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theory:sensor_technology:st18_magnetic_sensors [2018/10/09 17:09]
glangereis ↷ Page name changed from theory:sensor_technology:st18_inductive_sensors to theory:sensor_technology:st18_magnetic_sensors
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-====== Sensors based on magnetic effects ====== 
- 
-===== Physical principles ===== 
- 
-There are several sensor types where the operation is based on magnetic principles. For example: 
-  * Magnetic sensors (Reed contacts) 
-  * Inductive sensors 
-  * Magneto-resistive sensors 
-  * Hall sensors 
-  * LVDT 
-  * Resolvers. 
- 
-How they differ depends mainly on the physical phenomenon that is behind the operation. To explain this, consider the following phenomena: 
-  - An electric current results in a magnetic field (as in a coil) 
-  - A changing magnetic field results in an electric field (as in a dynamo) 
-  - A static charge results in an electric field 
-  - A magnetic monopole does not exist 
-  - A moving charge in a magnetic field experiences a force 
-These five phenomena may relate to principles you have heard of or with which you are familiar. They are in fact equal to the four Maxwell equations: 
- 
-\begin{equation} 
-\begin{aligned} 
-\nabla\times\mathbf{H} \quad & = \quad \mathbf{J}_{f} + \frac{\partial\mathbf{D}}{\partial t} , & \quad \text{(Ampère'​s circuital law with Maxwell addition)} \\[5pt] 
-\nabla\times\mathbf{E} \quad & = \quad -\frac{\partial\mathbf{B}}{\partial t},  & \quad \text{(Faraday'​s law of induction with Maxwell addition)} ​  ​\\[5pt] 
-\nabla\cdot\mathbf{D} \quad & = \quad \rho_{f}, & \quad \text{(Gauss'​s law)}   ​\\[5pt] 
-\nabla\cdot\mathbf{B} \quad & = \quad 0  & \quad \text{(Gauss'​s law for magnetism)} 
-\end{aligned} 
-\end{equation} 
- 
-or in integral form: 
-\begin{equation} 
-\begin{aligned} 
-\oint \mathbf{H}\cdot\mathrm{d}\mathbf{l} \quad & = \quad \int_{S}\left ( \mathbf{J}_{f} + \frac{\partial\mathbf{D}}{\partial t} \right )\cdot\mathrm{d}\mathbf{S} , & \quad \text{(Ampère'​s circuital law)} \\[5pt] 
-\oint \mathbf{E}\cdot\mathrm{d}\mathbf{l} \quad & = \quad \int_{S}\left ( -\frac{\partial\mathbf{B}}{\partial t} \right )\cdot\mathrm{d}\mathbf{S} ,  & \quad \text{(Faraday'​s law of induction)} \\[5pt] 
-\oint_{S} \mathbf{D}\cdot\mathrm{d}\mathbf{S} \quad & = \quad \int_{v}\rho_{f}\mathrm{d}v , & \quad \text{(Gauss'​s law)} \\[5pt] 
-\oint_{S} \mathbf{B}\cdot\mathrm{d}\mathbf{S} \quad & = \quad 0 & \quad \text{(Gauss'​s law for magnetism)} 
-\end{aligned} 
-\end{equation} 
- 
-plus the Lorenz force law 
- 
-\begin{equation} 
-\mathbf{F}=q\left ( \mathbf{E}+\mathbf{v}\times\mathbf{B} \right ) 
-\end{equation} 
- 
-The first two laws explain the behaviour inductive sensors since they show the mutual interaction between varying magnetic and electric fields. A varying electric field generates a magnetic field, and a varying magnetic field generates an electric field. The fifth law, Lorenz´s law, is the basis of AMR and Hall sensors because it describes the behaviour of moving electrons in an magnetic field. 
- 
- 
-<​imgcaption Dia05|Dia05>​{{inductive_sensors_dia05.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia06|Dia06>​{{inductive_sensors_dia06.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia07|Dia07>​{{inductive_sensors_dia07.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia08|Dia08>​{{inductive_sensors_dia08.png?​300}}</​imgcaption>​ 
- 
-===== Magnetic sensors ===== 
-  
-<​imgcaption Dia10|Dia10>​{{inductive_sensors_dia10.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia1-03|Dia10-03>​{{inductive_sensors_dia10-03.png?​300}}</​imgcaption>​ 
- 
-===== Inductive sensors ===== 
- 
-<​imgcaption Dia12|Dia12>​{{inductive_sensors_dia12.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia12-04|Dia12-04>​{{inductive_sensors_dia12-04.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia13|Dia13>​{{inductive_sensors_dia13.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia14|Dia14>​{{inductive_sensors_dia14.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia15|Dia15>​{{inductive_sensors_dia15.png?​300}}</​imgcaption>​ 
- 
-===== Magnetoresistive sensors ===== 
- 
-<​imgcaption Dia17|Dia17>​{{inductive_sensors_dia17.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia18|Dia18>​{{inductive_sensors_dia18.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia19|Dia19>​{{inductive_sensors_dia19.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia19-05|Dia19-05>​{{inductive_sensors_dia19-05.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia20|Dia20>​{{inductive_sensors_dia20.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia21|Dia21>​{{inductive_sensors_dia21.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia22|Dia22>​{{inductive_sensors_dia22.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia23|Dia23>​{{inductive_sensors_dia23.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia24|Dia24>​{{inductive_sensors_dia24.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia25|Dia25>​{{inductive_sensors_dia25.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia26|Dia26>​{{inductive_sensors_dia26.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia27|Dia27>​{{inductive_sensors_dia27.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia28|Dia28>​{{inductive_sensors_dia28.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia29|Dia29>​{{inductive_sensors_dia29.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia30|Dia30>​{{inductive_sensors_dia30.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia31|Dia31>​{{inductive_sensors_dia31.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia32|Dia32>​{{inductive_sensors_dia32.png?​300}}</​imgcaption>​ 
- 
-===== Hall sensors ===== 
- 
-<​imgcaption Dia36|Dia36>​{{inductive_sensors_dia36.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia37|Dia37>​{{inductive_sensors_dia37.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia38|Dia38>​{{inductive_sensors_dia38.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia39|Dia39>​{{inductive_sensors_dia39.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia40|Dia40>​{{inductive_sensors_dia40.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia40-06|Dia40-06>​{{inductive_sensors_dia40-06.png?​300}}</​imgcaption>​ 
- 
-===== The Linear Variable Differential Transformer (LVDT) ===== 
- 
-<​imgcaption Dia42|Dia42>​{{inductive_sensors_dia42.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia43|Dia43>​{{inductive_sensors_dia43.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia44|Dia44>​{{inductive_sensors_dia44.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia45|Dia45>​{{inductive_sensors_dia45.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia46|Dia46>​{{inductive_sensors_dia46.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia47|Dia47>​{{inductive_sensors_dia47.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia48|Dia48>​{{inductive_sensors_dia48.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia49|Dia49>​{{inductive_sensors_dia49.png?​300}}</​imgcaption>​ 
- 
-===== Resolvers ===== 
- 
-<​imgcaption Dia51|Dia51>​{{inductive_sensors_dia51.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia52|Dia52>​{{inductive_sensors_dia52.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia53|Dia53>​{{inductive_sensors_dia53.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia54|Dia54>​{{inductive_sensors_dia54.png?​300}}</​imgcaption>​ 
-<​imgcaption Dia55-07|Dia55-07>​{{inductive_sensors_dia55-07.png?​300}}</​imgcaption>​ 
- 
-===== Summary ===== 
- 
-<​imgcaption Dia55-08|Dia55-08>​{{inductive_sensors_dia55-08.png?​300}}</​imgcaption>​ 
- 
-====== Sensor Technology TOC ====== 
- 
-These are the chapters for the Sensor Technology course: 
-  * Chapter 1: [[theory:​sensor_technology:​st1_measurement_theory|Measurement Theory]] 
-  * Chapter 2: [[theory:​sensor_technology:​st2_measurement_errors|Measurement Errors]] 
-  * Chapter 3: [[theory:​sensor_technology:​st3_measurement_technology|Measurement Technology]] 
-  * Chapter 4: [[theory:​sensor_technology:​stb_conventions_for_good_graphs_and_tables|Circuits,​ Graphs, Tables, Pictures and Code]] 
-  * Chapter 5: [[theory:​sensor_technology:​st4_sensor_theory|Basic Sensor Theory]] 
-  * Chapter 6: [[theory:​sensor_technology:​st6_sensoractuatorsystems|Sensor-Actuator Systems]] ​ 
-  * Chapter 7: [[theory:​sensor_technology:​st7_modelling_main|Modelling]] 
-  * Chapter 8: [[theory:​sensor_technology:​st8_accelerometer_model|Modelling:​ The Accelerometer]] - example of a second order system 
-  * Chapter 9: [[theory:​sensor_technology:​st9_scaling|Modelling:​ Scaling]] - why small things appear to be stiffer 
-  * Chapter 10: [[theory:​sensor_technology:​st10_lumped_element_models|Modelling:​ Lumped Element Models]] 
-  * Chapter 11: [[theory:​sensor_technology:​st11_finite_element_models|Modelling:​ Finite Element Models]] 
-  * Chapter 12: [[theory:​sensor_technology:​st12_impedance_spectroscopy|Modelling:​ Transducer Characterization by Impedance Spectroscopy]] 
-  * Chapter 13: [[theory:​sensor_technology:​st13_lumped_element_models_advanced|Modelling:​ Systems Theory]] 
-  * Chapter 14: [[theory:​sensor_technology:​st14_differential_equation_numerical_models|Modelling:​ Numerical Integration]] 
-  * Chapter 15: [[theory:​sensor_technology:​st15_signal_conditioning_and_sensor_read-out|Signal Conditioning and Sensor Read-out]] 
-  * Chapter 16: [[theory:​sensor_technology:​st16_resistive_sensors|Resistive Sensors]] 
-  * Chapter 17: [[theory:​sensor_technology:​st17_capacitive_sensors|Capacitive Sensors]] 
-  * Chapter 18: Magnetic Sensors 
-  * Chapter 19: [[theory:​sensor_technology:​st19_optical_sensors|Optical Sensors]] <- Next 
-  * Chapter 20: [[theory:​sensor_technology:​st20_actuators|Actuators]] - an example of an electrodynamic motor 
-  * Chapter 21: [[theory:​sensor_technology:​st21_actuator_models|Actuator principles for small speakers]] 
-  * Chapter 22: [[theory:​sensor_technology:​st22_adc_and_dac|ADC and DAC]] 
-  * Chapter 23: [[theory:​sensor_technology:​st23_bus_interfaces|Bus Interfaces]] - SPI, I<​sup>​2</​sup>​C,​ IO-Link, Ethernet based 
-  * Appendix A: [[theory:​sensor_technology:​sta_easyunitconversion|Systematic unit conversion]] 
-  * Appendix B: [[theory:​sensor_technology:​stc_common_mode_rejection_ratio_cmrr|Common Mode Rejection Ratio (CMRR)]] 
-  * Appendix C: [[theory:​sensor_technology:​std_schmitt_trigger|A Schmitt Trigger for sensor level detection]] 
- 
  
theory/sensor_technology/st18_magnetic_sensors.1539104961.txt.gz · Last modified: 2018/10/09 17:09 by glangereis