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Response to Low-Frequency Alternating Current Passing Through the Body
Published in Leslie A. Geddes, Handbook of Electrical Hazards and Accidents, 1995
The term leakage current is used to identify an undesired current flowing through a subject from a power-line operated device. To understand how leakage current arises, it is useful to recall that domestic power outlets have three terminals and that one side of the power line is grounded. Figure 3.10 illustrates the conventional wiring of the standard (single-phase) 3-prong receptacle which accepts a plug with two blades and a rod. The “hot” or ungrounded side of the power line is color-coded black, the return or “cold” grounded conductor is color-coded white. Current is delivered to a device (R) connected to these two conductors as shown in Figure 3.10. Power current is never conducted by the green or grounding conductor connected to the circular opening on the receptacle; this connection serves to ground the metal housing of a device plugged into the three-conductor receptacle.
Solar Energy
Published in Bella H. Chudnovsky, Transmission, Distribution, and Renewable Energy Generation Power Equipment, 2017
Evaluation of the environmental conditions that influence the system PID mechanisms is done in Refs. [9,10]. It was shown that the wet module associated with the morning dew or rains leads to an elevated leakage current as the system voltage rises with the sun. The leakage current decreases significantly when the module dries and the surface resistance increases. Despite that conductivity of glass and encapsulating material increases with temperature, the leakage current remains controlled by humidity. It is therefore concluded that a wet environment will activate system voltage degradation mechanisms more than a hot, dry environment based on the elevated leakage current.
Advanced Power Management Methodology for SoCs Using UPF
Published in Durgesh Nandan, Basant K. Mohanty, Sanjeev Kumar, Rajeev Kumar Arya, VLSI Architecture for Signal, Speech, and Image Processing, 2023
Usha Rani Nelakuditi, Naveen Kumar Challa, Kurra Anil Kumar
Currently, many real time electronic appliances like mobiles, wireless network interfaces require low power consumption to sustain for a longer time. There are many techniques developed during the last 10 years to satisfy the power requirements of SoCs and ASICs [5]. Performance of chip also affects the power consumption. Enhanced speed of operation of electronic devices increases the power consumption of the chip, since dynamic power is directly proportional to the frequency of operation. Though static power consumption is zero for CMOS devices, due to scaling there exist reverse leakage currents of drain and gate and short cannel, subthreshold and hot carrier injection (HCI) currents, etc., plays a vital in high density chip. Leakage currents can be reduced by reducing the supply voltage for proper operation. The major component of power dissipation in CMOS is dynamic power which is due to device and load conduction and signal switching. This dynamic power can be reduced by reducing the switching transitions and adjusting the operational frequency. The above stated issues lead to the proper design of CMOS low power and low voltage methodologies. SoCs with these features enhances the complexity. Moreover, life of the battery depends upon the power drawn by the system. Hence power consumption of chip should be kept within the acceptable limits to enhance the life of the devices. In this section few important methods such as substrate biasing, “clock gating, multi-switching (multi-Vt) threshold transistors, dynamic voltage and frequency scaling (DVFS), and unified power format (UPF)” [2], voltage scaling, up to sub one volt and RTL-based techniques are explained to reduce static and dynamic power.
Evolution of millimetric-range electrostatic forces between an AFM cantilever and a charged dielectric via suspended force curves
Published in The Journal of Adhesion, 2022
Tianmao Lai, Mingli Guo, Yuguo Chen
The decrease in long-range force after the maximum was attributed to surface charge decay. As shown in (Figure 5(f,g)), with the dissipation of surface charges, the charge density on the sample and corresponding electric intensity will decrease, and the electric quantity of positive charges accumulated at the free end of the cantilever will also decrease due to carrier drift. Both of these will lead to a decrease in long-range force. However, electric charges on the sample surface will remain over a long time determined by decay efficiency. The decrease in long-range force is a very slow and time-consuming process. In the literature, the surface charge decay can occur due to three main mechanisms: (1) gas neutralization by ions present in the air, (2) surface conduction, (3) bulk neutralization.[35–37] The decay rate is dependent on the material nature, surface condition, type of ambient gas and temperature, and so on.[38] In the gas neutralization, free ions in the air due to several background ionization processes are attracted to the charged sample surface.[35] In the mechanism of surface conduction, charge leakage occurs along the sample surface due to the potential gradient with unevenly distributed charge. The leakage current is quantified by surface conductivity, depending on field intensity, pollution and relative humidity.[39] This mechanism may be negligible due to the low field and relative humidity in the experiments.
A 100-Mrad (Si) JFET-Based Sensing and Communications System for Extreme Nuclear Instrumentation Environments
Published in Nuclear Technology, 2022
F. Kyle Reed, M. Nance Ericson, N. Dianne Bull Ezell, Roger A. Kisner, Lei Zuo, Haifeng Zhang, Robert Flammang
Ionizing radiation is largely responsible for electronics degradation in dry spent fuel casks. Electronic damage from ionization produced by high-energy photons creates free charge carriers (electrons and holes) in the atomic conduction and valence electron bands of materials through the photoelectric effect, Compton scattering, and pair creation.6 The generation of free charge carriers increases the conductivity and therefore increases leakage currents. In insulators (i.e., materials with low concentrations of free charge carriers), the bandgap energy is much larger than conductors and semiconductors, which have high or moderately high concentrations of free charge carriers, respectively. Due to insulators’ wide bandgap energies, electrons are commonly trapped in the forbidden bandgap in a phenomenon called charge trapping. Charge traps can accumulate and give rise to large electric fields within insulating materials and between them and surrounding conductors. The presence of these large electric fields influences the operation of field-effect devices and can lead to dielectric breakdowns.
Revived tungsten bronze ceramic for thermistor and RAM devices
Published in Phase Transitions, 2020
B. N. Parida, S. Behera, R. Padhee, Piyush R. Das
Figure 3(e,f) represents the spectral distribution of Z″ at different temperature ranges. In both the graphs it is observed that the value of Z″ increases with the increase of frequency at different temperatures and achieves a peak value at temperature ≥ 350°C. This suggests that the material requires relaxation during the activation of charge carriers. The frequency at which Z″ attains a maximum is usually referred to as relaxation frequency whose reciprocal is referred to as relaxation time. It is also observed that the relaxation time decreases with the rise of temperature which suggests charge carriers involved in the relaxation process needs less relaxation as temperature increases. This can be explained as charge carriers get a boost of energy from the supplied temperature which, in turn, helps in the increase of the conduction phenomena (leakage current) of the material. It is also noticed in Figure 3(e,f) that, FWHM of loss impedance spectra are temperature dependent i.e. (increases with temperature). This behaviour in the studied sample confirms its leakage property which increases due to th activation of oxygen vacancies or defects at higher temperature.