Horowitz /Hill /Hill Elements of Electronics Hickey/ 0070286957 Villines Learning Modern Aviation Helfrich 0-13-118803-8 Electronics electronics- tutorials.ws/electromagnetism/ Micro Electronics in E Pallet 0-273-08612-X hall-effect.html Aircraft systems