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12 Cards in this Set
- Front
- Back
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What effect does an inductor have on a change in current?
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An inductor opposes a change in current.
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What is the phase relationship between current and voltage in an inductor?
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Current lags voltage by 90º (ELI).
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What effect does the capacitor have on a changing voltage?
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The capacitor opposes any change in voltage.
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What is the phase relationship between current and voltage in a capacitor?
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Current leads voltage by 90º (ICE).
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What term is given to total opposition to ac in a circuit?
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Impedance.
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What is the true power in an ac circuit?
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True power is the power dissipated in the resistance of the circuit or the power actually used in
the circuit. |
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What is the unit of measurement of true power?
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Watt.
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What is the formula for calculating true power?
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True Power = (IR) 2R.
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What is the difference between calculating impedance in a series ac circuit and in a parallel ac
circuit? |
In a series circuit impedance is calculated from the values of resistance and reactance. In a
parallel circuit, the values of resistive current and reactive current must be used to calculate total current (impedance current) and this value must be divided into the source voltage to calculate the impedance. |
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An inductor in an ac circuit opposes any change in current
flow just as it does in a dc circuit. |
INDUCTANCE IN AC CIRCUITS
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The current lags the voltage by 90º in an
inductor (ELI). |
PHASE RELATIONSHIPS OF AN INDUCTOR
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The opposition an inductor offers to ac is called inductive
reactance. It will increase if there is an increase in frequency or an increase in inductance. The symbol is XL, and the formula is XL = 2πfL. |
INDUCTIVE REACTANCE
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