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Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
Volterra integral equation a linear integral equation wherein the limits of integration are functions of position. Volterra series a series expansion of a nonlinear function around a point. The Volterra series method is a generalization of the power-series method useful for analyzing harmonic and intermodulation distortion due to frequency-dependent nonlinearities in a device. voltmeter an instrument for measuring a potential difference between different points of an electrical circuit. Units are volts. volts/hertz control a method of speed control of induction machines, used below rated speed. When the volts/hertz ratio is kept constant, the current through the stator windings remains almost the same, except for very low speeds; hence, the available torque remains constant, but the speed changes due to change in frequency. volume plasmon plasma medium. a volume polariton in a
Energy Audit
Published in Anil Kumar, Om Prakash, Prashant Singh Chauhan, Samsher, Energy Management, 2020
Anil Kumar, Om Prakash, Prashant Singh Chauhan, Samsher
These are devices used for taking measurements of parameters such as kVA, kW, PF, Hertz, kVAr, Amps and Volts, and also harmonics. An ammeter is used for measuring the electric current denoted by symbol amperes (A). A voltmeter is used to measure electrical potential differences across any two points in a circuit. Analog voltmeter uses pointer which moves across a scale in proportion to the voltage of the circuit, whereas digital voltmeters have a numerical display and digital converter.
V
Published in Splinter Robert, Illustrated Encyclopedia of Applied and Engineering Physics, 2017
[electromagnetism, general] Galvanometer in series with a resister with the primary purpose of measuring the electrical potential between two points. The resistance is chosen to provide the idealized conditions of zero current, in order to prevent influencing the charge storage on the device being measured for voltage difference. Generally, the voltmeter is integrated in a multifunctional device that can measure current, voltage, and resistance called a multimeter (see Figure V.44).
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 sample used in the experiments was a round glass pane with a radius of ~15 mm and a thickness of ~1 mm. The average roughness of the sample was 0.965 nm, and the root-mean-square roughness was 1.668 nm (see Supplementary Figure S1). Before the experiments, the sample was coated with a First Contact polymer (Photonic Cleaning Technologies, Platteville, Wisconsin), an inert, non-toxic polymer to remove contaminants from surfaces without scratching or damage. Then, the layer was peeled off with tweezers, and the sample surface was net negatively charged (see Supplementary Figures S2(a-c)). The electrostatic surface voltage of the sample was determined using a hand-held electrostatic voltmeter (Trek Model 520, Trek Inc., Lockport, New York, USA). The measurement range of this voltmeter is 0 ~ ±2000 kV DC with an accuracy better than ±5% of full scale over a separation range of 5 ~ 25 mm. During the measurements, the sample was backed by a large grounded metal plane, and the grounded terminal of this voltmeter was also connected to the plane (see Supplementary Figure S2(d)). More than 10 locations were selected to measure surface voltage, and then a mean value was obtained. If necessary, surface charges on the sample can be eliminated by establishing a field of ionized air using a static ionizer (SY-988A, Shenzhen Shengyuan Anti-Static Corporation, Guangdong, China).
Experimental analysis on passive cooling of flat photovoltaic panel with heat sink and wick structure
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020
Parkunam N, Lakshmanan Pandiyan, Navaneethakrishnan G, Arul S, Vijayan V
The numbers represent the sensor points. The positive and negative represents the output points from the panel. The voltmeter is connected in parallel for voltage measurement. The ammeter is connected in series for current measurement. The various loads are connected to measure the zero current and maximum voltage.