Deck 8: Circuit Theorems and Conversions

Question 1

which of the following can be measured from points B to F in Figure ?

A)the peak-to-peak voltage
B)the frequency
C)the period
D)the angle

Answer 1

the period

Question 2

A sine waveʹs peak value is smaller than its RMS value.

Answer 2

False

Question 3

Commercial line voltages are usually square waves at a frequency of 60 Hz.

Answer 3

False

Question 4

Kirchhoffʹs voltage law can be used with resistive ac circuits.

Question 5

The RMS value of a sine wave means ________.

A)the root mean square value
B)the heating effect of an ac generator of the same voltage
C)the same as IPP × R
D)the same as IP × R

Question 6

20 Vrms of alternating current will illuminate a given lamp at the same intensity as 20 V of direct
current.

Question 7

Which point in Figure is 180° away from point E?

A)A
B)B
C)C
D)D

Question 8

Rise time, fall time, and duty cycle are all terms associated with sine wave measurement.

Question 9

A sine waveʹs frequency equals the reciprocal of its period.

Question 10

The higher a sine waveʹs frequency, the shorter its period.

Question 11

VPP is measured between points ________ in Figure.

A)A and B
B)D and F
C)G and I
D)C and H

Question 12

One complete sine wave contains 360°.

Question 13

The term RMS stands for ʺroot-mean-square.ʺ

Question 14

An ac current is inversely proportional to an ac voltage.

Question 15

The period of a 5 Hz wave form is 200 ms.

Question 16

What is the instantaneous voltage at 42° on a 230 VP sine wave?

A)154 V
B)115 V
C)149 V
D)76.1 V

Question 17

Only frequency increases with the speed of an AC generator.

Question 18

Which one of the following represents the value at point G in Figure 8-1?

A)the period
B)the peak voltage
C)the frequency
D)the RMS voltage

Question 19

Current flows both ways simultaneously in an AC circuit.

Question 20

RMS is another name for peak.

Question 21

If R shorts in Figure 8-2, V ________.

A)decreases
B)remains the same
C)increases

Question 22

In Figure , the time from point C to E is called ________.

A)a cycle
B)the period
C)peak voltage
D)a half-cycle

Question 23

If you measure about 56 VPP across the source in Figure 8-2, what is the trouble?

A) is open.
B) are open.
C) is open.
D)There is no trouble. 56 VPP is a normal measurement for the source voltage.
E)any of these

Question 24

If a rectangular waveʹs pulse width is and its frequency is 4 kHz, its duty cycle is ________.

A)98.75%
B)20%
C)1.25%
D)80%

Question 25

In Figure 8-2, what is the instantaneous voltage across at an angle of 22°?

A)8.03 V
B)2.56 V
C)20.3 V
D)12.0 V

Question 26

What is the approximate peak input voltage to the circuit in Figure 8-2?

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

Question 27

Calculate the total power dissipation in the circuit in Figure 8-2.

A)182 mW
B)64.5 mW
C)9.12 mW
D)45.6 mW

Question 28

Calculate in Figure .

A)6.84 VPP
B)6.84 VP
C)13.15 VP
D)4.84 VP

Question 29

opens in Figure 8-2.

A)decreases
B)remains the same
C)increases

Question 30

In Figure 8-1, if the time from point A to H is 60 μs the frequency is ________.

A)16.7 kHz
B)25 kHz
C)50 kHz
D)More information is required to calculate the frequency.

Question 31

Calculate in Figure 8-2.

A)9.12 mAPP
B)3.22 mAPP
C)6.44 mAPP
D)4.55 mAPP

Question 32

What is the instantaneous voltage at on a 22 VPP sine wave?

A)10.7 V
B)0.33 V
C)-2.66 V
D)-10.7 V

Question 33

What is the approximate instantaneous voltage at 37° on a 169 VP sine wave?

A)239 V
B)135 V
C)102 V
D)119 V

Question 34

In Figure 8-2, if you look at VR1 with an oscilloscope and you find no trace, a possible trouble might be that ________.

A) is shorted
B) is open
C) is open
D) has changed

Question 35

In Figure 8-2, what is the instantaneous voltage across

A)11.2 V
B)11.6 V
C)5.8 V
D)18.2 V

Question 36

The time required by a 10 V square wave to change from 1 V to 9 V is known as the ________.

A)fall time
B)pulse width
C)period
D)rise time

Question 37

In Figure , which of the following can be measured from point E to point F?

A)the peak to peak voltage
B)the peak voltage
C)the RMS voltage
D)one cycle of voltage

Question 38

Calculate in Figure 8-2.

A)6.84 VP
B)13.2 VP
C)13.7 VP
D)21.4 VP

Question 39

Find in Figure 8-2.

A)0 W
B)196 mW
C)48.9 mW
D)97.8 mW

Question 40

Find in Figure 8-2.

A)
B)
C)
D)

Question 41

A 60 Hz sine wave completes ________ cycles every 10 seconds.

A)600
B)1/16
C)10
D)6

Question 42

What is the instantaneous voltage at

A)49.4 V
B)80.5 V
C)161 V
D)98.8 V

Question 43

An oscilloscopeʹs seconds/division switch is set on 20 ms/div. horizontally, what frequency is being measured?

A)12.5 Hz
B)25 Hz
C)50 Hz
D)More information is needed.

Question 44

A sine waveʹs instantaneous voltage is 0 V at ________ degrees.

A)360
B)0
C)180
D)all of these

Question 45

The formula to convert degrees to radians is:

A)
B)
C)
D)all of these.

Question 46

The time (T) and the frequency (f) of an AC waveform are related as:

A)universally proportional.
B)directly proportional.
C)inversely proportional.
D)complimentary proportional.

Question 47

In a two-resistor series circuit VR1 = 6.5 VRMS and VR2 = 3.2 VRMS. ________.

A)9.19 VP
B)4.53 VP
C)9.7 VP
D)13.7 VP

Question 48

The average value of a rectangular pulse wave is calculated as:

A)Vavg = 0.637 Vp.
B)Vavg = Vbaseline + (duty cycle)× Vp.
C)Vavg = 1.57 Vp.
D)Vavg = Vbaseline + Vp.

Question 49

If a resistor carries 5 mARMS of current, its voltage drop equals ________.

A)5 VRMS
B)50 VRMS
C)7.07 VRMS
D)70.7 VRMS

Question 50

The period of most AC waveforms is measured in units of:

A)alternations.
B)seconds.
C)cycles.
D)revolutions.

Question 51

An oscilloscopeʹs volts/division switch is set on 50 mV/div. oscilloscopeʹs trace is 1.6 division, what voltage is being measured?

A)0.008 V
B)50 mV
C)1.6 mV
D)80 mV

Question 52

A square wave is a unique form of the rectangular pulse wave in that:

A)the duty cycle is 50%.
B)the positive and negative halves are equal.
C)the wave is symmetrical.
D)all of these

Question 53

The symbol for the period of a wave form is:

A)W.
B)T.
C)P.
D)F.

Question 54

Superimposed DC and AC voltages mean the two voltages are combined:

A)in series-parallel aiding or opposing.
B)in parallel aiding or opposing.
C)in series aiding or opposing.
D)all of these

Question 55

The AC sine wave varies from zero to its maximum value in accordance with:

A)a trigonometric relationship.
B)a geometric progression.
C)an algebraic function.
D)a mathematical formula.

Question 56

A 12 VP sine wave equals ________.

A)8.48 VRMS
B)7.64 VAVG
C)24 VPP
D)all of these

Question 57

A formula for VRMS is ________.

A)2 × VP
B)2.8 × VP
C)0.707 × VP
D)0.707 × VPP

Question 58

A 10 VP sine wave is equal to ________.

A)20 VPP
B)100 VPP
C)5 VPP
D)none of the above

Question 59

An oscilloscopeʹs seconds/division switch is set on . period?

A)
B)
C)
D)0.0015 s

Question 60

If the period of a square wave is 22 ms, what is its frequency?

A)45.5 kHz
B)45.5 Hz
C)22 kHz
D)22 Hz

Question 61

While troubleshooting a circuit the voltage seems to be zero; what if any adjustment should be checked on the oscilloscope?

A)trigger level
B)AC/GND/DC switch
C)focus setting
D)time division setting

Question 62

The square wave is made up of:

A)just the fundamental frequency.
B)the fundamental frequency and both the odd and even harmonics.
C)the fundamental frequency and all the even harmonics.
D)the fundamental frequency and all the odd harmonics.

Question 63

Superimposing an AC voltage of 3.54 Vrms with a DC source of 10 V results in a waveform that:

A)peaks at 15 V.
B)peaks at 13.54 V.
C)peaks at 20 V.
D)both B and C

Question 64

Troubleshooting an AC circuit can be performed with which of the following tools?

A)digital multimeter
B)analog voltmeter
C)oscilloscope
D)any of the above

Question 65

This display in Figure 8-3 illustrates maladjustment of which control on the oscilloscope?

A)coupling
B)trigger level
C)intensity
D)volts/div

Question 66

The largest numerical value in the measurement of alternating current is:

A)peak to peak.
B)rms.
C)average.
D)peak.

Question 67

The value of a AC sine wave at any instant can be represented by:

A)a phasor whose angle and magnitude are representative of the AC signal.
B)
C)a graph of the voltage or current vs. the angular measurement.
D)all of these.