- 标题
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Noise-optimized ultrastable low-noise current amplifier
摘要： We have developed a noise-optimized ultrastable low-noise current amplifier (ULCA) aimed at reducing the uncertainty at low currents. It involves a thin-film resistor network with 6.75 GΩ at the high-ohmic path which reduces the noise level to 1.6 fA/√Hz. Noise investigations as well as short-term and long-term stability studies were carried out. The stability of the input current gain was measured using a cryogenic current comparator at ±6.1 nA. Methods for investigating the measurement accuracy at low input currents of about 100 pA at a level of below one part in 10^7 are introduced and experimentally verified. The performance of the noise-optimized ULCA is compared with that of the standard variant introduced in 2014. It is shown that the reduced noise floor is achieved without impairing the stability of the transresistance.
关键词： low-current measurement,cryogenic current comparator,current amplifier,stability,noise optimization
更新于2025-09-23 15:22:29
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Quantum States of Heralded Photons
摘要： In this paper, the design and the development of a remote system for continuous monitoring of leakage currents and ground currents in high voltage electrical substations are proposed. Based on wireless local area network technology, the system can be used to monitor continuously a variety of plants within the substation and has low power consumption with inbuilt overvoltage protection. It consists of a transmitter module equipped with a data acquisition (DAQ) system connected to leakage current and voltage sensors, and a receiver module connected to a remote controller for data processing and storage. The principle of operation and the characteristics of the various components of the system are described. Validation tests have been used to verify its performance in three different test situations: A) laboratory monitoring of the leakage current and voltage of a distribution surge arrester; B) laboratory measurement of the leakage current of an outdoor insulator; and C) ?eld monitoring of the earth current and potential rise of high-voltage tower. The measured results are in close agreement with those recorded directly through a DAQ card with ?ber-optic and coaxial cable connected systems. Data processing is carried out at the receiving end so that the monitored parameter is displayed continuously or at speci?ed time intervals. The operation of the system has been tested and proved resilient under high-frequency interference signals such as those generated by corona and surface discharges.
关键词： wireless transmission,solar power,surge arrester,data acquisition,high-voltage substation,leakage current measurement,insulator,WLAN system,Continuous monitoring
更新于2025-09-23 15:21:01
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[IEEE 2019 International Seminar on Research of Information Technology and Intelligent Systems (ISRITI) - Yogyakarta, Indonesia (2019.12.5-2019.12.6)] 2019 International Seminar on Research of Information Technology and Intelligent Systems (ISRITI) - Parameter Tuning of G-mapping SLAM (Simultaneous Localization and Mapping) on Mobile Robot with Laser-Range Finder 360?° Sensor
摘要： The application of a binary step-up method has been investigated at the Korea Research Institute of Standards and Science (KRISS) for establishment of high dc standards based on the calibration system of high dc shunts up to a few thousand amperes in which the current dependence of the shunt resistance can be measured. A successive step-up method with a pair of high dc shunts was suggested to link the unknown high current to the values of low current level which are already known. The step-up approach was further modified with employing a current monitor to extract the information on the current dependence of the shunt and the source current changes during the step-up measurement. To validate the modified step-up technology, a comparison of high dc shunt resistance was carried out with National Research Council (NRC) in which both the KRISS and the NRC results agreed well within the standard deviation of the measurement on the order of about 0.01%.
关键词： current measurement,Calibration,current supplies,current transformers,shunts,electrical resistance measurement
更新于2025-09-19 17:13:59
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Current Comparator Based Current Divider
摘要： The paper describes a current divider (or splitter), i.e., a device that allows the splitting of an alternating current (ac) in two parts in a precise and accurate current ratio. It is based on current comparator techniques so that precise current ratios can be attained with ratio errors bearing parts in 106 to 109. A binary current divider can be made virtually exact (i.e., with unitary current ratio errors of the order of some 10-9 only), if aided by electronic flux error compensation. Further, coupled transmission lines modeling can assess its current ratio errors over frequency. A current divider finds application in many areas of ac metrology as in highly accurate impedance bridges and current measurements.
关键词： Circuit and systems,current measurement,measurement uncertainty,measurement techniques,impedance measurement,current mode circuits
更新于2025-09-10 09:29:36
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - A Simultaneously Comparison of Three Current Transformer Calibration Systems
摘要： This paper shows a novel method for simultaneous comparison of three current transformer calibration systems at power frequency. All three systems are designed for the calibration of high accuracy current transformers. The measuring method is also suitable for inter-laboratory comparisons of calibration systems/methods. The paper gives a description of the novel measuring method and the compared measuring systems. The comparison results are shown and discussed.
关键词： calibration,current comparator,AC current measurement,uncertainty of measurement,current transformer
更新于2025-09-10 09:29:36
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Development of a Shunt for High Intensity DC and AC Currents with NMR Measurement of the Magnetic Field
摘要： This paper describes the development of a new design of a DC and AC shunt to high intensity current. The working principle is based on the measurement of the magnetic field using a nuclear magnetic ressonance or a NMR method. The traceability comes only from frequency and a geometric parameter. The preliminary results of a prototype are presented. Also, it is described a new non-inductive method to measure the magnetic AC component. The final device - a shunt to be used as a primary standard - is intended to operate in kA range.
关键词： Current measurement,high intensity current,NMR shunt,AC shunt,NMR measurement,current standards
更新于2025-09-10 09:29:36
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Calibration of AC Shunts at Frequencies Up to 10 kHz Using Digital Sampling
摘要： This paper describes a calibration system for AC shunts using digital sampling. It provides both ratio errors and phase displacements of a shunt under test with respect to a reference shunt. In its basic configuration, the calibration system operates at currents of up to 10 A and frequencies of up to 10 kHz. The expanded uncertainties (k = 2) of the described calibration system are estimated to be better than 30 μA/A for magnitude and 30 μrad for phase at 10 kHz, and lower than these at lower frequencies.
关键词： calibration,calculable resistor,current comparator,current measurement,measurement uncertainty,AC shunt,measurement standards
更新于2025-09-10 09:29:36
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Low-Noise Measurement Setup for Single-Electron Pumps
摘要： Single-electron pumps (SEPs) applied as quantum current sources are a fundamental part of a future quantum triangle experiment. To characterize an SEP in a reasonably short time, a low-noise setup is needed. We present an improved measurement setup tailored for current measurements on SEP, characterized by a low-noise wiring and a new variant of the ultrastable low-noise current amplier (ULCA). The evaluation shows that the setup is suitable for measuring a 100 pA current with a relative uncertainty of 0.1 μA/A within about 14 hours.
关键词： Current measurement,measurement uncertainty,noise measurement,measurement standards,low-noise amplifiers
更新于2025-09-10 09:29:36
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Current Divider Based Impedance Comparator
摘要： The paper describes an ac impedance measurement comparator system which uses a current divider (or splitter). The divider makes use of a current comparator whose windings are connected in a way such as to allow the splitting of a single current signal in two components with very accurate ratio to be attained. Each current component flows through impedances to be compared. Preliminary investigations indicate that such an arrangement is able to provide very accurate impedance measurements with errors of parts in 106 or even smaller. Resolutions of parts in 109 were also experimentally achieved. Since the system uses a single ac current source, inherent current instabilities of the source cause negligible effects on differential voltage measurements, what alleviates requirements on the ac source. Digital sampling can easily be implemented with the system for speeded-up and automated impedance comparisons.
关键词： Circuit and systems,current measurement,Hall effect devices,measurement uncertainty,measurement techniques,impedance measurement,electronic circuits,electrical resistance
更新于2025-09-10 09:29:36
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Design and Modelling of a Shunt for Current Measurements at 10 a and up to 1 MHz: A Theoretical Approach
摘要： Electrical current shunts used as resistance standards in metrology laboratories are characterized by a broadband operating frequency bandwidth and are commonly calibrated up to 100 kHz. The use of a current shunt requires the preliminary knowledge of its magnitude deviation from DC and phase angle according to the frequency. The best magnitude performances published so far are limited to 2 μΩ/Ω at 100 kHz. In this paper, we present an innovative shunt design for current measurements at 10 A up to 1 MHz. The relative deviation from DC is less than 0.2 μΩ/Ω and 20 μΩ/Ω in magnitude at 100 kHz and 1 MHz respectively.
关键词： calibration,AC–DC transfer,Current shunts,3D thermal simulation,current measurement,3D electromagnetic simulation,uncertainty,AC current,modeling
更新于2025-09-10 09:29:36