Deck 17: Rlc Circuits and Resonance

Question 1

Figure 17-1
If the series circuit in Figure 17-1 is resonant, the inductive and capacitive reactance must be equal.

Answer 1

True

Question 2

If the parallel circuit in Figure is resonant, the circuit is purely resistive and the phase shift is zero degrees.

Answer 2

True

Question 3

Resonant frequency of a circuit occurs when the inductive reactance is equal to the capacitive reactance.

Answer 3

True

Question 4

Given the circuit in Figure, the circuit current is:

A) 1 A
B) 198 µA
C) 0.87 mA
D) 100 mA

Question 5

If the parallel circuit in Figure is resonant, the impedance, as seen by the generator will be very high.

Question 6

In a series RLC circuit, above resonance the circuit is more capacitive than it is inductive.

Question 7

A parallel resonant circuit has a low impedance at the resonant frequency.

Question 8

In a series resonant circuit, current is maximum and impedance is minimum at resonance.

Question 9

Figure 17-1
If the series circuit in Figure 17-1 is resonant, the impedance, as seen by the generator will be very high.

Question 10

A parallel tuned circuit can be used to couple energy from one circuit to another.

Question 11

Given the circuit in Figure , the circuit impedance is:

A) 690 Ω
B) 100 Ω
C) 318 Ω
D) 345 Ω

Question 12

If the parallel circuit in Figure is NOT resonant, the impedance will be lower than it is at the resonant frequency.

Question 13

If the parallel circuit in Figure is resonant, increasing the Q will produce a wider bandwidth.

Question 14

Given the circuit in Figure , the circuit impedance is:

A) 5.88 Ω
B) 6.4 Ω
C) 14.46 Ω
D) 8.1 Ω

Question 15

A series resonant circuit has a low impedance at the resonant frequency.

Question 16

Figure 17-1
If the series circuit in Figure 17-1 is resonant, the circuit is purely resistive and the phase shift is zero degrees.

Question 17

If the parallel circuit in Figure is resonant, the inductive and capacitive reactance must be equal.

Question 18

By increasing the resistance of a coil you can increase the Q of the coil at resonance.

Question 19

Figure 17-1
If the series circuit in Figure 17-1 is NOT resonant, the impedance will be lower than it is at the resonant frequency.

Question 20

Figure 17-1
If the series circuit in Figure 17-1 is resonant, increasing the Q will produce a wider bandwidth.

Question 21

Given the circuit in Figure 17-5, the circuit phase angle is:

A) 90°
B) 34.5°
C) -5.4°
D) -1.3°

Question 22

The current through the capacitor in Figure is:

A) 159.7 mA
B) 434 mA
C) 279.65 mA
D) 4.3 A

Question 23

The Circuit impedance in Figure is:

A) 70.5 Ω
B) 7.55 Ω
C) 265 Ω
D) 33 Ω

Question 24

At resonance the power factor is:

A) negative
B) 1
C) M5
D) zero

Question 25

The inductive reactance in Figure is:

A) 2.7 kΩ
B) 750 Ω
C) 2.6 Ω
D) 7.5 Ω

Question 26

At frequencies well above and below the resonant frequency, the series RLC circuit looks above resonance, and the parallel RLC circuit looks below resonance.

A) like an open, like a short
B) like a short, like an open
C) inductive, inductive
D) inductive, capacitive

Question 27

Given the circuit in Figure 17-4, is the circuit mostly inductive or capacitive?

A) capacitive
B) inductive

Question 28

The capacitive reactance in Figure is:

A) 159.7 Ω
B) 26.53 Ω
C) 265.3 Ω
D) 2.7 kΩ

Question 29

The True power in Figure is:

A) 200.7 W
B) 7.5 W
C) 43.29 W
D) 401 W

Question 30

In a series LC circuit, L = 100 µH, C = 0.047 µF, and f = 150 kHz. The value of ZT is:

A) 72 $\Omega \angle$
90°
B) 36 $\Omega \angle$
45°
C) -72 $\Omega \angle$
-90°
D) 72 $\Omega \angle$
-90°

Question 31

The phase shift between the source voltage V_S and total circuit current in Figure is:

A) -46.45°
B) 23.4°
C) -23.4°
D) -76.8°

Question 32

Is the circuit in Figure 17-5, at or very close to resonance?

A) Yes
B) No

Question 33

Apparent power in an RLC circuit is equal to total voltage times total current when:

A) the circuit is not at resonance
B) the circuit is at resonance.
C) it is a series or parallel circuit
D) all of the above

Question 34

The Total circuit current in Figure is:

A) 4.3 A
B) 14.87 A
C) 15.2 A
D) 3.5 A

Question 35

The current through the resistor in Figure is:

A) 459.65 mA
B) 15.9 A
C) 350 mA
D) 3.48 A

Question 36

Given the circuit in Figure 17-5, the circuit current is:

A) 7.64 mA
B) 36.9 mA
C) 0.1 A
D) 3.03 mA

Question 37

The lower and upper end of the band width of a series RLC circuit is where the current has fallen to of the maximum.

A) 70.7%
B) 63.6%
C) 29.3%
D) 50%

Question 38

The current through the inductor in Figure is:

A) 27.9 A
B) 15.3 A
C) 153 mA
D) 1.5 A

Question 39

Given the circuit in Figure , the circuit impedance is:

A) 3.3 kΩ
B) 6.94 kΩ
C) 27.1 kΩ
D) 7.07 kΩ

Question 40

Is the circuit in Figure 17-7 at or near resonance?

A) No
B) Yes

Question 41

In Figure 17-8, calculate VR.

A) 33.9 V 2-58°
B) 95.0 V 2-39°
C) 33.9 V 258°
D) 95.0 V 239°

Question 42

-calculate ZT.

A) 58 $\Omega \angle$
-39°
B) 58 $\Omega \angle$
39°
C) 19.6 $\Omega \angle$
71.4°
D) 19.6 $\Omega \angle$
-71.4°

Question 43

Half-power frequencies

A) determine the pass band.
B) determine bandwidth.
C) determine selectivity.
D) all of the above
E) none of the above

Question 44

In a series LC circuit, VL = 8.3 V and VC = 10.6 V. VS = .

A) -2.3 V 2-90°
B) 8.3 V 2-90°
C) -2.3 V 290°
D) 2.3 V 2-90°

Question 45

The center frequency of a band-pass filter is always equal to the .

A) geometric mean average of the cutoff frequencies
B) 3-dB frequency
C) bandwidth divided by Q
D) bandwidth

Question 46

In Figure 17-8, calculate IT.

A) 157 A 2-71.4°
B) 464 A 2-39°
C) 157 A 271.4°
D) 464 A 239°

Question 47

In Figure 17-8, calculate VC.

A) 40 V 260°
B) 40 V 2-60°
C) 120 V 2-90°
D) 120 V 290°

Question 48

In a series RLC circuit, R = 1.1 kΩ, XL = 1.6 kΩ, and XC = 2.9 kΩ. ZT = .

A) 4.6 k $\Omega \angle$
-50°
B) 4.6 k $\Omega \angle$
50°
C) 1.7 k $\Omega \angle$
50°
D) 1.7 k $\Omega \angle$
-50°

Question 49

If the bandwidth of a filter increases, .

A) ripples appear in the stopband
B) the roll-off rate increases
C) Q decreases
D) the center frequency decreases

Question 50

calculate VL across the 5Ω inductive reactance

A) 95.0 V 39°
B) 33.9 V 11ec81bf_ec6d_acdc_bc38_29a3f7414e20_TB34225555_11 -58°
C) 95.0 V 11ec81bf_ec6d_acdc_bc38_29a3f7414e20_TB34225555_11 -39°
D) 33.9 V 11ec81bf_ec6d_acdc_bc38_29a3f7414e20_TB34225555_11 58°