共查询到19条相似文献,搜索用时 109 毫秒
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热敏电阻器是一种对温度变化很敏感的电阻器。在工作温度范围内,其阻值随温度的升高而减少的热敏电阻器称为负温度系数热敏电阻器(即NTC热敏电阻器)。在工作温度范围内,其阻值随温度升高而增大的热敏电阻器称为正温度系数热敏电阻器(即PTC热敏电阻器)。附图为几种不同类型的热敏电阻器的阻温特性曲线。热敏电阻器的标称阻值R25是指在环境温度为25℃时,采用规定的外加测 相似文献
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目前,敏感电阻的种类较多,比较常见的有热敏电阻、光敏电阻,压敏电阻、力敏电阻、磁敏电阻,湿敏电阻和气敏电阻,下面就分别简要介绍。一、热敏电阻。热敏电阻是一种电阻值对温度非常敏感的电阻器,这种电阻一般由单晶、多晶等半导体材料制成,其种类较多,如根据阻值的温度系数、可分为阻值随温度升高而减少的负温度系数热敏电阻和阻值随温度升高而增加的正温度系数热敏电阻;如按阻值随温度变化的大小及变化速废;可分 相似文献
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介绍一种类R-F转换频率测量温度的方法,由AVR单片机引脚输出的高低电平通过热敏电阻和标准电阻对电容充放电,并由外部输入捕获中断测量充电时间,然后单片机根据测得的时间和标准电阻阻值计算出热敏电阻的阻值,查表得到温度值.详细介绍了该方法的测量原理,给出了主要程序流程图和关键程序代码,并在一款温度计的设计中成功运用了该方法,实现低成本、高精度的温度测量. 相似文献
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Matthew Beckner 《电子设计技术》1996,(4)
虽然热敏电阻器的响应通常是非线性的,但可以在温度线性度的一个可选范围内实现装置的阻值。可以将热敏电阻器的阻值转换成电压,显示在DMM(数字万用表)或面板仪表上。图1中的电路实现了线性化,并为YS144031热敏电阻器提供增益和偏置,此热敏电阻器标称阻值在25 相似文献
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玻璃管型及玻璃珠型热敏电阻,属NTC负温度系数热敏电阻器。其阻值随温度升高而变小,是目前用得较多的温敏元件之一。这种热敏电阻,具有灵敏度高、体积小、时间常数小、寿命长、稳定性好以及价格便宜等优点。玻璃管型及玻璃珠型高灵敏度NTC热敏电阻器的外形如图1所示。各种NTC热敏电阻的尺寸和对应的标称阻值 相似文献
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设计了一种基于PIC16C71单片机的数字水温配制阀。该配制阀采用NTC热敏电阻作温度传感器,与固定电阻组成简单分压电路作为水温测量电路,利用PIC16C71单片机内置的8位A/D转换器把热敏电阻上的模拟电压转换为数字量,PIC16C71单片机控制直流电机驱动混水阀调节冷热水的混合比例实现水温调节。给出了控制电路图,对水温测量电路的参数选择和测温精度作了详细讨论。实验和分析表明,选用阻值较大的NTC热敏电阻和分压电阻可较好地解决热敏电阻因功耗较大造成的热击穿问题。 相似文献
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提出了一种基于555定时器和单片机的温度测量电路设计方案。利用负温度系数热敏电阻测量外界温度,通过555定时器构成的多谐振荡器将温度传感器的阻值转换成频率信号,利用单片机的定时器测量振荡电路的振荡周期,由查表法得到实际温度值,从而实现温度测量。温度测量范围为0℃-99℃,分辨率为±1℃,体积小,成本低,工作可靠,可广泛应用于日常生活中。 相似文献
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Multisim仿真软件中没有热敏电阻模型,通过应用Multisim 11.0元件库中的基本电阻元件结合热敏电阻的温度特性,介绍了设置PTC、NTC的仿真近似模型的方法,将该热敏电阻模型应用于小冰箱的制冷控制电路中,对其温控系统进行了相应的参数扫描仿真分析,实现了预期的温控功能,从而验证了该模型建立的正确性。 相似文献
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O. Mrooz A. Kovalski J. Pogorzelska O. Shpotyuk M. Vakiv B. Butkiewicz J. Maciak 《Microelectronics Reliability》2001,41(5)
Degradation processes, caused by the extreme values of current pulses or thermal burn-in, are studied in thermistors with negative temperature coefficient of resistance. The drift of thermistor resistance at 25°C is observed. These changes depend on the value and the number of current pulses. The first 100 cycles are the basic ones for the future exploitation parameters of thermistors. Similar effect, rise of thermistor resistance, was observed after burn-in. The investigated thermistors are used for in-rush current protection of electronic circuits. 相似文献
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A general and simple chemical approach has been proposed to prepare negative temperature coefficient (NTC) powder material using commercially available tetra hydrated acetates of Mn, Co, Ni and oxalic acid. The thermal decomposition of Mn-Co-Ni oxalate at 700 °C leads to formation of spinel phases with fine powder material. Lead free thick film thermistor pastes were formulated using the synthesized spinel powders. Planar thick film thermistor patterns of the formulated pastes were screen printed on alumina substrates. The microstructure and electrical properties of these thick film thermistors were determined. Depending on the powder preparation, the prepared thick film NTC thermistors showed room temperature resistance in the range of 12-29 MΩ. The values of thermistor constant, β25/300 ranged from 4014 to 4223 K. 相似文献
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Zhixiang Cai 《Microelectronic Engineering》2009,86(1):10-15
In this paper, laser sintering has been used to process thermal sensitive material deposited by micro-pen direct-write technology. Lines of thick-film PTC thermistor paste were deposited by micro-pen direct-write technology and irradiated by a continuous-wave laser with varied power density and scanning speed. Line widths, sheet resistivities and temperature coefficients of resistivity were measured as a function of laser power density, scanning speed, coating thickness and overlapped value. The mechanism of laser sintering thermistor paste was discussed. Laser sintering enabled finer thermistor lines to overcome the resolution limitation of micro-pen deposition without the use of any high temperature post processing. The thermistors exhibited excellent electrical performance and resistance tolerance equivalent to traditional oven-fired electronic paste. 相似文献