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University Physics Volume 2

Key Terms

University Physics Volume 2Key Terms

Key Terms

ac current
current that fluctuates sinusoidally with time at a fixed frequency
ac voltage
voltage that fluctuates sinusoidally with time at a fixed frequency
alternating current (ac)
flow of electric charge that periodically reverses direction
average power
time average of the instantaneous power over one cycle
bandwidth
range of angular frequencies over which the average power is greater than one-half the maximum value of the average power
capacitive reactance
opposition of a capacitor to a change in current
direct current (dc)
flow of electric charge in only one direction
impedance
ac analog to resistance in a dc circuit, which measures the combined effect of resistance, capacitive reactance, and inductive reactance
inductive reactance
opposition of an inductor to a change in current
phase angle
amount by which the voltage and current are out of phase with each other in a circuit
power factor
amount by which the power delivered in the circuit is less than the theoretical maximum of the circuit due to voltage and current being out of phase
quality factor
dimensionless quantity that describes the sharpness of the peak of the bandwidth; a high quality factor is a sharp or narrow resonance peak
resonant frequency
frequency at which the amplitude of the current is a maximum and the circuit would oscillate if not driven by a voltage source
rms current
root mean square of the current
rms voltage
root mean square of the voltage
step-down transformer
transformer that decreases voltage and increases current
step-up transformer
transformer that increases voltage and decreases current
transformer
device that transforms voltages from one value to another using induction
transformer equation
equation showing that the ratio of the secondary to primary voltages in a transformer equals the ratio of the number of turns in their windings
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