Electrical Test Method Research Articles

Electrical non-invasive determination of aging progress and failure mechanisms of field aged automotive lead batteries

The increasing prevalence of electrically assisted functions in vehicles makes a reliable and safe power supply from the 12V lead battery more important to meet high safety requirements. In addition to traditional battery demands – Starting, Lighting, Ignition – new performance requirements related to a ‘safe stop maneuver’ have emerged. To ensure a consistent safety approach for the vehicle and its electrical system, it is crucial to understand the reliability of the battery, including its aging and failure behavior. Previous methods for determining reliability and failure rates based on subjective teardown analyses can result in different assessments, highlighting the need for an objective method for failure determination. This study presents a nondestructive electrical test method for 12V lead batteries from car workshops and roadside assistance that identifies aging progress and dominant aging mechanisms through equation-based analysis of measured data. The battery’s ability to maintain a specified voltage threshold during an alternative load profile, the ‘safe stop maneuver’ is used to evaluate its performance for future driving applications. Teardown analyses confirmed the aging mechanisms identified during electrical testing. With a sufficiently long observation period to account for seasonal effects, this test procedure can be used to establish an objectively determined sample for further statistical reliability analyses. The results of the procedure will be published in a follow-up study.

Open Defect Detection Not Utilizing Boundary Scan Flip-Flops in Assembled Circuit Boards

An electrical interconnect test method is proposed to detect and locate open defects occurring at interconnects between integrated circuits (ICs) and a printed circuit board. The test method does not utilize boundary scan flip-flops. It is based on a quiescent supply current that is made to flow through an interconnect under test by embedding a test circuit into the ICs. The circuit consists of MOS switches for each input pin of the ICs and its switch control circuit. SPICE simulations are used to examine whether open defects at the interconnects can be detected using this method. The simulation results indicate that the following defective interconnects are detected in addition to defective ones modeled as an open-circuit fault at a test speed of 25 MHz: defective interconnects modeled as a resistor of 150 $\Omega $ generating an additional propagation delay of 482 ps and as a capacitor of 4 pF generating an additional propagation delay of 128 ps and no logical changes. Testability of open defects using this test method is also examined experimentally by prototyping an IC in which the test circuit is embedded. The experiments indicate that a resistive interconnect of $150~\Omega $ and a defective one modeled as a capacitor of 2.2 nF can be detected by the test method at a test speed of 0.5 MHz.

Method of selecting step stress test parameters for XLPE insulation DC voltage endurance coefficient

Cross-linked polyethylene (XLPE) insulation DC voltage endurance coefficient (VEC) is an important basis in the selection of DC cable insulation design and factory test parameters. Studies on the degradation of XLPE insulation performance under DC electric field can also provide technical support for the reliability evaluation of cable operation. The step stress method as an efficient electrical life test method is widely used to obtain VEC. The parameters of step stress method present considerable influences on VEC. An analytical method based on the trajectory of the damage curve and equivalence between step stress test and constant stress test within zone division is proposed in this paper. According to the proposed method, several sets of step stress tests with different test parameters have been carried out. The accuracy of the test results has been confirmed via analyzing test data. The experimental results show that the VEC (n=12.0) obtained by the step stress test whose parameters are selected by proposed method has good equivalence with the result (n=12.2) under constant-stress method.

Electrical Probing Test for Characterizing Wideband Optical Transceiving Devices with Self-Reference and On-Chip Capability

An electrical probing test method is proposed based on serial or parallel modulation mixing scheme for characterizing wideband optical transceiving devices including high-speed semiconductor laser diodes, electro-absorption modulators, photodetectors, and Mach-Zehnder modulators. The method enables self-referenced frequency responses measurement, such as modulation index of semiconductor laser diodes, modulation index of electro-absorption modulators, responsivity of photodetectors, and modulation index and half-wave voltage of dual-parallel Mach-Zehnder modulators, dual-drive Mach-Zehnder modulators, and push-pull Mach-Zehnder modulators. In the demonstration, the experimental results are compared to those obtained with the conventional optical or electrical methods for accuracy. The full-electrical test nature is promising for microwave characterization of wafer level devices and circuits with fully integrated transceiving components on chip.

Minority Carrier Injection in High-Barrier Si-Schottky Diodes

In this paper, we investigate the presence of minority carriers and their role in charge carrier transport in silicon (Si) Schottky diodes with a high potential barrier. Using TCAD simulations along with an analytical model, we show that an inversion charge is induced at the metal–semiconductor (MS) interface in a high-barrier Schottky diode which imparts bipolar-type current characteristics to otherwise a unipolar Schottky diode, even at low-injection operation. In such a high-barrier diode, minority diffusion also becomes important along with the majority carrier thermionic emission and therefore cannot be neglected, unlike in a conventional Schottky diode. The presence of minority carriers at low injection in a high-barrier Si Schottky diode has been experimentally verified via a prior-reported two-diode electrical test method, reverse recovery measurements, and by measuring infrared electroluminescence. It is also shown, via TCAD simulations, that the diffusion component becomes more pronounced in case of a reduced Gummel number and at elevated temperatures.

Electrical conductivity for seed vigor test in sorghum (Sorghum bicolor)

Fatonah K, Suliansyah I, Rozen N. 2017. Electrical conductivity for seed vigor test in sorghum (Sorghum bicolor). Cell Biol Dev 1: 6-12. The objectives of this study were to obtain electrical conductivity test method for seed vigor test in sorghum, to recognize relationship between electrical conductivity test and potassium leakage, and to recognize relationship between electrical conductivity test and other variable on seed vigor. This study have two step experiments. The objective of Experiment I was to determine accurate combinations of water volume and amount seed of the electrical conductivity test for seed vigor test in sorghum. Completely Randomized Design of 15 seed lots with 3 replications were used to determine electrical conductivity method with different vigor. Experiment II were to test electrical conductivity method of 21 seed lots of sorghum without accelerated aging test and 21 seed lots of sorghum were given accelerated aging test. Completely Randomized Design of 21 seed lots with 3 replications were used in Experiment II. The variable were observed : standard germination, field emergence, speed of germination, first count, conductivity, potassium leakage and eight combination conductivity method of water volume (50, 100, 150 and 200 ml) and amount of seed sorghum (50 and 75 seed count). The result of this experiments showed that electrical conductivity test method with 150 ml water volume and 75 seed count was accurate and suitable for sorghum seed vigor test; electrical conductivity test showed positive correlation with potassium leakage;and electrical conductivity test can be used for seed vigor test in sorghum and provided the potential of physiological seed were shown through : standard germination test, field emergence test, first count test and speed of germination with negative correlation.

An electrical test method for quality detecting of wafer level eutectic bonding

As the costs of packaging and testing account for a substantial portion of microelectromechanical system (MEMS) devices, an effective and convenient characterization method is urgent to be investigated to lower the cost. In this paper, an electrical test method was utilized, and the test key used for a four-probe current-voltage test was designed to monitor the quality of the AuSn eutectic bonding. The electrical test can directly detect whether or not voids existed in the bonding layer. The difference in alloy state, for example, the existence of the (Au, Ni) 3Sn2 phase confirmed by the scanning electron microscope and energy dispersive x-ray spectroscopy test, can also be reflected by resistivity variation. The electrical test can be implemented automatically and conveniently unlike other characterization methods. Therefore, it is suitable to be applied in quality inspection in industrial production.

A quick electrical inspection method of solder joint quality for LED products

Solder joint qualities of light-emitting diodes (LED) lamps have a significant effect on their lifetime. Due to variations in LEDs, the product lifetime is determined by the lowest performing component of the product when multi-LEDs are used. In this paper, we propose a quick electrical inspection method of solder joint quality for LED products, which is obtained by the heating curve measurement for a short time with the forward voltage as a temperature sensitive parameter. The utility of this quick inspection method is verified by the measurement of a solder voids ratio based on the most commonly used approaches in the industry—x-ray. The proposed method is cost effective and only needs around 1–5 s for each LED, which is about one third of the x-ray. Therefore, the quick electrical test method is both meaningful and promising especially when carrying out quality tests on large quantities of solder and can be a highly recommended method to be adopted by the LED lighting industry.

Damage sensing and fracture detection of CNT paste using electrical resistance measurements

The damage sensing properties of carbon nanotube (CNT) paste were investigated as an easy means of detecting cracking. 1wt% CNT paste was fabricated with different epoxy formulations and hardeners (amino and polyamide types) for use in stress sensing tests. The inherent properties of epoxy resins with the different hardeners were compared for different CNT paste applications. An electrical resistance test method was used to evaluate the state of dispersion of the CNT in the epoxy matrices. In the damage sensing tests, 30wt% CF/PP composites were used as the base materials because the polypropylene (PP) has a low crack resistance. In the damage sensing tests an artificial crack was introduce first in the 30wt% CF/PP composites. Then this crack was filled with CNT paste for the evaluation of crack extension and fracture. It was observed that when fracture occurred at the interface between CF/PP composite and the CNT paste the electrical resistance of the test specimen underwent a sudden jump. The changes in electrical resistance facilitated the detection of fracture and crack extension in the CF/PP composites. Additionally, layers of CNT paste was spread on CF/PP composite specimen at three different locations. As these specimens were tested in tension the location of damage in the in the CF/PP composites could also be identified by following the changes in electrical resistance. CNT paste was feasible to repair crack region by blunting due to the stress transfer through crack interface. The tests revealed that CNT pastes based on amino type epoxy was better for this damage detection than the polyamide type, at least in part due to its enhanced dispersion.

A Built-in Test Circuit for Electrical Interconnect Testing of Open Defects in Assembled PCBs

In this paper, a built-in test circuit for an electrical interconnect test method is proposed to detect an open defect occurring at an interconnect between an IC and a printed circuit board. The test method is based on measuring the supply current of an inverter gate in the test circuit. A time-varying signal is provided to an interconnect as a test signal by the built-in test circuit. In this paper, the test circuit is evaluated by SPICE simulation and by experiments with a prototyping IC. The experimental results reveal that a hard open defect is detectable by the test method in addition to a resistive open defect and a capacitive open one at a test speed of 400 kHz.

Modified electrical conductivity test method for evaluation concrete permeability

Standard test method for bulk electrical conductivity (ASTM C1760) provides a rapid indication of the concrete's resistance to the penetration of chloride ions by diffusion. In this paper a new approach for assessing the bulk electrical conductivity of saturated specimens of hardened concrete is presented. The test involves saturating concrete specimens with a 5 M NaCl solution before measuring the conductivity of the samples. By saturating specimens with a highly conductive solution, they showed virtually the same pore solution conductivity. Different concrete samples yield different conductivity primarily due to differences in their pore structure. The feasibility of the method has been demonstrated by testing different concrete mixtures consisting ordinary and blended cement of silica fume (SF) and calcined perlite powder (CPP). Two standard test methods of RCPT (ASTM C1202) and Bulk Conductivity (ASTM C1760) were also applied to all of the samples. The results show that for concretes containing SF and CPP, the proposed method is less sensitive towards the variations in the pore solution conductivity in comparison with RCPT and Bulk Conductivity tests. It seems that this method is suitable for the assessment of the performance and durability of different concretes containing supplementary cementitious materials.

Effect of argon ion energy on the performance of silicon nitride multilayer permeation barriers grown by hot-wire CVD on polymers

Permeation barriers for organic electronic devices on polymer flexible substrates were realized by combining stacked silicon nitride (SiNx) single layers (50nm thick) deposited by hot-wire chemical vapor deposition process at low-temperature (~100°°C) with a specific argon plasma treatment between two successive layers. Several plasma parameters (RF power density, pressure, treatment duration) as well as the number of single layers have been explored in order to improve the quality of permeation barriers deposited on polyethylene terephthalate. In this work, maximum ion energy was highlighted as the crucial parameter making it possible to minimize water vapor transmission rate (WVTR), as determined by the electrical calcium test method, all the other parameters being kept fixed. Thus fixing the plasma treatment duration at 8min for a stack of two SiNx single layers, a minimum WVTR of 5×10−4g/(m2day), measured at room temperature, was found for a maximum ion energy of ~30eV. This minimum WVTR value was reduced to 7×10−5g/(m2day) for a stack of five SiNx single layers. The reduction in the permeability is interpreted as due to the rearrangement of atoms at the interfaces when average transferred ion energy to target atoms exceeds threshold displacement energy.

To Explore the Enclosed Line 330 kV Transformer Preventive Test Method of GIS

本文对封闭式GIS出线变压器的连接结构进行分析、实践，探索出不拆除封闭气管道和高压引线的试验方法，取得表征封闭式变压器健康状态的实际数据，对试验数据分析判断，并与交接试验、同类设备试验数据进行对比，进而验证了方法的正确性和可靠性。结果表明采用的试验方法，在封闭式变压器的绝缘技术监督中能发挥很好地实用性，可以定期开展变压器的预防性试验和异常情况下的检查试验，是一种有效的电气试验方法。 This paper analyzes and practices the connection structure of the closed GIS line transformer and explores the experimental method of not dismantling closed gas pipelines and high voltage wires. The practical data for the health status of the closed type transformer are obtained. The paper analyzes and judges test data and compares test data with the data of commissioning tests and similar equipment tests. Then, it verifies the correctness and the reliability of the method. The results show that the test method used in the insulation technical supervision of the enclosed transformer can play a very good practicality. The preventive test of transformers and check tests in the abnormal situation can be carried out regularly. It is an effective electrical test method.

Electrical properties of fly ash and its decarbonization by electrostatic separation

The basic principle of fly ash triboelectrification is analysed. The mineral electrical index and test method are introduced. The electric difference of different mineral composition of fly ash is discussed by analysis of chemical and mineral composition of fly ash in Xinwen power plant. The dielectric constant and charge–mass ratio of carbon and ash of fly ash are tested. Combined with the experimental study on rotary triboelectrostatic separation, the charged characteristic of fly ash particles with different size is gained. The results show that the dielectric constant of fly ash with different grain size decreased with the decrease of particle size, which lead to the poor electrical conductivity. Thus it can be seen that particle size plays a leading role in conductivity. The charge of carbon and ash with each size increased with the decreased of particle size; and the charge–mass ratio between carbon and ash with the same size larger with the decrease of size, which indicated that the finer particle size, the more favorable for triboelectrification separation. In the same conditions, the best decarburization effect is realized when the particle size ranges from 0.038 to 0.074mm, whose decarbonization rate and efficiency index reached 38.93% and 120.83% respectively.

Design and Implementation of Self-Learning Electrical Measurement System

Through the electrical parameters measurement technology of autonomic learning, understanding of the system hardware by regulating circuit, data acquisition card and computer. This paper, by learning to solve the traditional electrical parameters test method of testing process is not continuous, dynamic transient state is difficult to send now and positioning problem. Virtual instrument measuring instrument is based on the computer, it has many advantages compared with traditional instrument, has been developing rapidly in recent years. The system finished the electrician experiment of common electrical parameters such as: voltage, electric current; Dc voltage, electric current; a measure of the resistance, capacitance and inductance.

The Technical Problems of Discrete Embedded Technology

Discrete embedded technology is one of miniaturization technologies, it can save places for 3D structure, which is suitable and supporting for higher density of electrical components in PCB/substrate, and improve the electrical performance by shorten the distance of interconnection between components and reduce parasitic impedance. However there are still some problems need to be solved, for example: the type of embedded components; the design rules; the process technology; the electrical test method and etc. Some key technical problems and solutions have been given in this article for reference.

A simple electrical test method to isolate viscoelasticity and creep in capacitive microelectromechanical switches

A bipolar hold-down voltage was used to study mechanical degradation in radio-frequency microelectromechanical capacitive shunt switches. The bipolar signal was used to prevent the occurrence of dielectric charging and to isolate mechanical effects. The characteristics of material stress relaxation and recovery were monitored by recording the change of the pull-in voltage of a device. The creep effect in movable components was saturated by repeated actuation to the pulled-in position, while comparison with a theoretical model confirmed the presence of linear viscoelasticity in the devices.

Thermal Stability of High-Power LEDs Analyzed With Efficient Nondestructive Methodology

With the continuing advancement in light-emitting efficiency of high-power light-emitting diodes (LEDs), a nondestructive evaluation on thermal reliability, especially regarding the operating temperature and thermal resistance, which directly affect their lifetime and luminous characteristics, is needed. In this paper, we develop a methodology of using a 3-D numerical simulation for transient thermal-conduction analysis, which is combined with the electrical test method to evaluate the junction temperature of a variety of LEDs. As a result, the simulated temperature for LEDs was found to increase with time, whereas the slug temperature showed the same trend for the simulation and the experiment. The measured results indicate that the thermal resistance of AlGaInP-material-based red and amber LEDs reveals higher variability than that of InGaN-material-based white and green LEDs. Via the luminous flux experiment, we have found that the thermal resistance of the LEDs is not the major determination factor of their luminous flux decay. In contrast, the luminous flux decay of the LED is dependent on the chip material being used. Notably, the slug temperature, observed from the pulsed-driven experiment, of the LED appeared to be lower than that observed in the normal steady operation. It is demonstrated that the lifetime and reliability of high-power LEDs can be improved by decreasing the junction and slug temperatures of the devices. This is important as the slug temperature can be controlled by external cooling techniques. In practice, the developed methodology is not restricted to analyze particular LED packaging forms and can be used to investigate various kinds of multichip LED modules as well.

Experiment Research on Tensile-Shear Behavior of Spot-Welded Lap Joints of Ultra-High Strength Steel with Common Steel

The welding spot of Ultra-high strength steel of 22MnB5 and common steel of St16 were the investigative objects, the intermediate frequency inverter & electric servo welding system was used to weld the sheets. Electrical measuring test method was used on spot-welded joint under tensile-shear load to determinate the strain of different positions, including the strain of weld nugget, the stain around the nugget and the base metals strain near the weld nugget. The deformation regularity of spot welding joints surrounding and base metal were analysed according to the data. The test provided a reference for the numerical simulation of spot welding model. Test results show that the strain distribution on spot welding joint is not uniform, the strain of the weld nugget center is relatively small, large deformation exists mainly in the heat affected zone. That is to say, the area near the spot-welding joint heat affected zone is prone to yield. The base metal area near the weld nugget is mainly affected by tensile strain, and the strain increases with the increasing of the load. The force condition of the specimen is complicated around the nugget, the relationship between the load and the strain is erratic. The strain of the weld nugget will gradually change from axial compressive strain to axial tensile strain. The strain of spot welding specimen made of dissimilar materials (22MnB5& ST16) is negative, and almost linearly.

Evaluation of the sensitivity limits of water vapor transmission rate measurements using electrical calcium test

The development of flexible organic light emitting diode displays and flexible thin film photovoltaic devices is dependent on the use of flexible, low-cost, optically transparent and durable barriers to moisture and∕or oxygen. It is estimated that this will require high barriers with water vapor transmission rates (WVTR) between 10(-4) and 10(-6) g∕m(2)∕day. Thus, there is a need to develop a relatively fast, low cost, and quantitative method to evaluate such low permeation rates. Prior works have demonstrated that Ca films, because they change optically and electrically upon reaction with moisture, can be used as a sensor, enabling one to calculate a WVTR between 10 and 10(-6) g∕m(2)∕day or better. In this work, we analyze the accuracy of an electrical Ca test method. We focus on the effects of the addition of a diffusion spacer and the effects of interactions of edge-seal material with changes to the spacer contacting surface on the overall accuracy. Furthermore, we examine a series of factors that can lead to different errors resulting in qualitative rather than quantitative Ca test behavior. We demonstrate that accurate, relatively high throughput, and reproducible measurements are possible for very low WVTR films in the 10(-6) g∕m(2)∕day range.