electrical principles 1 g5 - electrical principles [3 exam questions - 3 groups] g5aresistance;...
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Electrical Principles1
G5 - ELECTRICAL PRINCIPLES G5 - ELECTRICAL PRINCIPLES [3 exam questions - 3 groups] [3 exam questions - 3 groups]
G5AG5A Resistance; reactance; inductance; capacitance; Resistance; reactance; inductance; capacitance; impedance; impedance matching impedance; impedance matching
G5BG5B The Decibel; current and voltage dividers; The Decibel; current and voltage dividers; electrical power calculations; sine wave root-electrical power calculations; sine wave root-mean-square (RMS) values; PEP calculationsmean-square (RMS) values; PEP calculations
G5CG5C Resistors, capacitors, and inductors in series and Resistors, capacitors, and inductors in series and parallel; transformers parallel; transformers
Resistance, Impedance and ReactanceResistance, Impedance and Reactance
RESISTANCERESISTANCE IS THE OPPOSITION TO THE FLOW OF DIRECT IS THE OPPOSITION TO THE FLOW OF DIRECT CURRENT (DC). REPRESENTED AS THE LETTER RCURRENT (DC). REPRESENTED AS THE LETTER R
REACTANCEREACTANCE IS THE OPPOSITION TO THE FLOW OF IS THE OPPOSITION TO THE FLOW OF ALTERNATING CURRENT (AC) THAT A CAPACITOR OR ALTERNATING CURRENT (AC) THAT A CAPACITOR OR INDUCTOR PRESENTS. REPRESENTED AS THE LETTER ZINDUCTOR PRESENTS. REPRESENTED AS THE LETTER Z
IMPEDANCEIMPEDANCE IS THE OPPOSITION TO THE FLOW OF IS THE OPPOSITION TO THE FLOW OF ALTERNAING CURRENT (AC) AND VARIES AS FREQUENCY ALTERNAING CURRENT (AC) AND VARIES AS FREQUENCY VARIES AND MAY INCLUDE XVARIES AND MAY INCLUDE XL L , X, XCC AND R COMPONENTS. AND R COMPONENTS.
Electrical Principles2
Electrical Principles3
G5A01 What is impedance?G5A01 What is impedance?
A.A. The electric charge stored by a capacitorThe electric charge stored by a capacitor
B.B. The inverse of resistanceThe inverse of resistance
C.C. The opposition to the flow of current in an AC circuitThe opposition to the flow of current in an AC circuit
D.D. The force of repulsion between two similar electric The force of repulsion between two similar electric fieldsfields
Electrical Principles4
G5A01 What is impedance?G5A01 What is impedance?
A.A. The electric charge stored by a capacitorThe electric charge stored by a capacitor
B.B. The inverse of resistanceThe inverse of resistance
C.C. The opposition to the flow of current in an The opposition to the flow of current in an AC circuitAC circuit
D.D. The force of repulsion between two similar electric The force of repulsion between two similar electric fieldsfields
Electrical Principles6
G5A02 What is reactance?G5A02 What is reactance?
A.A. Opposition to the flow of direct current caused by Opposition to the flow of direct current caused by resistanceresistance
B.B. Opposition to the flow of alternating current caused Opposition to the flow of alternating current caused by capacitance or inductanceby capacitance or inductance
C.C. A property of ideal resistors in AC circuitsA property of ideal resistors in AC circuits
D.D. A large spark produced at switch contacts when an A large spark produced at switch contacts when an inductor is de-energizedinductor is de-energized
Electrical Principles7
G5A02 What is reactance?G5A02 What is reactance?
A.A. Opposition to the flow of direct current caused by Opposition to the flow of direct current caused by resistanceresistance
B.B. Opposition to the flow of alternating Opposition to the flow of alternating current caused by capacitance or inductancecurrent caused by capacitance or inductance
C.C. A property of ideal resistors in AC circuitsA property of ideal resistors in AC circuits
D.D. A large spark produced at switch contacts when an A large spark produced at switch contacts when an inductor is de-energizedinductor is de-energized
Electrical Principles8
G5A03 Which of the following causes G5A03 Which of the following causes opposition to the flow of alternating opposition to the flow of alternating current in an inductor?current in an inductor?
A.A. ConductanceConductance
B.B. ReluctanceReluctance
C.C. AdmittanceAdmittance
D.D. ReactanceReactance
Electrical Principles9
G5A03 Which of the following causes G5A03 Which of the following causes opposition to the flow of alternating opposition to the flow of alternating current in an inductor?current in an inductor?
A.A. ConductanceConductance
B.B. ReluctanceReluctance
C.C. AdmittanceAdmittance
D.D. ReactanceReactance
Inductor is also called a Coil Inductor is also called a Coil
Electrical Principles10
G5A04 Which of the following causes G5A04 Which of the following causes opposition to the flow of alternating opposition to the flow of alternating current in a capacitor?current in a capacitor?
A.A. ConductanceConductance
B.B. ReluctanceReluctance
C.C. ReactanceReactance
D.D. AdmittanceAdmittance
Electrical Principles11
G5A04 Which of the following causes G5A04 Which of the following causes opposition to the flow of alternating opposition to the flow of alternating current in a capacitor?current in a capacitor?
A.A. ConductanceConductance
B.B. ReluctanceReluctance
C.C. ReactanceReactanceD.D. AdmittanceAdmittance
Electrical Principles12
G5A05 How does a coil react to AC?G5A05 How does a coil react to AC?
A.A. As the frequency of the applied AC increases, the As the frequency of the applied AC increases, the reactance decreasesreactance decreases
B.B. As the amplitude of the applied AC increases, the As the amplitude of the applied AC increases, the reactance increasesreactance increases
C.C. As the amplitude of the applied AC increases, the As the amplitude of the applied AC increases, the reactance decreasesreactance decreases
D.D. As the frequency of the applied AC increases, the As the frequency of the applied AC increases, the reactance increasesreactance increases
Electrical Principles13
G5A05 How does a coil react to AC?G5A05 How does a coil react to AC?
D.D. As the frequency of the applied AC As the frequency of the applied AC increases, the reactance increasesincreases, the reactance increases
Electrical Principles14
G5A06 How does a capacitor react to G5A06 How does a capacitor react to AC?AC?
A.A. As the frequency of the applied AC increases, the As the frequency of the applied AC increases, the reactance decreasesreactance decreases
B.B. As the frequency of the applied AC increases, the As the frequency of the applied AC increases, the reactance increasesreactance increases
C.C. As the amplitude of the applied AC increases, the As the amplitude of the applied AC increases, the reactance increasesreactance increases
D.D. As the amplitude of the applied AC increases, the As the amplitude of the applied AC increases, the reactance decreasesreactance decreases
Electrical Principles15
G5A06 How does a capacitor react to G5A06 How does a capacitor react to AC?AC?
A.A. As the frequency of the applied AC As the frequency of the applied AC increases, the reactance decreasesincreases, the reactance decreases
Electrical Principles16
G5A07 What happens when the G5A07 What happens when the impedance of an electrical load is equal impedance of an electrical load is equal to the internal impedance of the power to the internal impedance of the power source?source?
A.A. The source delivers minimum power to the loadThe source delivers minimum power to the load
B.B. The electrical load is shortedThe electrical load is shorted
C.C. No current can flow through the circuitNo current can flow through the circuit
D.D. The source can deliver maximum power to the loadThe source can deliver maximum power to the load
Electrical Principles17
G5A07 What happens when the G5A07 What happens when the impedance of an electrical load is equal impedance of an electrical load is equal to the internal impedance of the power to the internal impedance of the power source?source?
A.A. The source delivers minimum power to the loadThe source delivers minimum power to the load
B.B. The electrical load is shortedThe electrical load is shorted
C.C. No current can flow through the circuitNo current can flow through the circuit
D.D. The source can deliver maximum power to The source can deliver maximum power to the loadthe load
Electrical Principles18
G5A08 Why is impedance matching G5A08 Why is impedance matching important?important?
A.A. So the source can deliver maximum power to the So the source can deliver maximum power to the loadload
B.B. So the load will draw minimum power from the So the load will draw minimum power from the sourcesource
C.C. To ensure that there is less resistance than To ensure that there is less resistance than reactance in the circuitreactance in the circuit
D.D. To ensure that the resistance and reactance in the To ensure that the resistance and reactance in the circuit are equalcircuit are equal
Electrical Principles19
G5A08 Why is impedance matching G5A08 Why is impedance matching important?important?
A.A. So the source can deliver maximum power So the source can deliver maximum power to the loadto the load
B.B. So the load will draw minimum power from the So the load will draw minimum power from the sourcesource
C.C. To ensure that there is less resistance than To ensure that there is less resistance than reactance in the circuitreactance in the circuit
D.D. To ensure that the resistance and reactance in the To ensure that the resistance and reactance in the circuit are equalcircuit are equal
Electrical Principles20
G5A09 What unit is used to measure G5A09 What unit is used to measure reactance?reactance?
A.A. FaradFarad
B.B. OhmOhm
C.C. AmpereAmpere
D.D. SiemensSiemens
Electrical Principles21
G5A09 What unit is used to measure G5A09 What unit is used to measure reactance?reactance?
A.A. FaradFarad
B.B. Ohm Ohm C.C. AmpereAmpere
D.D. SiemensSiemens
Ohm is also used to measure resistance.Ohm is also used to measure resistance.
Electrical Principles22
G5A10 What unit is used to measure G5A10 What unit is used to measure impedance?impedance?
A.A. VoltVolt
B.B. OhmOhm
C.C. AmpereAmpere
D.D. WattWatt
Electrical Principles23
G5A10 What unit is used to measure G5A10 What unit is used to measure impedance?impedance?
A.A. VoltVolt
B.B. OhmOhmC.C. AmpereAmpere
D.D. WattWatt
Same unit of measurement for Reactance, Same unit of measurement for Reactance, Resistance, Impedance.Resistance, Impedance.
Electrical Principles24
G5A11 Why should core saturation of a G5A11 Why should core saturation of a conventional impedance matching conventional impedance matching transformer be avoided?transformer be avoided?
A.A. Harmonics and distortion could resultHarmonics and distortion could result
B.B. Magnetic flux would increase with frequencyMagnetic flux would increase with frequency
C.C. RF susceptance would increaseRF susceptance would increase
D.D. Temporary changes of the core permeability could Temporary changes of the core permeability could resultresult
Electrical Principles25
G5A11 Why should core saturation of a G5A11 Why should core saturation of a conventional impedance matching conventional impedance matching transformer be avoided?transformer be avoided?
A.A. Harmonics and distortion could resultHarmonics and distortion could result
B.B. Magnetic flux would increase with frequencyMagnetic flux would increase with frequency
C.C. RF susceptance would increaseRF susceptance would increase
D.D. Temporary changes of the core permeability could resultTemporary changes of the core permeability could result
Electrical Principles26
G5A12 What is one reason to use an G5A12 What is one reason to use an impedance matching transformer?impedance matching transformer?
A.A. To reduce power dissipation in the transmitterTo reduce power dissipation in the transmitter
B.B. To maximize the transfer of powerTo maximize the transfer of power
C.C. To minimize SWR at the antennaTo minimize SWR at the antenna
D.D. To minimize SWR in the transmission lineTo minimize SWR in the transmission line
Electrical Principles27
G5A12 What is one reason to use an G5A12 What is one reason to use an impedance matching transformer?impedance matching transformer?
A.A. To reduce power dissipation in the transmitterTo reduce power dissipation in the transmitter
B.B. To maximize the transfer of powerTo maximize the transfer of powerC.C. To minimize SWR at the antennaTo minimize SWR at the antenna
D.D. To minimize SWR in the transmission lineTo minimize SWR in the transmission line
Electrical Principles29
G5A13 Which of the following devices G5A13 Which of the following devices can be used for impedance matching at can be used for impedance matching at radio frequencies?radio frequencies?
A.A. A transformerA transformer
B.B. A Pi-networkA Pi-network
C.C. A length of transmission lineA length of transmission line
D.D. All of these choices are correctAll of these choices are correct
Electrical Principles30
G5A13 Which of the following devices G5A13 Which of the following devices can be used for impedance matching at can be used for impedance matching at radio frequencies?radio frequencies?
A.A. A transformerA transformer
B.B. A Pi-networkA Pi-network
C.C. A length of transmission lineA length of transmission line
D.D. All of these choices are correctAll of these choices are correct
Electrical Principles31
G5A14 Which of the following describes G5A14 Which of the following describes one method of impedance matching one method of impedance matching between two AC circuits?between two AC circuits?
A.A. Insert an LC network between the two circuitsInsert an LC network between the two circuits
B.B. Reduce the power output of the first circuitReduce the power output of the first circuit
C.C. Increase the power output of the first circuitIncrease the power output of the first circuit
D.D. Insert a circulator between the two circuitsInsert a circulator between the two circuits
Electrical Principles32
G5A14 Which of the following describes G5A14 Which of the following describes one method of impedance matching one method of impedance matching between two AC circuits?between two AC circuits?
A.A. Insert an LC network between the two Insert an LC network between the two circuitscircuits
B.B. Reduce the power output of the first circuitReduce the power output of the first circuit
C.C. Increase the power output of the first circuitIncrease the power output of the first circuit
D.D. Insert a circulator between the two circuitsInsert a circulator between the two circuits
Amateur Radio Practices33
Decibel MultipliersDecibel Multipliers
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The Decibel scale is logarithmic. 3dB represents a 2-fold increase in power, 6dB is 4 fold, 10dB is 10-fold, 20dB is 100-fold. The S-Unit scale on a receiver meter is not an absolute scale and can vary from radio to radio. Although these meters are not calibrated, they can be useful for verifying antenna performance. One “S-Unit” represents a 4-fold change in power or 6dB.
Electrical Principles34
G5B01 A two-times increase or G5B01 A two-times increase or decrease in power results in a change decrease in power results in a change of how many dB?of how many dB?
A.A. 2 dB2 dB
B.B. 3 dB3 dB
C.C. 6 dB6 dB
D.D. 12 dB12 dB
Electrical Principles35
G5B01 A two-times increase or G5B01 A two-times increase or decrease in power results in a change decrease in power results in a change of how many dB?of how many dB?
A.A. 2 dB2 dB
B.B. 3 dB3 dBC.C. 6 dB6 dB
D.D. 12 dB12 dB
Pm Pm db=10log db=10log1010 ------ ------ Pref Pref
Pm = Measured Power, Pref = Reference PowerPm = Measured Power, Pref = Reference Power
Electrical Principles36
G5B02 How does the total current G5B02 How does the total current relate to the individual currents in each relate to the individual currents in each branch of a parallel circuit?branch of a parallel circuit?
A.A. It equals the average of each branch currentIt equals the average of each branch current
B.B. It decreases as more parallel branches are added to It decreases as more parallel branches are added to the circuitthe circuit
C.C. It equals the sum of the currents through each It equals the sum of the currents through each branchbranch
D.D. It is the sum of the reciprocal of each individual It is the sum of the reciprocal of each individual voltage dropvoltage drop
Electrical Principles37
G5B02 How does the total current G5B02 How does the total current relate to the individual currents in each relate to the individual currents in each branch of a parallel circuit?branch of a parallel circuit?
A.A. It equals the average of each branch currentIt equals the average of each branch current
B.B. It decreases as more parallel branches are added to It decreases as more parallel branches are added to the circuitthe circuit
C.C. It equals the sum of the currents through It equals the sum of the currents through each brancheach branch
D.D. It is the sum of the reciprocal of each individual It is the sum of the reciprocal of each individual voltage dropvoltage drop
Electrical Principles38
Ohm’s Law and Power CalculationsOhm’s Law and Power Calculations
E
I R
P
I EE=Voltage (Volts)
I=Current (Amps)
R=Resistance (Ohms)
P=Power (Watts)
E = I * R P = I * E
Electrical Principles39
G5B03 How many watts of electrical G5B03 How many watts of electrical power are used if 400 VDC is supplied power are used if 400 VDC is supplied to an 800-ohm load?to an 800-ohm load?
A.A. 0.5 watts0.5 watts
B.B. 200 watts200 watts
C.C. 400 watts400 watts
D.D. 3200 watts3200 watts
Electrical Principles40
G5B03 How many watts of electrical G5B03 How many watts of electrical power are used if 400 VDC is supplied power are used if 400 VDC is supplied to an 800-ohm load?to an 800-ohm load?
A.A. 0.5 watts0.5 watts
B.B. 200 watts200 wattsC.C. 400 watts400 watts
D.D. 3200 watts3200 watts
P = E P = E22 / R / R P = 160,000 / 800 P = 160,000 / 800 P = 200 watts P = 200 watts
E
I R
Electrical Principles41
G5B04 How many watts of electrical G5B04 How many watts of electrical power are used by a 12-VDC light bulb power are used by a 12-VDC light bulb that draws 0.2 amperes?that draws 0.2 amperes?
A.A. 2.4 watts2.4 watts
B.B. 24 watts24 watts
C.C. 6 watts6 watts
D.D. 60 watts60 watts
P
I E
Electrical Principles42
G5B04 How many watts of electrical G5B04 How many watts of electrical power are used by a 12-VDC light bulb power are used by a 12-VDC light bulb that draws 0.2 amperes?that draws 0.2 amperes?
A.A. 2.4 watts2.4 wattsB.B. 24 watts24 watts
C.C. 6 watts6 watts
D.D. 60 watts60 watts
P = I * E P = I * E P = .2 * 12 P = .2 * 12 P = 2.4 watts P = 2.4 watts
P
I E
Electrical Principles43
G5B05 How many watts are being G5B05 How many watts are being dissipated when a current of 7.0 dissipated when a current of 7.0 milliamperes flows through 1.25 milliamperes flows through 1.25 kilohms?kilohms?
A.A. Approximately 61 milliwattsApproximately 61 milliwatts
B.B. Approximately 39 milliwattsApproximately 39 milliwatts
C.C. Approximately 11 milliwattsApproximately 11 milliwatts
D.D. Approximately 9 milliwattsApproximately 9 milliwatts
Electrical Principles44
G5B05 How many watts are being G5B05 How many watts are being dissipated when a current of 7.0 dissipated when a current of 7.0 milliamperes flows through 1.25 milliamperes flows through 1.25 kilohms?kilohms?
A.A. Approximately 61 milliwattsApproximately 61 milliwattsB.B. Approximately 39 milliwattsApproximately 39 milliwatts
C.C. Approximately 11 milliwattsApproximately 11 milliwatts
D.D. Approximately 9 milliwattsApproximately 9 milliwatts
P=I * I * R P=I * I * R P= I P= I22 * R * R P = .007*.007 * 1250 P = .007*.007 * 1250 P= .06125 = 61 milliwatts P= .06125 = 61 milliwatts
E
I R
Electrical Principles45
RMS, Peak and Peak to Peak VoltagesRMS, Peak and Peak to Peak Voltages
There are three key voltage measurements, RMS (Vrms), Peak (Vpk) and Peak to Peak (Vpp).
Electrical Principles46
RMS, Peak and Peak to Peak VoltagesRMS, Peak and Peak to Peak Voltages
The Peak voltage is relative to ground.
Electrical Principles47
RMS, Peak and Peak to Peak VoltagesRMS, Peak and Peak to Peak Voltages
RMS or Root Mean Square is more of an “average” voltage over the duration of the AC cycle. RMS voltage is calculated by multiplying 0.707 times the peak voltage.
Electrical Principles48
RMS, Peak and Peak to Peak VoltagesRMS, Peak and Peak to Peak Voltages
The Peak to Peak voltage measures from the peak of the positive swing to the peak of the negative swing.
PEPPEPPeak envelope power is the average Peak envelope power is the average power supplied supplied
to the to the antenna transmission line by a by a transmitter during one during one radio frequency cycle at the crest of cycle at the crest of the the modulation envelope, under normal operating , under normal operating conditions.conditions.
PEP was often used in non-PEP was often used in non-broadcast amplitude modulation (AM) applications because it (AM) applications because it most accurately described the potential of mobile most accurately described the potential of mobile transmitters to interfere with each other. Its use is transmitters to interfere with each other. Its use is now somewhat now somewhat deprecated, with the , with the averageaverage transmitter power output (or sometimes (or sometimes effective radiated power) now typically being ) now typically being preferred.preferred.
Electrical Principles49
Electrical Principles50
G5B06 What is the output PEP from a G5B06 What is the output PEP from a transmitter if an oscilloscope measures transmitter if an oscilloscope measures 200 volts peak-to-peak across a 50-ohm 200 volts peak-to-peak across a 50-ohm dummy load connected to the dummy load connected to the transmitter output?transmitter output?
A.A. 1.4 watts1.4 watts
B.B. 100 watts100 watts
C.C. 353.5 watts353.5 watts
D.D. 400 watts400 watts
Electrical Principles51
G5B06 What is the output PEP from a G5B06 What is the output PEP from a transmitter if an oscilloscope measures transmitter if an oscilloscope measures 200 volts peak-to-peak across a 50-ohm 200 volts peak-to-peak across a 50-ohm dummy load connected to the dummy load connected to the transmitter output?transmitter output?
A.A. 1.4 watts1.4 watts
B.B. 100 watts100 wattsC.C. 353.5 watts353.5 watts
D.D. 400 watts400 watts
PEP = ((V PEP = ((Vpppp/2)*.707)/2)*.707)22
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RRLoadLoad
Electrical Principles52
G5B07 Which measurement of an AC G5B07 Which measurement of an AC signal is equivalent to a DC voltage of signal is equivalent to a DC voltage of the same value?the same value?
A.A. The peak-to-peak valueThe peak-to-peak value
B.B. The peak valueThe peak value
C.C. The RMS valueThe RMS value
D.D. The reciprocal of the RMS valueThe reciprocal of the RMS value
Electrical Principles53
G5B07 Which measurement of an AC G5B07 Which measurement of an AC signal is equivalent to a DC voltage of signal is equivalent to a DC voltage of the same value?the same value?
A.A. The peak-to-peak valueThe peak-to-peak value
B.B. The peak valueThe peak value
C.C. The RMS valueThe RMS valueD.D. The reciprocal of the RMS valueThe reciprocal of the RMS value
Electrical Principles54
G5B08 What is the peak-to-peak G5B08 What is the peak-to-peak voltage of a sine wave that has an RMS voltage of a sine wave that has an RMS voltage of 120 volts?voltage of 120 volts?
A.A. 84.8 volts84.8 volts
B.B. 169.7 volts169.7 volts
C.C. 240.0 volts240.0 volts
D.D. 339.4 volts339.4 volts
Electrical Principles55
G5B08 What is the peak-to-peak G5B08 What is the peak-to-peak voltage of a sine wave that has an RMS voltage of a sine wave that has an RMS voltage of 120 volts?voltage of 120 volts?
A.A. 84.8 volts84.8 volts
B.B. 169.7 volts169.7 volts
C.C. 240.0 volts240.0 volts
D.D. 339.4 volts339.4 volts
Peak Voltage = RMS *1/.707Peak Voltage = RMS * 1.414Peak Voltage = 169.68Peak to Peak = 169.68 * 2Peak to Peak = 339.4
Electrical Principles56
G5B08 What is the peak-to-peak G5B08 What is the peak-to-peak voltage of a sine wave that has an RMS voltage of a sine wave that has an RMS voltage of 120 volts?voltage of 120 volts?
A.A. 84.8 volts84.8 volts
B.B. 169.7 volts169.7 volts
C.C. 240.0 volts240.0 volts
D.D. 339.4 volts339.4 volts
Peak Voltage = RMS *1/.707Peak Voltage = RMS * 1.414Peak Voltage = 169.68Peak to Peak = 169.68 * 2Peak to Peak = 339.4
Electrical Principles57
G5B08 What is the peak-to-peak G5B08 What is the peak-to-peak voltage of a sine wave that has an RMS voltage of a sine wave that has an RMS voltage of 120 volts?voltage of 120 volts?
A.A. 84.8 volts84.8 volts
B.B. 169.7 volts169.7 volts
C.C. 240.0 volts240.0 volts
D.D. 339.4 volts339.4 volts
Electrical Principles58
G5B09 What is the RMS voltage of sine G5B09 What is the RMS voltage of sine wave with a value of 17 volts peak?wave with a value of 17 volts peak?
A.A. 8.5 volts8.5 volts
B.B. 12 volts12 volts
C.C. 24 volts24 volts
D.D. 34 volts34 volts
Electrical Principles59
G5B09 What is the RMS voltage of sine G5B09 What is the RMS voltage of sine wave with a value of 17 volts peak?wave with a value of 17 volts peak?
A.A. 8.5 volts8.5 volts
B.B. 12 volts12 voltsC.C. 24 volts24 volts
D.D. 34 volts34 volts
Electrical Principles60
G5B11 What is the ratio of peak G5B11 What is the ratio of peak envelope power to average power for envelope power to average power for an unmodulated carrier?an unmodulated carrier?
A.A. .707.707
B.B. 1.001.00
C.C. 1.4141.414
D.D. 2.002.00
Electrical Principles61
G5B11 What is the ratio of peak G5B11 What is the ratio of peak envelope power to average power for envelope power to average power for an unmodulated carrier?an unmodulated carrier?
A.A. .707.707
B.B. 1.001.00C.C. 1.4141.414
D.D. 2.002.00
Electrical Principles62
G5B12 What would be the voltage G5B12 What would be the voltage across a 50-ohm dummy load across a 50-ohm dummy load dissipating 1200 watts?dissipating 1200 watts?
A.A. 173 volts173 volts
B.B. 245 volts245 volts
C.C. 346 volts346 volts
D.D. 692 volts692 volts
Electrical Principles63
G5B12 What would be the voltage G5B12 What would be the voltage across a 50-ohm dummy load across a 50-ohm dummy load dissipating 1200 watts?dissipating 1200 watts?
A.A. 173 volts173 volts
B.B. 245 volts245 voltsC.C. 346 volts346 volts
D.D. 692 volts692 volts
E E rms rms = PEP *R = PEP *R
Electrical Principles64
G5B13 What percentage of power loss G5B13 What percentage of power loss would result from a transmission line would result from a transmission line loss of 1 dB?loss of 1 dB?
A.A. 10.9 %10.9 %
B.B. 12.2 %12.2 %
C.C. 20.5 %20.5 %
D.D. 25.9 %25.9 %
Electrical Principles65
G5B13 What percentage of power loss G5B13 What percentage of power loss would result from a transmission line would result from a transmission line loss of 1 dB?loss of 1 dB?
A.A. 10.9 %10.9 %
B.B. 12.2 %12.2 %
C.C. 20.5 %20.5 %D.D. 25.9 %25.9 %
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Electrical Principles66
G5B14 What is the output PEP from a G5B14 What is the output PEP from a transmitter if an oscilloscope measures transmitter if an oscilloscope measures 500 volts peak-to-peak across a 50-ohm 500 volts peak-to-peak across a 50-ohm resistor connected to the transmitter resistor connected to the transmitter output?output?
A.A. 8.75 watts8.75 watts
B.B. 625 watts625 watts
C.C. 2500 watts2500 watts
D.D. 5000 watts5000 watts
Electrical Principles67
G5B14 What is the output PEP from a G5B14 What is the output PEP from a transmitter if an oscilloscope measures transmitter if an oscilloscope measures 500 volts peak-to-peak across a 50-ohm 500 volts peak-to-peak across a 50-ohm resistor connected to the transmitter resistor connected to the transmitter output?output?
A.A. 8.75 watts8.75 watts
B.B. 625 watts625 wattsC.C. 2500 watts2500 watts
D.D. 5000 watts5000 watts
PEP = ((Vpp/2)*.707)2
------------------- RLoad
Electrical Principles68
G5B15 What is the output PEP of an G5B15 What is the output PEP of an unmodulated carrier if an average unmodulated carrier if an average reading wattmeter connected to the reading wattmeter connected to the transmitter output indicates 1060 transmitter output indicates 1060 watts?watts?
A.A. 530 watts530 watts
B.B. 1060 watts1060 watts
C.C. 1500 watts1500 watts
D.D. 2120 watts2120 watts
Electrical Principles69
G5B15 What is the output PEP of an G5B15 What is the output PEP of an unmodulated carrier if an average unmodulated carrier if an average reading wattmeter connected to the reading wattmeter connected to the transmitter output indicates 1060 transmitter output indicates 1060 watts?watts?
A.A. 530 watts530 watts
B.B. 1060 watts1060 wattsC.C. 1500 watts1500 watts
D.D. 2120 watts2120 watts
InductanceInductance
Electrical Principles70
Inductance is the property in an electrical circuit where a change in the electric current through that circuit induces an electromotive force (EMF) that opposes the change in current (See Induced EMF).
Electrical Principles71
G5C01 What causes a voltage to appear G5C01 What causes a voltage to appear across the secondary winding of a across the secondary winding of a transformer when an AC voltage source transformer when an AC voltage source is connected across its primary is connected across its primary winding?winding?
A.A. Capacitive couplingCapacitive coupling
B.B. Displacement current couplingDisplacement current coupling
C.C. Mutual inductanceMutual inductance
D.D. Mutual capacitanceMutual capacitance
Electrical Principles72
G5C01 What causes a voltage to appear G5C01 What causes a voltage to appear across the secondary winding of a across the secondary winding of a transformer when an AC voltage source transformer when an AC voltage source is connected across its primary is connected across its primary winding?winding?
A.A. Capacitive couplingCapacitive coupling
B.B. Displacement current couplingDisplacement current coupling
C.C. Mutual inductanceMutual inductanceD.D. Mutual capacitanceMutual capacitance
Electrical Principles73
G5C02 Where is the source of energy G5C02 Where is the source of energy normally connected in a transformer?normally connected in a transformer?
A.A. To the secondary windingTo the secondary winding
B.B. To the primary windingTo the primary winding
C.C. To the coreTo the core
D.D. To the platesTo the plates
Electrical Principles74
G5C02 Where is the source of energy G5C02 Where is the source of energy normally connected in a transformer?normally connected in a transformer?
A.A. To the secondary windingTo the secondary winding
B.B. To the primary windingTo the primary windingC.C. To the coreTo the core
D.D. To the platesTo the plates
Electrical Principles75
G5C03 What is current in the primary G5C03 What is current in the primary winding of a transformer called if no winding of a transformer called if no load is attached to the secondary?load is attached to the secondary?
A.A. Magnetizing currentMagnetizing current
B.B. Direct currentDirect current
C.C. Excitation currentExcitation current
D.D. Stabilizing currentStabilizing current
Electrical Principles76
G5C03 What is current in the primary G5C03 What is current in the primary winding of a transformer called if no winding of a transformer called if no load is attached to the secondary?load is attached to the secondary?
A.A. Magnetizing currentMagnetizing currentB.B. Direct currentDirect current
C.C. Excitation currentExcitation current
D.D. Stabilizing currentStabilizing current
Resistors in Parallel
When Resistors are connected in parallel, their combined resistance is less than the resistance of the smallest
resistor. R1*R2
Two Resistors formula RT = --------- (Product of over Sum) R1+R2
1 1 1 1 1
Two or more.. -- = -- + -- + -- + --
(Reciprocal) RT R1 R2 R3 R……
Electrical Principles79
G5C04 What is the total resistance of G5C04 What is the total resistance of three 100-ohm resistors in parallel?three 100-ohm resistors in parallel?
A.A. .30 ohms.30 ohms
B.B. .33 ohms.33 ohms
C.C. 33.3 ohms33.3 ohms
D.D. 300 ohms300 ohms
Electrical Principles80
G5C04 What is the total resistance of G5C04 What is the total resistance of three 100-ohm resistors in parallel?three 100-ohm resistors in parallel?
A.A. .30 ohms.30 ohms
B.B. .33 ohms.33 ohms
C.C. 33.3 ohms33.3 ohmsD.D. 300 ohms300 ohms
Electrical Principles81
G5C05 What is the value of each G5C05 What is the value of each resistor if three equal value resistors in resistor if three equal value resistors in parallel produce 50 ohms of resistance, parallel produce 50 ohms of resistance, and the same three resistors in series and the same three resistors in series produce 450 ohms?produce 450 ohms?
A.A. 1500 ohms1500 ohms
B.B. 90 ohms90 ohms
C.C. 150 ohms150 ohms
D.D. 175 ohms175 ohms
Electrical Principles82
G5C05 What is the value of each G5C05 What is the value of each resistor if three equal value resistors in resistor if three equal value resistors in parallel produce 50 ohms of resistance, parallel produce 50 ohms of resistance, and the same three resistors in series and the same three resistors in series produce 450 ohms?produce 450 ohms?
A.A. 1500 ohms1500 ohms
B.B. 90 ohms90 ohms
C.C. 150 ohms150 ohmsD.D. 175 ohms175 ohms
Transformers Isolation / Matching
Isolation – Unity turns ratio Same number of turns in the secondary
as in the primary.
MatchingStep Up or Step Down Step up… More windings in
Secondary Step Down…More windings in Primary
Calculating Turns Ratio
Each winding of a transformer contains a certain number of turns of wire. The turns ratio is defined
as the ratio of turns of wire in the primary winding to the number of turns of wire in the secondary
winding. Turns ratio can be expressed using the formula
Np
Ratio = ------ Ns
Np = Number of turns in the PrimaryNs = Number of turns in the Secondary
Electrical Principles85
G5C06 What is the voltage across a G5C06 What is the voltage across a 500-turn secondary winding in a 500-turn secondary winding in a transformer if the 2250-turn primary is transformer if the 2250-turn primary is connected to 120 VAC?connected to 120 VAC?
A.A. 2370 volts2370 volts
B.B. 540 volts540 volts
C.C. 26.7 volts26.7 volts
D.D. 5.9 volts5.9 volts
Electrical Principles86
G5C06 What is the voltage across a G5C06 What is the voltage across a 500-turn secondary winding in a 500-turn secondary winding in a transformer if the 2250-turn primary is transformer if the 2250-turn primary is connected to 120 VAC?connected to 120 VAC?
A.A. 2370 volts2370 volts
B.B. 540 volts540 volts
C.C. 26.7 volts26.7 voltsD.D. 5.9 volts5.9 volts
Impedance MatchingMaximum power is transferred from one circuit to
another through a transformer when the impedances are equal, or matched. A transformer winding constructed with a definite turns ratio can perform an impedance matching function. The turns ratio will establish the proper relationship between the primary and secondary winding impedances.
The ratio between the two impedances is referred to as the impedance ratio and is expressed by using the following equation.
Np Zp --- = ---- Ns Zs
Where Np = Number of turns in Primary Ns = Number of turns in Secondary Zp = Impedance of Primary Zs = Impedance of Secondary
Electrical Principles88
G5C07 What is the turns ratio of a G5C07 What is the turns ratio of a transformer used to match an audio transformer used to match an audio amplifier having a 600-ohm output amplifier having a 600-ohm output impedance to a speaker having a 4-ohm impedance to a speaker having a 4-ohm impedance?impedance?
A.A. 12.2 to 112.2 to 1
B.B. 24.4 to 124.4 to 1
C.C. 150 to 1150 to 1
D.D. 300 to 1300 to 1
Electrical Principles89
G5C07 What is the turns ratio of a G5C07 What is the turns ratio of a transformer used to match an audio transformer used to match an audio amplifier having a 600-ohm output amplifier having a 600-ohm output impedance to a speaker having a 4-ohm impedance to a speaker having a 4-ohm impedance?impedance?
A.A. 12.2 to 112.2 to 1B.B. 24.4 to 124.4 to 1
C.C. 150 to 1150 to 1
D.D. 300 to 1300 to 1
Capacitors in Series
When capacitors are connected in series, the total capacitance is less than any one of the series capacitors' individual capacitances. If two or more capacitors are connected in series, the overall effect is that of a single (equivalent) capacitor having the sum total of the plate spacings of the individual capacitors. An increase in plate spacing, with all other factors unchanged, results in decreased capacitance. C1*C2 Two Capacitors CT = --------- C1+C2
Two or more.. 1 1 1 1 1 -- = -- + -- + -- + -- CT C1 C2 C3 C……
Capacitors in Parallel
When capacitors are connected in parallel, the total capacitance is the sum of the individual capacitors' capacitances. If two or more capacitors are connected in parallel, the overall effect is that of a single equivalent capacitor having the sum total of the plate areas of the individual capacitors. An increase in plate area, with all other factors unchanged, results in increased capacitance.
Capacitors in Parallel are additive.
CT = C1 + C 2 + C3 +C...
Inductors in SeriesWhen inductors are connected in series, the total inductance
is the sum of the individual inductors' inductances. The definitive measure of inductance is the amount of voltage dropped across an inductor for a given rate of current change through it. If inductors are connected together in series (thus sharing the same current, and seeing the same rate of change in current), then the total voltage dropped as the result of a change in current will be additive with each inductor, creating a greater total voltage than either of the individual inductors alone. Greater voltage for the same rate of change in current means greater inductance.
Inductors in Series are additive.
LT = L1 + L 2 + L3 +L...
Inductors in ParallelWhen inductors are connected in parallel, the total inductance is
less than any one of the parallel inductors' inductances. Rremember that the definitive measure of inductance is the amount of voltage dropped across an inductor for a given rate of current change through it. Since the current through each parallel inductor will be a fraction of the total current, and the voltage across each parallel inductor will be equal, a change in total current will result in less voltage dropped across the parallel array than for any one of the inductors considered separately. In other words, there will be less voltage dropped across parallel inductors for a given rate of change in current than for any of those inductors considered separately, because total current divides among parallel branches. Less voltage for the same rate of change in current means less inductance.
1 1 1 1 1Two or more.. -- = -- + -- + -- + --(Reciprocal) LT L1 L2 L3 L……
Electrical Principles94
G5C08 What is the equivalent G5C08 What is the equivalent capacitance of two 5000 picofarad capacitance of two 5000 picofarad capacitors and one 750 picofarad capacitors and one 750 picofarad capacitor connected in capacitor connected in parallelparallel??
A.A. 576.9 picofarads576.9 picofarads
B.B. 1733 picofarads1733 picofarads
C.C. 3583 picofarads3583 picofarads
D.D. 10750 picofarads10750 picofarads
Electrical Principles95
G5C08 What is the equivalent G5C08 What is the equivalent capacitance of two 5000 picofarad capacitance of two 5000 picofarad capacitors and one 750 picofarad capacitors and one 750 picofarad capacitor connected in parallel?capacitor connected in parallel?
A.A. 576.9 picofarads576.9 picofarads
B.B. 1733 picofarads1733 picofarads
C.C. 3583 picofarads3583 picofarads
D.D. 10750 picofarads10750 picofarads
Electrical Principles96
G5C09 What is the capacitance of three G5C09 What is the capacitance of three 100 microfarad capacitors connected in 100 microfarad capacitors connected in series?series?
A.A. .30 microfarads.30 microfarads
B.B. .33 microfarads.33 microfarads
C.C. 33.3 microfarads33.3 microfarads
D.D. 300 microfarads300 microfarads
Electrical Principles97
G5C09 What is the capacitance of three G5C09 What is the capacitance of three 100 microfarad capacitors connected in 100 microfarad capacitors connected in series?series?
A.A. .30 microfarads.30 microfarads
B.B. .33 microfarads.33 microfarads
C.C. 33.3 microfarads33.3 microfaradsD.D. 300 microfarads300 microfarads
Electrical Principles98
G5C10 What is the inductance of three G5C10 What is the inductance of three 10 millihenry inductors connected in 10 millihenry inductors connected in parallel?parallel?
A.A. .30 Henrys.30 Henrys
B.B. 3.3 Henrys3.3 Henrys
C.C. 3.3 millihenrys3.3 millihenrys
D.D. 30 millihenrys30 millihenrys
Electrical Principles99
G5C10 What is the inductance of three G5C10 What is the inductance of three 10 millihenry inductors connected in 10 millihenry inductors connected in parallel?parallel?
C.C. 3.3 millihenrys3.3 millihenrys
Electrical Principles100
G5C11 What is the inductance of a 20 G5C11 What is the inductance of a 20 millihenry inductor in millihenry inductor in seriesseries with a 50 with a 50 millihenry inductor?millihenry inductor?
A.A. .07 millihenrys.07 millihenrys
B.B. 14.3 millihenrys14.3 millihenrys
C.C. 70 millihenrys70 millihenrys
D.D. 1000 millihenrys1000 millihenrys
Electrical Principles101
G5C11 What is the inductance of a 20 G5C11 What is the inductance of a 20 millihenry inductor in series with a 50 millihenry inductor in series with a 50 millihenry inductor?millihenry inductor?
A.A. .07 millihenrys.07 millihenrys
B.B. 14.3 millihenrys14.3 millihenrys
C.C. 70 millihenrys70 millihenrysD.D. 1000 millihenrys1000 millihenrys
Electrical Principles102
G5C12 What is the capacitance of a 20 G5C12 What is the capacitance of a 20 microfarad capacitor in microfarad capacitor in seriesseries with a 50 with a 50 microfarad capacitor?microfarad capacitor?
A.A. .07 microfarads.07 microfarads
B.B. 14.3 microfarads14.3 microfarads
C.C. 70 microfarads70 microfarads
D.D. 1000 microfarads1000 microfarads
Electrical Principles103
G5C12 What is the capacitance of a 20 G5C12 What is the capacitance of a 20 microfarad capacitor in series with a 50 microfarad capacitor in series with a 50 microfarad capacitor?microfarad capacitor?
A.A. .07 microfarads.07 microfarads
B.B. 14.3 microfarads14.3 microfaradsC.C. 70 microfarads70 microfarads
D.D. 1000 microfarads1000 microfarads
Electrical Principles104
G5C13 What component should be G5C13 What component should be added to a capacitor in a circuit to added to a capacitor in a circuit to increase the circuit capacitance?increase the circuit capacitance?
A.A. An inductor in seriesAn inductor in series
B.B. A resistor in seriesA resistor in series
C.C. A capacitor in parallelA capacitor in parallel
D.D. A capacitor in seriesA capacitor in series
Electrical Principles105
G5C13 What component should be G5C13 What component should be added to a capacitor in a circuit to added to a capacitor in a circuit to increase the circuit capacitance?increase the circuit capacitance?
A.A. An inductor in seriesAn inductor in series
B.B. A resistor in seriesA resistor in series
C.C. A capacitor in parallelA capacitor in parallelD.D. A capacitor in seriesA capacitor in series
Electrical Principles106
G5C14 What component should be G5C14 What component should be added to an inductor in a circuit to added to an inductor in a circuit to increase the circuit inductance?increase the circuit inductance?
A.A. A capacitor in seriesA capacitor in series
B.B. A resistor in parallelA resistor in parallel
C.C. An inductor in parallelAn inductor in parallel
D.D. An inductor in seriesAn inductor in series
Electrical Principles107
G5C14 What component should be G5C14 What component should be added to an inductor in a circuit to added to an inductor in a circuit to increase the circuit inductance?increase the circuit inductance?
A.A. A capacitor in seriesA capacitor in series
B.B. A resistor in parallelA resistor in parallel
C.C. An inductor in parallelAn inductor in parallel
D.D. An inductor in seriesAn inductor in series
Electrical Principles108
G5C15 What is the total resistance of a G5C15 What is the total resistance of a 10 ohm, a 20 ohm, and a 50 ohm 10 ohm, a 20 ohm, and a 50 ohm resistor in resistor in parallelparallel??
A.A. 5.9 ohms5.9 ohms
B.B. 0.17 ohms0.17 ohms
C.C. 10000 ohms10000 ohms
D.D. 80 ohms80 ohms
Electrical Principles109
G5C15 What is the total resistance of a G5C15 What is the total resistance of a 10 ohm, a 20 ohm, and a 50 ohm 10 ohm, a 20 ohm, and a 50 ohm resistor in parallel?resistor in parallel?
A.A. 5.9 ohms5.9 ohmsB.B. 0.17 ohms0.17 ohms
C.C. 10000 ohms10000 ohms
D.D. 80 ohms80 ohms
Electrical Principles110
G5C16 What component should be G5C16 What component should be added to an existing resistor in a circuit added to an existing resistor in a circuit to increase circuit resistance?to increase circuit resistance?
A.A. A resistor in parallelA resistor in parallel
B.B. A resistor in seriesA resistor in series
C.C. A capacitor in seriesA capacitor in series
D.D. A capacitor in parallelA capacitor in parallel
Electrical Principles111
G5C16 What component should be G5C16 What component should be added to an existing resistor in a circuit added to an existing resistor in a circuit to increase circuit resistance?to increase circuit resistance?
A.A. A resistor in parallelA resistor in parallel
B.B. A resistor in seriesA resistor in seriesC.C. A capacitor in seriesA capacitor in series
D.D. A capacitor in parallelA capacitor in parallel
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