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15 Cards in this Set
- Front
- Back
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What is the characteristic of an electrical circuit that opposes change in current?
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Inductance
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What is the process by which a circuit induces an emf into itself by its own moving magnetic field?
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Self-inductance
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What are the two normal types of core material for an inductor?
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Air or soft iron
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What happens to inductance when the diameter and number of turns in a coil are increased?
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Inductance increases
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For practical purposes, the current in an inductor reaches maximum value in how many time constants?
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5
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What is the formula for measuring copper loss?
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I2R
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What is the phase relationship between current and voltage in an inductor?
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Current lags voltage by 90 degrees (ELI)
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What is the formula for inductive reactance(XL)?
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XL= 2πfL
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How does a capacitor affect voltage in a circuit?
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Opposes any change in voltage
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What is the formula for capacitive reactance (XC)?
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XC= 1
2πfC |
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What term is used to describe the opposition to alternating current?
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Impedance
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The number of degrees that current leads or lags voltage in an AC circuit.
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Phase angle
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What two formulas derived from Ohm's law are used in AC circuits?
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E = IZ, I = E/Z
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What is the power returned to the source by the reactive elements of a circuit?
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Reactive power
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What is the power that appears to the source because of circuit impedance?
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Apparent power
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