Deck 10: Rc Circuits

Question 1

If the operating frequency increases in Figure 10-1, how does the current change?

A)It decreases.
B)It remains the same.
C)It decreases to zero.
D)It increases.

Answer 1

It increases.

Question 2

The phasor combination of V_R and V_C in an R_C series circuit equals the source voltage.

Answer 2

True

Question 3

An RC circuit can be used as a filter to eliminate selected frequencies

Answer 3

True

Question 4

A high pass filter Will cause some phase shifting of the signal.

Question 5

The phasor combination of X_C and R is called Z .

Question 6

If the frequency equals 60 Hz in Figure 10-1 , what is the value of capacitance?

A) 66
B) 22
C) 44
D) 88

Question 7

If the operating frequency increases in Figure 10-1, how does the resistor value change?

A)It increases.
B)It decreases.
C)It opens.
D)It remains the same.

Question 8

A VA rating is more relevant When judging the current delivery capacity for a given signal source.

Question 9

As the frequency applied to an RC circuit increases, the impedance decreases.

Question 10

The phase angle of an RC circuit varies inverselyW ith frequency.

Question 11

The total current in an RC circuit always leads the source Voltage.

Question 12

As the frequency applied to an RC circuit varies, both X_C and resistance vary.

Question 13

The total current in an RC circuit always lags the source Voltage.

Question 14

If the operating frequency increases in Figure 10-1, how does the phase angle change?

A)It remains the name.
B)It increases.
C)It decreases.
D)It changes to another quadrant.

Question 15

What is the circuit's impedance in Figure 10-1?

A) 520
B) 418
C) 280
D) 120

Question 16

When the frequency applied to an RC circuit varies, the value of X_C varies.

Question 17

As the frequency applied to an RC circuit is decreased, the phase angle decreases.

Question 18

What is the true power in Figure 10-1?

A)916 mW
B)5.73W
C)275 mW
D)5.73 mW

Question 19

A leaky capacitor can be equated as a capacitor With a resistor being placed in series With it.

Question 20

Power factor values close to 0 denotes an RC circuit with mostly true power.

Question 21

What is the cutoff frequency in Figure 10-3?

A)995 Hz
B)85 Hz
C)1012 Hz
D)118 Hz

Question 22

The circuit in Figure 10-3 is known as a ________.

A)high-pass filter
B)parallel RC circuit
C)low-pass filter
D)band-pass filter

Question 23

If the operating frequency decreases in Figure 10-1, how does the capacitance value change?

A)It decreases to zero.
B)It decreases.
C)It increases.
D)It remains the same.

Question 24

If the operating frequency decreases in Figure 10-1, how does the resistance value change?

A)It remains the same.
B)It opens.
C)It increases.
D)It decreases.

Question 25

How much voltage does the resistor drop in Figure 10-2?

A)19.94V
B)10V
C)20V
D)59 mV

Question 26

What change would decrease the power factor in Figure 10-2 ?

A) increasing the value of the resistor
B) decreasing the value of the capacitor
C) increasing the value of V_s
D) increasing the value of the capacitor

Question 27

If the frequency decreases in Figure 10-1, the phase angle ________ and the impedance ________.

A)decreases, increases
B)decreases, decreases
C)increases, increases
D)increases, decreases

Question 28

If the frequency increases in Figure 10-1, the phase angle ________ and the impedance ________.

A)decreases, decreases
B)decreases, increases
C)increases, decreases
D)increases, increases

Question 29

Which statement describes the relationship of I_C and I_R in Figure 10-2?

A) I_C leads I_R.
B) They are in phase.
C) I_C lags I_R.
D) They are 180° out of phase.

Question 30

If the resistor changes to 2.2 in Figure 10-1, how does the total current change?

A) It decreases.
B) It remains the same.
C) It decreases to zero.
D) It increases.

Question 31

If the source voltage is changed to 100 V in Figure 10-1, find the true power.

A)22.9 mW
B)3.66W
C)22.9W
D)11W

Question 32

If the operating frequency decreases in Figure 10-1, how does the current change?

A)It increases.
B)It decreases.
C)It decreases to zero.
D)It remains the same.

Question 33

If the operating frequency decreases in Figure 10-1, how does the phase angle change?

A)It changes to another quadrant.
B)It decreases.
C)It increases.
D)It remains the same.

Question 34

Calculate the total impedance in Figure 10-2.

A) 62
B) 880
C) 1000
D) 258

Question 35

If the resistor value increases in Figure 10-2, then how does the total current change?

A)It increases.
B)It decreases.
C)It decreases to zero.
D)It remains the same.

Question 36

Calculate the voltage drop across the capacitor in Figure 10-1.

A)4.82V
B)3.69V
C)14.4V
D)11.5V

Question 37

Calculate the apparent power in Figure 10-1.

A)5.99V
B)1.70V
C)5.66V
D)14.37V

Question 38

How much voltage does the capacitor drop in Figure 10-2?

A)20V
B)19.94V
C)59 mV
D)10V

Question 39

What change Would increase the power factor in Figure 10-2?

A) Increasing the value of the capacitor
B) Increasing the value of the resistor
C) Decreasing the value of the capacitor
D) Increasing the value of the source voltage

Question 40

If the frequency is 400 Hz in Figure 10-1 , what is the value of capacitance?

A) 6.6
B) 10
C) 8.8
D) 3.3

Question 41

Power in an RC circuit can be measured as:

A) true power (P_true).
B) apparent power (P_a) .
C) reactive power (P_r) .
D) all of these.

Question 42

A power factor of 1 indicates that the circuit phase angle is

A) 90°
B) 45°
C) 0°
D) 180°

Question 43

If there is 10 V_RMS across the resistor and 10V_RMS across the capacitor in a series RC circuit, then the source voltage equals

A) 14.1 V_RMS
B) 28.3 V_RMS
C) 20 V_RMS
D) 10 V_RMS

Question 44

If the circuit in Figure 10-3 has an output voltage thatʹs too high at the cutoff frequency, ________.

A)the resistor has opened
B)the resistor has shorted
C)the capacitor has become leaky
D)the capacitor has shorted

Question 45

If the output Were taken across the resistor in Figure 10-3, the circuit Would be known as a ________.

A)low-pass filter
B)high-pass filter
C)band-notch filter
D)band-pass filter

Question 46

If the bandwidth of a low-pass filter is 0 to 1 kHz, the cutoff frequency is ________.

A)500 Hz
B)1 kHz
C)2 kHz
D)0 Hz

Question 47

If the resistance is reduced to 4 in Figure 10-3, the cutoff frequency equals

A) 995 Hz
B) 480 Hz
C) 99 Hz
D) 6250 Hz

Question 48

In an RC filter circuit, the cutoff frequency is defined as the frequency at Which:

A) the output voltage drops to 70% of maximum.
B) the output voltage is cutoff, with minimum or zero output.
C) the output voltage drops to 66% of maximum.
D) the output voltage drops to 33% of maximum.

Question 49

If the resistor is changed to 100 in Figure 10-3 , what is the new cutoff frequency?

A) 159 Hz
B) 79.6 Hz
C) 39.8 Hz
D) 318 Hz

Question 50

If the input voltage increases to 50 V in Figure 10-3,What is the output voltage at the cutoff frequency?

A)70.7V
B)17.7V
C)35.4V
D)8.84V

Question 51

An RC high pass filter takes its output across:

A)the parallel resistor.
B)the parallel capacitor.
C)the series resistor.
D)the series capacitor.

Question 52

If the resistor changes to 2.2 in Figure 10-3 , the new cut off frequency equals

A) 995 Hz
B) 1.18 kHz
C) 1.81 kHz
D) 1.01 kHz

Question 53

If there is 1 A_RMS through the resistor and 1 A_RMS through the capacitor in a parallel RC circuit, then the total current equals

A) 2.28 A_RMS
B) 1.41 A_RMS
C) 1 A_RMS
D) 2 A_RMS

Question 54

When an AC voltage is supplied to an RC circuit, the AC's current and amplitude will be:

A) varying in the same manner.
B) leading the voltage.
C) similar in waveform.
D) all of these.

Question 55

An RC lag network is similar to a:

A)stop pass filter.
B)high pass filter.
C)low pass filter.
D)band pass filter.

Question 56

What is the circuit fault in Figure 10-3 if the output voltage equals 0 V at the cutoff frequency?

A)The capacitor has become leaky.
B)The capacitor has shorted.
C)The capacitor has opened.
D)The resistor has shorted.

Question 57

What is the output voltage at the cutoff frequency in Figure 10-3?

A)15.6V
B)31.1V
C)22V
D)6.45V

Question 58

If the true power is 100 W and the reactive power is 100 VAR , the apparent power is

A) 141 W
B) 200 VA
C) 141 VA
D) 100 VA

Question 59

In an RC circuit, the capacitive reactance is:

A) decreases as the frequency increases.
B) inversely proportional to the frequency.
C) inversely proportional to the capacitance.
D) all of these.

Question 60

In a series RC circuit, as the phase angle between the applied voltage and the total current increases, this is the same as:

A)apparent power decreasing.
B)power factor increasing.
C)power factor decreasing.
D)true power decreasing.

Question 61

Simple RC circuits can be viewed asW hat type of filter?

A)active
B)high pass
C)passive
D)low pass

Question 62

This frequency response curve in Figure 10-4 representsW hat type of filter?

A)band pass
B)band stop
C)low pass
D)high pass

Question 63

Which of these troubleshooting procedures should be performed first?

A)Slap the device firmly to dislodge foreign objects.
B)Take random measurements around point of failure.
C)Analyze the problem and decide Where best to start.
D)Check test equipment connections.

Question 64

It has been determined that the phase shift of a given parallel RC circuit is lower than predicted. Which of the following most likely has caused this?

A)Resistance has decreased.
B)The function generator frequency control has been accidentally moved to a lower frequency.
C)The capacitance has decreased.
D)could be A or C

Question 65

The output voltage of an RC high pass filter at a designated frequency is low.What is a possible problem?

A)not enough information
B)function generator misadjusted
C)open resistor
D)shorted capacitor