极限电流型氧传感器的特性研究

环境气氛条件对氧传感器的性能有直接的影响,本文对极限电流型氧传感器在常压常氧环境和高CO2环境下的输出特性进行了研究,同时根据传感器的前级信号放大电路对使用氧传感器时的取样电阻取值、预热时间进行了研究.     

基于纳米材料气体传感器的接口电路设计

为了在测试的过程中测量纳米材料气体传感器变化的电阻信号,针对高灵敏度的纳米材料气体传感器,设计了一种宽动态范围的快速采样接口电路,基于积分电路的原理,将流经传感器的电流转换成一定脉宽的方波信号,单片机捕获脉冲时间并换算成传感器电阻值。电路在1 kΩ～500 MΩ测量范围内的最大线性误差为5%,能够应用于气体传感器的测试和标定、手持气体检测设备以及电阻测量等领域。     

基于二线制电流型变送的电阻式传感器测试系统的设计与实现

为了实现对电阻式传感器远距离检测的需求,提出了一种基于二线制电流变送的电阻式传感器测试系统设计方案,并完成系统的软硬件设计。该系统的硬件部分主要采用电阻箱模拟电阻式传感器,通过二线制电流变送,经采样电路传入单片机,依据被测的不同电阻值控制后续电路,并将该测试阻值显示于液晶屏上;软件部分通过两个ADC引脚同时128次采样,算平均值求得。实际应用表明,该系统具有操作简便、测试准确、价格低廉的特点,达到了设计要求。     

一种较大驱动电流的锑化铟磁阻式齿轮转速传感器设计

本文介绍一种采用锑化铟-铟共晶体磁敏电阻作为敏感元件的半导体薄膜型齿轮转速传感器，得出了传感器检测距离与磁阻输出信号的关系曲线。传感器驱动级采用推挽输出的形式，输出矩形脉冲负荷能力强，输出拉电流最大可达200mA以上，当温度在-℃30～ 70℃之间变化时，信号处理电路输出依然稳定可靠。     

一种基于忆阻器的大测量范围新型曝光量传感器

为了增大曝光量传感器的测量范围,提出了一种基于忆阻器的新型曝光量传感器设计方案.该传感器主要由光敏电阻、限流电阻和忆阻器组成.光敏电阻的阻值随着光照度的变化而变化,引起回路电流的变化,然后以变化的回路电流激励忆阻器.依据记忆特性,传感器以忆阻器的阻值来表征物体被辐照时光照度在一段时间内的积分值,从而实现对曝光量的测量.实验结果表明,曝光量传感器实现了对曝光量的测量,且具有大的测量范围.光照度为100 lx时,测量范围为0~500 lx·s;光照度以80 lx/s的稳定速率增大时,测量范围为0~1 000 lx·s.另外,限流电阻为0.2 MΩ时的测量上限值比10 kΩ时大780 lx·s,而灵敏度降低了87 Ω/(lx·s).增大限流电阻尽管可以增大传感器的测量范围,但是却降低了灵敏度.     

姿态传感器

本发明敏感机理基于敏感原件内的自然对流气体与热敏电阻的热量交换,环境温度的变化会导致传感器灵敏度的温度漂移。本发明设置角度传感器、传感器电源和中央处理器,传感器电源通过直流电源滤波器与5V稳压器和加热模块相连;稳压器电流一路通过3.3V稳压器输入中央处理器,另一路输入相互垂直的两个角度传感器,信号经滤波后输入中央处理器;中央处理器输出的偏差值通过CAN控制器和CAN隔离收发器模块送到上位机。本发明在姿态传感器电路中设置了加热模块对两个相互垂直的角度传感器进行恒温保护,能有效校正温度变化影响,保证了角度传感器灵敏度,提高了姿态传感器的检测精度。     

用于电阻类传感器校准的电子合成电阻

利用运算放大器和数模转换器等电路构成单口网络,通过编程得到输入电压及电流的比值,获得期望大小的合成电阻。这种合成电阻可以用于对电阻类传感器的测试电路或仪器的自动校准。提出了在提高电阻合成准确度、扩展桥压范围、提高极性适应能力和多通道之间的隔离等方面的解决办法,并对实验结果进行了分析,给出了实用的修正方法。     

液体摆差分电阻倾角传感器设计

为方便、准确地检测大型喷雾机横杆水平状态,设计并制作液体摆差分电阻式倾角传感器。传感器采用液体自水平原理和电阻在液体摆差分变化原理,再利用电桥电路将倾角变化转换为电压变化。设计并制作了水银槽,采用康铜为导电丝制作了倾角传感器装置。在20℃的室温环境下,进行了标定试验和对比试验,获得倾角测定经验公式。试验结果表明:在倾角为-20°～20°的范围内,其测量精度小于±1. 0%,当倾角为-6°～6°时,误差低于0. 02°。     

传感器八片应变计组桥问题探讨

1.前言众所周知,高精确度电阻应变式称重传感器的内部测量电路为惠斯顿电桥。一般至少需要四片工作应变计。这是最基本也是最常用的传感器电路。但目前也有一些传感器采用了八片应变计,如Y型轮幅式传感器和QF型桥式传感器及双悬臂梁式传感器等。用八片应变计的一个主要目的是为了提高这些传感器的抗干扰力的性能。它可通过合理组桥使干扰力的影响很小,从而提高传感器的实际使用价值。目前普遍采用的是应变计串联后组桥。然而已经贴在弹性体上的八片应变计还可以组成其它形式的电路,以实现不同的目的。本文将专门对八片应变计的组桥形式进     

InSb-In共晶体薄膜磁阻式电流传感器

介绍一种用锑化铟—铟 (InSb -In)共晶体薄膜磁阻元件 (MR)制成的电流传感器 (MRCS) ,并设计了一种能较大幅度增大其输出电压的信号处理电路。当处理电路的电压增益为 80db ,待测的 5 0Hz交流电流在 40～ 110mA之间变化时 ,输出电压在约 1V至约 3 .5V范围内变化 ,并且两者之间有比较好的线性关系 ,标准偏差 <0 .0 2。输出信号电压与本底噪声之比是 (2 4～ 46 ) :1。     

Calibration of MEMS strain sensors fabricated on silicon: theory and experiments

A calibration technique for measuring MEM's strain sensor performance is presented. For resistance based sensors, calibration entails determining a relationship between change in resistance of the sensor and strain (the gauge factor). A modification to the standard calibration method employed for metal foil, resistance strain gauges is presented. The approach entails constructing two nearly identical test specimens: a specimen with the MEM's sensor mounted with adhesive and a specimen with a strain gauge on silicon mounted with adhesive. Data from the strain gauge specimen provide the basis for evaluating the strain at the sensor. Test data are presented which show that strain at the wafer is 52% to 55% of the strain applied to the specimen. A theoretical basis for this strain transfer relationship is presented. Finally, a dimensionless geometry factor, based on shear lag theory, is derived. As the sensor cross section (width and length) and thickness changes, the strain transfer between the specimen and sensor vary linearly with the geometry factor. This result emphasizes the importance in considering the overall sensor geometry when employing semiconductor strain gauges.     

基于传感器的自动调焦系统设计

分析了大气压力、温度和摄影斜距的变化对航空相机离焦的影响,给出了计算相机离焦量的简易数学方程,介绍了基于高精度硅压力传感器、铂热电阻温度传感器和GPS的数据采集处理的自动调焦系统组成和设计原理,制作完成了系统的硬件电路和软件流程设计,经过光学测试和实际应用证明:这种设计实用可靠,调焦速度快,精度高,完全满足高机动性航空...     

Effect of trace residual ionic impurities on the response of chemiresistor sensors with dithiol-linked monolayer-protected gold (nano)clusters as sensing interfaces

Column liquid–solid chromatography was used to remove residual impurities of isolated n-octanethiol (C₈H₁₇SH) monolayer-protected gold nano-clusters (MPCs) which were synthesized by a Brust two-phase method. Three-dimensional (3D) cross-linked MPC films were prepared directly on interdigitated electrodes to form chemiresistor sensors through the exchange reactions of the chromatographically purified MPCs with 1,6-hexanedithiol (HDT) or 1,4-benzenedimethanethiol (BDT). Ionic current induced by trace residual ionic impurities in MPCs was qualitatively detected by comparing the resistance responses of the sensors interfaced with the chromatographically purified and unpurified MPC films by employing volatile organic compounds (VOCs) and water vapor as probes, respectively. The existence of the ionic current significantly decreases the sensor sensitivities to VOCs. As for water vapor with high permittivity, the ionic current totally distorted the resistance responses from positive to negative with increasing humidity. Capacitance was also measured to characterize the permittivity change. The effect of ionic current on capacitance was not obvious. The humidity effects on the sensor responses to VOCs were also investigated. Fewer effects were observed on the higher hydrophobic compounds. A ternary sensor array was constructed with C₈Au MPCs, HDT and BDT cross-linked MPC films as sensing interfaces. The response pattern showed that the sensor array could discriminate VOCs with different functional groups. The as-prepared sensor showed the same sensitivities as the acoustic wave sensors.     

Multi frequency interrogation of polypyrrole based gas sensors for organic vapors

Polypyrrole exhibits reversible changes in their direct current resistance on exposure to organic volatiles. However, one needs to employ an array of such sensors to discriminate organic volatiles present in a mixture. Hence, polypyrrole based gas sensor is designed for the detection and discrimination of different organic volatiles. Multi frequency impedance measurement technique is used to detect the organic vapors, such as acetone, ethanol and Isopropyl alcohol, in the gas phase, over a frequency range 10 Hz to 2 MHz. The sensor response is monitored by measuring the changes in its capacitance, resistance and the dissipation factor upon exposure to organic volatiles. It is observed that the capacitive property of the sensor is more sensitive to these volatiles than its resistive property. Each volatile responds to the sensor in terms of dissipation factor at specific frequency and found that the peak magnitude has a linear relationship with their concentrations.     

巨磁阻抗磁传感器研究进展

巨磁阻抗效应是指材料的交流阻抗在外加直流磁场的作用下发生显著变化的现象,利用该效应研制的巨磁阻抗磁传感器具有灵敏度高、体积小和功耗低等特点,具有巨大的应用前景.分析了巨磁阻抗磁传感器的研究现状,重点介绍了磁场传感器、电流传感器和生物传感器的工作原理和特性,并指出了其目前存在的问题和发展趋势.     

Development of wireless compressive/relaxation-stress measurement system integrated with pressure-sensitive carbon black-filled silicone rubber-based sensors

In order to detect the installation compressive stress and monitor the stress relaxation between two bending surfaces on a defensive furnishment, a wireless compressive-stress/relaxation-stress measurement system based on pressure-sensitive sensors is developed. The flexible pressure-sensitive stress sensor array is fabricated by using carbon black-filled silicone rubber-based composite. The wireless stress measurement system integrated with this sensor array is tested with compressive stress in the range from 0 MPa to 3 MPa for performance evaluation. Experimental results indicate that the fractional change in electrical resistance of the pressure-sensitive stress sensor changes linearly and reversibly with the compressive stress, and its fractional change goes up to 355% under uniaxial compression; the change rate of the electrical resistance can track the relaxation stress and give out a credible measurement in the process of stress relaxation. The relationship between input (compressive stress) and output (the fractional change in electrical resistance) of the pressure-sensitive sensor is ΔR/R₀ = σ × 1.2 MPa^?1. The wireless compressive stress measurement system can be used to achieve sensitivity of 1.33 V/MPa to the stress at stress resolution of 920.3 Pa. The newly developed wireless stress measurement system integrated with pressure-sensitive carbon black-filled silicone rubber-based sensors has advantages such as high sensitivity to stress, high stress resolution, simple circuit and low energy consumption.     

MEMS传感器的标准化现状与发展对策

随着MEMS传感器在各个领域的广泛应用,传感器领域的标准化工作思路和技术路线发生了变化。论述了目前国内外MEMS传感器标准的现状,并就国内外MEMS传感器标准体系的发展过程、特点、标准体系存在的问题、与现有半导体标准的关系进行了分析探讨,同时,对我国MEMS传感器标准的发展对策提出了建议。     

电涡流传感器在混合悬浮控制器中的应用

位移信号传感器作为磁悬浮系统的一个信号采样装置,用来检测悬浮磁铁的位移信号,并将该信号传送给控制器,作为控制器进行控制和调节的参考信号,位移传感器工作性能的好坏将决定着整个控制系统能否正常工作。介绍了电涡流传感器的工作原理、结构及其在混合悬浮控制器中的应用。实验结果表明：电涡流传感器应用于混合悬浮控制器中,灵敏度高,结构简单,抗干扰能力强,为进一步提高混合悬浮控制系统的精度给出了新的途径。     

实用的在线光纤电流传感器

提出了一种由磁致伸缩材料管和光纤光栅构成的新型光纤光栅电流传感器。实验结果表明该传感器有良好的线性响应 ,并且不受磁滞效应的影响。波长漂移对线电流的灵敏度为 0 .0 0 0 74nm/A     

柔性高灵敏单壁碳纳米管气体传感器研究

在柔性聚对二甲苯C基底上制作了基于单壁碳纳米管的小型化、高灵敏、反应快速的气体传感器。使用介质电泳集成碳管束,并利用单链脱氧核糖核酸修饰增强器件灵敏度。当传感器暴露在甲醇蒸气中时,会出现明显可重复的反应,它可以检测含量低至4.3×10-6的甲醇,并且在相当宽的体积分数范围有清晰的分辨能力。对于4.3×10-6的含量,未修饰的传感器对应电阻变化率是4.8%;经过脱氧核糖核酸修饰,电阻变化率增加到了12.3%。此外,该传感器还显示了很快的响应速度和很好的测试复验性。研究表明:这种柔性气体传感器在未来环境监测应用中有很好的前景。