93 lines
3.7 KiB
Markdown
93 lines
3.7 KiB
Markdown
E5A Resonance and Q: characteristics of resonant circuits; series and parallel resonance; definitions and effects of Q; half-power bandwidth
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- [[E5A01]] (A)
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What can cause the voltage across reactances in a series RLC circuit to be higher than the voltage applied to the entire circuit? #card
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- [[A.]] Resonance
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- [[B.]] Capacitance
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- [[C.]] Low quality factor (Q)
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- [[D.]] Resistance
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- [[E5A02]] (C)
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What is the resonant frequency of an RLC circuit if R is 22 ohms, L is 50 microhenries, and C is 40 picofarads? #card
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- [[A.]] 44.72 MHz
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- [[B.]] 22.36 MHz
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- [[C.]] 3.56 MHz
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- [[D.]] 1.78 MHz
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- [[E5A03]] (D)
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What is the magnitude of the impedance of a series RLC circuit at resonance? #card
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- [[A.]] High, compared to the circuit resistance
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- [[B.]] Approximately equal to capacitive reactance
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- [[C.]] Approximately equal to inductive reactance
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- [[D.]] Approximately equal to circuit resistance
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- [[E5A04]] (A)
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What is the magnitude of the impedance of a parallel RLC circuit at resonance? #card
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- [[A.]] Approximately equal to circuit resistance
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- [[B.]] Approximately equal to inductive reactance
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- [[C.]] Low compared to the circuit resistance
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- [[D.]] High compared to the circuit resistance
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- [[E5A05]] (A)
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What is the result of increasing the Q of an impedance-matching circuit? #card
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- [[A.]] Matching bandwidth is decreased
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- [[B.]] Matching bandwidth is increased
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- [[C.]] Losses increase
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- [[D.]] Harmonics increase
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- [[E5A06]] (B)
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What is the magnitude of the circulating current within the components of a parallel LC circuit at resonance? #card
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- [[A.]] It is at a minimum
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- [[B.]] It is at a maximum
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- [[C.]] It equals 1 divided by the quantity 2 times pi, times the square root of (inductance L multiplied by capacitance C)
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- [[D.]] It equals 2 times pi, times the square root of (inductance L multiplied by capacitance C)
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- [[E5A07]] (A)
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What is the magnitude of the current at the input of a parallel RLC circuit at resonance? #card
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- [[A.]] Minimum
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- [[B.]] Maximum
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- [[C.]] R/L
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- [[D.]] L/R
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- [[E5A08]] (C)
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What is the phase relationship between the current through and the voltage across a series resonant circuit at resonance? #card
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- [[A.]] The voltage leads the current by 90 degrees
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- [[B.]] The current leads the voltage by 90 degrees
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- [[C.]] The voltage and current are in phase
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- [[D.]] The voltage and current are 180 degrees out of phase
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- [[E5A09]] (C)
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How is the Q of an RLC parallel resonant circuit calculated? #card
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- [[A.]] Reactance of either the inductance or capacitance divided by the resistance
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- [[B.]] Reactance of either the inductance or capacitance multiplied by the resistance
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- [[C.]] Resistance divided by the reactance of either the inductance or capacitance
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- [[D.]] Reactance of the inductance multiplied by the reactance of the capacitance
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- [[E5A10]] (A)
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What is the resonant frequency of an RLC circuit if R is 33 ohms, L is 50 microhenries, and C is 10 picofarads? #card
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- [[A.]] 7.12 MHz
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- [[B.]] 23.5 kHz
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- [[C.]] 7.12 kHz
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- [[D.]] 23.5 MHz
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- [[E5A11]] (C)
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What is the half-power bandwidth of a resonant circuit that has a resonant frequency of 7.1 MHz and a Q of 150? #card
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- [[A.]] 157.8 Hz
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- [[B.]] 315.6 Hz
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- [[C.]] 47.3 kHz
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- [[D.]] 23.67 kHz
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- [[E5A12]] (C)
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What is the half-power bandwidth of a resonant circuit that has a resonant frequency of 3.7 MHz and a Q of 118? #card
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- [[A.]] 436.6 kHz
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- [[B.]] 218.3 kHz
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- [[C.]] 31.4 kHz
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- [[D.]] 15.7 kHz
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- [[E5A13]] (C)
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What is an effect of increasing Q in a series resonant circuit? #card
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- [[A.]] Fewer components are needed for the same performance
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- [[B.]] Parasitic effects are minimized
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- [[C.]] Internal voltages increase
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- [[D.]] Phase shift can become uncontrolled
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