Delmars Unit 24 Resistive-Inductive-Capacitive Parallel Circuits
An RLC parallel circuit has an applied voltage of 240 volts. R = 60 Ω, XL = 20 Ω, and XC = 36 Ω. What is the capacitive current? 6.67 A 5 A 4 A 3.27 A
6.67 A
An RLC parallel circuit has an applied voltage of 240 V. R = 60 Ω, XL = 80 Ω, and XC= 40 Ω. What is the apparent power? 1400 VA 1440 VA 300 VA 1200 VA
1200 VA
An RLC parallel circuit has an applied voltage of 240 volts. R = 64 Ω, XL = 120 Ω, and XC = 180 Ω. What are the VARsL? 480 520 900 960
480
If an RLC parallel circuit contains more inductive VARs than capacitive VARs, the circuit has a _____ power factor. lagging leading
lagging
A parallel tank circuit operating at its resonant frequency has an impedance of 10,000 Ω. At the points on either side of the resonant frequency that define the bandwidth, the impedance is approximately _____. 10,140 Ω 7,070 Ω 15,000 Ω 6,000 Ω
7,070 Ω
The current flowing through a pure resistive element in an RLC parallel circuit will be in phase with the applied voltage. True False
True
When values of inductive reactance and capacitive reactance become equal, they are said to be resonant. False True
True
Which of these formulas is used to calculate apparent power?
VA=
If the power factor is corrected exactly so that the circuit is purely resistive, the power factor has a value of _____. 0.95 50% unity zero
0.95
A parallel circuit at resonance has ITANK = 1.00 A, ILINE = 0.05 A, Q = 20, and a voltage across the tank of 500 V. What is the impedance of the tank? 25,000 Ω 50,000 Ω 70,000 Ω 10,000 Ω
10,000 Ω
An RLC parallel circuit has an applied voltage of 208 volts. R = 68 Ω, XL = 87 Ω, and XC = 81 Ω. What are the VARsC? 721.67 436.24 534.12 697.29
534.12
An RLC parallel circuit has an applied voltage of 240 volts. R = 48 Ω, XL = 100 Ω, and XC = 36 Ω. What is the total current? 7 A 9.67 A 8.4 A 6.57 A
6.57 A
The current flowing through a pure inductive element leads the applied voltage by 90 electrical degrees. True False
False
Which of these formulas is used to calculate inductive current?
IL
Which of these formulas is used to calculate resistive current?
IR=
Which of these formulas is used to calculate parallel resonance?
Q=
LC parallel circuits are often referred to as _______________ circuits
Tank
In an RLC parallel circuit, the phase angle difference between the applied voltage and the total current is determined by the ratio of resistance, inductance, and capacitance connected in parallel. True False
True
The impedance of an RLC parallel circuit is the reciprocal of the sum of the reciprocals of the legs. True False
True
Which of these formulas is used to calculate inductive VARs?
VarsL=
An RLC series circuit has a 60-Hz, 120V applied voltage. R = 75 Ω, XL = 100 Ω, and XC = 89 Ω. What is the circuit capacitance? 29.80 μF 16.53 μF 909 μF 25.37 μF
29.80 μF
When calculating values in an RLC parallel circuit, what does VARSC represent? apparent power of the inductor reactive power of the inductor apparent power of the capacitor reactive power of the capacitor
reactive power of the capacitor
An RLC parallel circuit has an applied voltage of 240 volts. R = 48 Ω, XL = 100 Ω, and XC = 36 Ω. What is the circuit impedance (Z)? 17.06 Ω 110.92 Ω 80 Ω 64.22 Ω
64.22 Ω
IR represents current flow through the inductor. False True
False
The current flowing through a pure capacitive element will lag the voltage by 90 electrical degrees. True False
False
Which of these formulas is used to calculate capacitive current?
IC=
Which of these formulas is used to calculate inductance?
L=
For parallel resonant circuits, the correct formula relating ITANK, Q, and ILINE is _____. ITANK = ILINE / Q ILINE = Q × ITANK ITANK = Q / ILINE Q = ITANK / ILINE
Q = ITANK / ILINE
Which of these formulas is used to calculate capacitive VARs?
VarsC
To correct the power factor to 100%, an equal amount of capacitive VARs would be connected in _____ with the motor. parallel series
parallel
When an AC circuit contains elements of resistance, inductance, and capacitance connected in parallel, what is the voltage dropped across each element? equal to applied voltage the same less than true power greater than true power
the same
In an RLC parallel circuit, the _____ is the same through all components and the _____ are out of phase. voltage; currents current; voltages
voltage; currents
An RLC parallel circuit has an applied voltage of 208 volts. R = 42 Ω, XL = 52 Ω, and XC = 18 Ω. What is the inductive current? 3.85 A 3.92 A 4 A 4.52 A
4 A
An RLC parallel circuit has an applied voltage of 240 volts. R = 60 Ω, XL = 100 Ω, and XC = 32 Ω. What is the resistive current? 6 A 3.5 A 5.4 A 4 A
4 A
An RLC parallel circuit has an applied voltage of 240 V. R = 48 Ω, XL = 100 Ω, and XC = 36 Ω. What is angle theta? 34.36° 53.13° 26.87° 40.48°
40.48°
An RLC parallel circuit has an applied voltage of 277 volts. R = 82 Ω, XL = 50 Ω, and XC = 124 Ω. What is the true power? 694.67 W 753.58 W 935.72 W 1018.78 W
935.72 W
Which of these formulas is used to calculate total circuit current?
IT=
Which of these formulas is used to calculate true power produced by the coil?
P=
Which of these formulas is used to calculate watts?
P=
Which of these formulas is used to calculate capacitive reactance?
XC
In a parallel LC circuit, the difference in frequencies above and below resonance at which impedance is 0.707 of the maximum is called the _____ of the circuit. Q bandpass bandwidth resonance
bandwidth
An RLC parallel circuit has an applied voltage of 208 V. R = 68 Ω, XL = 87 Ω, and XC= 81 Ω. What is the power factor? 0.277 0.212 0.004 0.337
0.337
An RLC series circuit has a 60-Hz, 120V applied voltage. R = 50 Ω, XL = 137 Ω, and XC = 160 Ω. What is the inductance in the circuit? 0.424 H 0.363 H 0.133 H 0.261 H
0.363 H
When calculating values in an RLC parallel circuit, what does IL represent? current flow through the inductor current flow through the resistor current flow through the capacitor total circuit current
current flow through the inductor
If an RLC parallel circuit contains more capacitive VARs than inductive VARs, the circuit has a _____ power factor. leading lagging
leading
