共查询到19条相似文献,搜索用时 421 毫秒
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为了避免化学标准电池由于自身特点在使用中存在诸多不便,采用集成温度传感器LM334设计制作了电子标准电池,同时在设计电路中还采用了两级稳压措施以保证标准电池输出的稳定性. 相似文献
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本文介绍了定流变阻式电位差计灵敏度和标准电池内阻的测量原理和方法,给出了测量实例,并以内阻为指标讨论了标准电池的报废标准 相似文献
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板式电势差计原理如图1所示.先将开关SG打向1,使用标准电池Es把电势差计的工作电流标准化后再将SG打向2,即可对0、2间所接的待测电池电动势Ex进行测量。 相似文献
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标准电池的内阻,不但是研究标准电池的一个指标,也是校准低阻电位计时选择电流计的依据。标准电池内阻约有数百欧姆。对于Ⅰ,Ⅱ类标准电池,允许连续通过的电流不超过1微安。如果直接把电池连接一电阻R′测出电动势和端电压之差,则因为了使电流不超过限值,必须有R>10~6欧。同时电池内阻r(?)10~2欧。这 相似文献
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科研、生产及实验室使用标准电池,要求有稳定的正确的电动势和正常的内阻。可是在工作中发现有些标准电池,经长期使用或管理不当往往内阻增高,甚至有的呈现内阻趋向无穷大的开路情况,这样会失去电压标准的要求。一般标准电池出现故障不易修复,对上述故障,则有修复的可能。 相似文献
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将2只型号相同的标准电池进行反接,借助直流复射式灵敏电流计为指示器测量标准电池内阻,并对回路灵敏度不足产生的误差进行了分析,总结出提高测量精度的几点措施. 相似文献
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标准电池的内阻,不但是研究标准电池的一个指标,也是校准低阻电位计时选择电流计的依据。标准电池内阻约有数百欧姆。对于Ⅰ,Ⅱ类标准电池,允许连续通过的电流不超过1微安。如果直接把电池连接一电阻R′测出电动势和端电压之差,则因为了使电流不超过限值,必须有R>10~6欧。同时电池内阻r≈10~2欧。这样,电动势和端电压之差额仅约为电动势的万分之几,故内阻测量只能有1—2位有效数字,而且相应地要求辅助电路的元件具有相当高的稳定值。 相似文献
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A K Gupta N S Natarajan V S Tomar N D Kataria V K Batra A V Narlikar K Chandra 《Pramana》1987,28(5):517-527
A C Josephson effect is now used by several countries as the reference standard for the unit of d.c. voltage. This paper describes the work done at the National Physical Laboratory (NPL), New Delhi in the realization of the unit of volt based on the a.c Josephson effect. A voltage standard at 1 mV level using a Nb-Nb point contact junction has been established and the as-maintained volt based on a bank of standard cells has been intercompared against it using a 1:1000 voltage divider. The experimental set-up used in this comparison and the results of recent measurements are described. The overall uncertainty in assigning the value of emf to a standard cell is about 1 ppm. The as-maintained volt has been found to agree with the Josephson voltage within overall uncertainty. 相似文献
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J. A. Dharmadhikari A. K. Dharmadhikari N. Y. Mehendale R. C. Aiyer 《Optics & Laser Technology》1998,30(6-7)
The paper describes a low cost Pockels cell driver for Q-switching flash lamp pumped pulsed solid state lasers. The driver consists of a high voltage pulsed power supply variable from 0 to 5 kV using a standard step up transformer. The pulse width and pulse repetition rate are varied using standard TTL circuits from 50 μs to 2 ms and 1 ppm to 50 Hz, respectively. The pulsed high voltage along with a high voltage switch consisting of a stack of bipolar transistors is used to drive a Pockels cell. The Q-switched pulsed duration measured in Ruby and Nd-YAG lasers are 35 and 15 ns, respectively. The Pockels cell driver performance is consistent for more than 5×107 shots. 相似文献
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The electrostatic AC-DC voltage comparator for precise voltage measurement in voltage range of 100–1000 V and frequency range of 20–100,000 Hz was designed. The equality of AC and DC voltages transforms into horizontal positioning of the beam, which is registered by two photoelectric transducers. DC voltage was measured by voltage divider, standard cell and low-voltage comparator. The construction, main characteristics, and sources of errors are described. The comparison error has been determined as having the value of 0.003% at the voltage of 100 V and the value of 0.0009% at the voltage of 1000 V. 相似文献
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按照新课程标准的要求,针对高中物理粤版选修教材中存在的不足,在制作原电池方面做了相应的改进.用重铬酸钾做电解质溶液中的氧化剂,用蓬松棉做盐桥,并用碳棒做电池正极.同时将该方法制做的原电池引入探究原电池内电压和外电压的关系和电池内电阻的大小2个实验中. 相似文献
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Macroscopic cell experiments and three-dimensionalmodelling on electrode-shaping plasma display cell
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A macroscopic cell and three-dimensional fluid model have been used
to investigate the discharge characteristics in ac plasma display
panel cells of electrode-shaping configurations. Four kinds of
non-standard geometries (i.e. $D$-, ${\it\del}$-, $W$- and $U$-shape
electrodes) have been considered. The characteristics of the
discharge current, the operating voltage and the discharge
efficiency of different configurations have been discussed. It is
found that the discharge efficiency can be improved by about
10\%--30\% compared with the standard geometry, while the operating
voltage increases slightly in the non-standard geometries. There is
a trade-off between improving the discharge efficiency and lowering
the sustaining voltage in design of plasma display cells by
electrode shaping. 相似文献
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Ahuja R Blomqvist A Larsson P Pyykkö P Zaleski-Ejgierd P 《Physical review letters》2011,106(1):018301
The energies of the solid reactants in the lead-acid battery are calculated ab?initio using two different basis sets at nonrelativistic, scalar-relativistic, and fully relativistic levels, and using several exchange-correlation potentials. The average calculated standard voltage is 2.13?V, compared with the experimental value of 2.11?V. All calculations agree in that 1.7-1.8?V of this standard voltage arise from relativistic effects, mainly from PbO2 but also from PbSO4. 相似文献
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高场不对称波形离子迁移谱非线性函数系数误差分析 总被引:1,自引:0,他引:1
离子迁移率非线性函数系数α2和α4是高场不对称波形离子迁移谱(FAIMS)实现物质识别的基础。现有的α2和α4缺少先验值和误差分析方法,因此有必要建立关于α2和α4求解结果误差的评估标准,进而在此基础上提高α2和α4的求解精度。通过自制FAIMS分别对丙酮、异丙醇和1,2二氯苯三种物质在不同分离电压下的检测实验,获取样本在不同分离电压下的谱图和谱图特征值,运用组合的方法从多组分离电压值和相应补偿电压值的数据中选取指定组数,计算出大量的α2和α4数据。通过对α2和α4的数值分析,探究了α2和α4的分布特点和二者之间的相关性,研究了分离电压取点数量和取点方式对其求解结果误差的影响。在拟合α2和α4数据不同范围的频数后,发现α2和α4符合正态分布,其拟合度均在0.96以上,可以利用α2和α4分布的标准差来评估其求解结果的误差。通过对(α2, α4)散点进行拟合,发现α2和α4之间具有很强的负相关性,三样本的相关度分别为-0.977,-0.968,-0.992。随着分离电压选取点数的增加,其相应的求解结果误差在不断减少。通过不同分离电压取点方式的对比,发现当分离电压取VDmax和0.7 VDmax时求解结果最优。在保证α2和α4求解的准确性的前提下有效降低了检测次数,为FAIMS实现快速现场检测和精确的谱图解析创造了有利的条件。 相似文献