Phase rotation defines the rotation in a Poly-Phase System and is generally stated as "1-2-3", counterclockwise rotation. The angular displacement between a current and voltage waveform, measured in degrees or radians. ![]() The amplitude of the ac wave form from its positive peak to its negative peak. The terminals of a diode are called the anode and cathode. The function of a diode is to allow current in one direction and to block current in the opposite direction. Diode:Ī two-terminal semiconductor (rectifying) device that exhibits a nonlinear current-voltage characteristic. The ability of insulating materials and spacings to withstand specified overvoltages for a specified time (one minute unless otherwise stated) without flashover or puncture. A voltage is applied of a specific magnatude for a specific period of time. Dielectric Test:Ī test that is used to verify an insulation system. Dielectric Constant:Ī number that describes the dielectric strength of a material relative to a vacuum, which has a dielectric constant of one. 2) The medium used to provide electrical isolation or separation. Dielectric:ġ) Any electrical insulating medium between two conductors. The higher the dBm, the higher the devices transmit or receive power. A power ratio of 10 to 1 is not 20dB, but 10dB, since power(P) is proportional to the square of voltage(V). A voltage ratio of 1 to 10 is equal to -20dB, 10 to 1 to 20dB, 100 to 1 to 40dB and 1000 to 1 to 60dB. Decibel (dB):Ī unit used to express the magnitude of change in level of electric signal or sound intensity. 2) Current that flows in one direction only. Crest factor = Maximum value/True RMS value For sinusoidal wave Crest factor = 141/100 = 1.41ġ) Direct current. It represents the range of input in which a tester maintains linear operation, expressed by a multiple of the full scale value of the range being used. The ratio of the maximum value to the effective value. Creepage Distance is normally a design parameter of insulators or insulating bushings. The shortest distance between two conductors as measured along the device that separates them. 2) Any material that allows electrons to flow through it. The capability of a conductor to carry electricity, usually expressed as a percent of the conductivity of a same sized conductor of soft copper Conductor:ġ) A wire or combination of wires suitable for carrying an electrical current. International Commission on Rules for the Approval of Electrical Equipment A regional, European safety agency in which the United States participates only as an observer. Cathode:ġ) The negative electrode, that emits electrons or gives off negative ions and toward which positive ions move or collect in a voltaic cell or other such device. Capacitor:Īn electrical device having Capacitance. 3) The property of being able to collect a charge of electricity. 2) The ratio of the charge on either conductor of a capacitor to the potential difference between the conductors. Capacitance:ġ) The ratio of an impressed charge on a conductor to the corresponding change in potential. Apparent power, or volt-amps, is not the true power of the circuit because the power factor is not considered in the calculation.Īdjustment of a device so the output is within a specified range for particular values of the input. The product of the applied voltage and current in an ac circuit. Ampère-hour meter:Īn electricity meter that measures and registers the integral, with respect to time, of the current of a circuit in which it is connected. ![]() One Ampère is the current produced by a difference in potential of one volt across a resistance of one ohm An electic current flowing at therate of one coulomb per second. The unit expressing the rate of flow of an electric current. Active Power:Ī term used for power when it is necessary to distinguish among Apparent Power, Complex Power and its components, and Active and Reactive Power. Dgt indicates the counts on the last significant digit of the digital display and is typically used to represent an error factor of a digital tester. "Rdg"is for reading and "dgt"is for digits. The second portion is an error, in digits, that is constant regardless of the input. Accuracy is specified in the format: (±xx% rdg ±xx dgt) The first portion identifies a percentage error relative to the reading, which means it is proportional to the input. The accuracy of a digital tester is defined as the difference between the reading and the true value for a quantity measured in reference conditions. ![]() Fluke virtual demos and product selectors.
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