Current Source Design for 3D Magnetic Field Simulation

2013 ◽  
Vol 760-762 ◽  
pp. 1354-1359
Author(s):  
Zhi Li ◽  
Shu Bao Pan

This paper designs a current source which is used for simulating the three dimensional magnetic field. Gives the circuit schematic, Analyzes the design principle of the circuit and puts forward the calibration method of software which is suitable for the operation in microprocessor and improves the output accuracy of the constant current source. Actual test shows that the output of the constant current source is 0.1mA-500mA and the precision error is less than 0.03% of full scale. It has been used in the degaussing device testing and maintenance. The performance is stable and reliable achieves good results.

1983 ◽  
Vol 55 (2) ◽  
pp. 635-641 ◽  
Author(s):  
C. V. Peterson ◽  
A. B. Otis

When a conductor through which a current is flowing is brought into a magnetic field, the isopotential lines are distorted (E. H. Hall, 1879). When a constant current is made to flow through a Hall generator, the measured voltage perpendicular to the current flow can be made to vary by altering the distance between a permanent magnet and a Hall generator. A length transducer useful for measuring length changes in the diaphragm of a dog is made by connecting a commercially available Hall generator to a Plexiglas plate (5 X 10 X 3 mm, 0.5 g), and suturing the plate to the surface of the muscle. A permanent magnet (20 X 10 X 4 mm, 1.5 g) is attached to the diaphragm at a distance of 2 or 3 cm along the expected direction of length change. Fine wires from the terminals of the Hall generator are connected to an external constant-current source and to solid-state circuitry which provides amplification, linearization, and temperature compensation of the output signal. Model experiments indicate that the length measurements may be accurate within 5% if the distance between the magnet and Hall generator is greater than 5 mm. With this type of transducer measurements of segmental length changes in the diaphragm of an anesthetized dog have been successfully recorded.


2011 ◽  
Vol 82 (1) ◽  
pp. 013906 ◽  
Author(s):  
D. Talukdar ◽  
R. K. Chakraborty ◽  
Suvendu Bose ◽  
K. K. Bardhan

2013 ◽  
Vol 718-720 ◽  
pp. 450-454
Author(s):  
Ning Yang ◽  
Hai Ting Zhu ◽  
Shao Shan Zhong

Thermistor has a large temperature range, good stability and resistance to oxidation, which occupies an important position in the low-temperature measurement. This article describes new two-wire thermistor temperature measurement device using the Freescale MC9S12XS128 MCU with sampling capacitance. The device is composed of the MCU with its own A/D, MC9S12XS128 MCU, sampling capacitance, amplifier, boosted circuit, data acquisition and processing system, constant current source, etc. Using constant current source and 16-bit A/D converter designs the temperature measurement circuit, it can eliminate the effect from the conductor resistances in the traditional two-wire resistance temperature measurement system and reduce the measurement error which conductor resistances bring. The method is simple, practical, with high accuracy, strong anti-interference ability and other characteristics.


2014 ◽  
Vol 945-949 ◽  
pp. 1924-1931
Author(s):  
Hai Qing Yao ◽  
Heng Cao ◽  
Fei Jiang ◽  
Bo Sun

Based on the excellent performance of Pt100, a portable low-cost precision temperature sensor has been designed, whose core chips are REF03, AD8603, AD7788 and precision resistors. Constant current source (CCS) for 4-wire Pt100 is constituted by REF03, AD8603 and precision resistors. AD7788 measures the differential signal on Pt100 and suppresses the common mode interference signal. Analysis software running on the micro control unit (MCU) filters the digital code from AD7788, and then calculates the current temperature value according to the resistance-temperature mathematical model of Pt100. Analysis and experimental results show that the temperature measurement accuracy of the sensor can reach ±1°C within the range of 0°C-650°C.


Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2592 ◽  
Author(s):  
Ming Ma ◽  
Qian Song ◽  
Yang Gu ◽  
Zhimin Zhou

In the field of indoor pedestrian positioning, the improved Quasi-Static magnetic Field (iQSF) method has been proposed to estimate gyroscope biases in magnetically perturbed environments. However, this method is only effective when a person walks along straight-line paths. For other curved or more complex path patterns, the iQSF method would fail to detect the quasi-static magnetic field. To address this issue, a novel approach is developed for quasi-static magnetic field detection in foot-mounted Inertial Navigation System. The proposed method detects the quasi-static magnetic field using the rate of change in differences between the magnetically derived heading and the heading derived from gyroscope. In addition, to eliminate the distortions caused by system platforms and shoes, a magnetometer calibration method is developed and the calibration is transformed from three-dimensional to two-dimensional coordinate according to the motion model of a pedestrian. The experimental results demonstrate that the proposed method can provide superior performance in suppressing the heading errors with the comparison to iQSF method.


2010 ◽  
Vol 22 (4) ◽  
pp. 807-811
Author(s):  
赵娟 Zhao Juan ◽  
曹科峰 Cao Kefeng ◽  
曹宁翔 Cao Ningxiang ◽  
黄斌 Huang Bin ◽  
于治国 Yu Zhiguo ◽  
...  

2012 ◽  
Vol 24 (4) ◽  
pp. 925-928
Author(s):  
赵娟 Zhao Juan ◽  
李波 Li Bo ◽  
于治国 Yu Zhiguo ◽  
曹宁翔 Cao Ningxiang ◽  
黄雷 Huang Lei ◽  
...  

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