Practical Circuits1

G7 - PRACTICAL CIRCUITS G7 - PRACTICAL CIRCUITS [2 exam question - 2 groups] [2 exam question - 2 groups]

G7AG7A Power supplies; transmitters and receivers; filters; Power supplies; transmitters and receivers; filters; schematic symbolsschematic symbols

G7BG7B Digital circuits (gates, flip-flops, shift registers); Digital circuits (gates, flip-flops, shift registers); amplifiers and oscillators amplifiers and oscillators

G7A Power suppliesG7A Power supplies

• A power-supply bleeder resistor A power-supply bleeder resistor discharges the discharges the filter capacitors providing a safety featurefilter capacitors providing a safety feature

• Capacitors and inductors Capacitors and inductors are used in a power-are used in a power-supply filter networksupply filter network

• The minimum peak-inverse-voltage rating of The minimum peak-inverse-voltage rating of the rectifier in a full-wave power supply the rectifier in a full-wave power supply should be double the normal peak output voltage should be double the normal peak output voltage of the power supplyof the power supply

• The approximate minimum peak-inverse-The approximate minimum peak-inverse-voltage rating of the rectifier in a half-wave voltage rating of the rectifier in a half-wave power supply power supply should be two times the normal should be two times the normal peak output voltage of the power supplypeak output voltage of the power supply

Practical Circuits2

G7A Power supplies cont’dG7A Power supplies cont’d• A desirable characteristic for capacitors used A desirable characteristic for capacitors used

to filter the DC output of a switching power to filter the DC output of a switching power supply supply is low equivalent series resistanceis low equivalent series resistance

• An advantage of a switched-mode power An advantage of a switched-mode power supply as compared to a linear power supply supply as compared to a linear power supply is is high frequency operation allows the use of smaller high frequency operation allows the use of smaller componentscomponents

• A 180 degree portion of the AC cycle A 180 degree portion of the AC cycle is is converted to DC by a half-wave rectifierconverted to DC by a half-wave rectifier

• A 360 degree portion of the AC cycleA 360 degree portion of the AC cycle is is converted to DC by a full-wave rectifierconverted to DC by a full-wave rectifier

• The output waveform of an unfiltered full-wave The output waveform of an unfiltered full-wave rectifier connected to a resistive load rectifier connected to a resistive load is a series is a series of DC pulses at twice the frequency of the AC inputof DC pulses at twice the frequency of the AC input

Practical Circuits3

7A Transmitters7A Transmitters

• A Balanced modulator circuit A Balanced modulator circuit is used to is used to combine signals from the carrier oscillator and combine signals from the carrier oscillator and speech amplifier and send the result to the filter in speech amplifier and send the result to the filter in a typical single-sideband phone transmittera typical single-sideband phone transmitter

• An advantage of a crystal controlled An advantage of a crystal controlled transmitter transmitter is stable output frequencyis stable output frequency

Practical Circuits4

G7A ReceiversG7A Receivers

• A Mixer circuit A Mixer circuit is used to process signals from the is used to process signals from the RF amplifier and local oscillator and send the RF amplifier and local oscillator and send the results to the IF filter in a super heterodyne results to the IF filter in a super heterodyne receiverreceiver

• A Product detector circuit A Product detector circuit is used to process is used to process signals from the IF amplifier and BFO and send the signals from the IF amplifier and BFO and send the result to the AF amplifier in a single-sideband result to the AF amplifier in a single-sideband phone superheterodyne receiverphone superheterodyne receiver

• The simplest combination of stages that can The simplest combination of stages that can be combined to implement a be combined to implement a superhedterodyne receiver superhedterodyne receiver is an HF oscillator, is an HF oscillator, mixer, and detectormixer, and detector

Practical Circuits5

G7A Receivers cont’dG7A Receivers cont’d

• A direct conversion receiver A direct conversion receiver is suitable for CW is suitable for CW and SSB reception but does not require a mixer and SSB reception but does not require a mixer stage or an IF amplifierstage or an IF amplifier

• A Discriminator circuit A Discriminator circuit is used in many FM is used in many FM receivers to convert signals coming from the IF receivers to convert signals coming from the IF amplifier to audioamplifier to audio

Practical Circuits6

G7A FiltersG7A Filters

• The impedance of a low-pass filter as The impedance of a low-pass filter as compared to the impedance of the compared to the impedance of the transmission line into which it is to be transmission line into which it is to be inserted inserted should be about the sameshould be about the same

• A Filter A Filter might be used to process signals from the might be used to process signals from the balanced modulator and send them to the mixer in balanced modulator and send them to the mixer in a single-sideband phone transmittera single-sideband phone transmitter

Practical Circuits7

G7A Schematic drawing symbolsG7A Schematic drawing symbols

3. Fixed 3. Fixed resistorresistor

4. NPN 4. NPN TransistorTransistor

5. Variable 5. Variable capacitorcapacitor

6. Transformer6. Transformer

11. Single pole 11. Single pole switchswitch

13. Single cell 13. Single cell batterybattery

Practical Circuits8

Practical Circuits9

G7A01 What safety feature does a G7A01 What safety feature does a power-supply bleeder resistor provide?power-supply bleeder resistor provide?

A.A. It acts as a fuse for excess voltageIt acts as a fuse for excess voltage

B.B. It discharges the filter capacitorsIt discharges the filter capacitors

C.C. It removes shock hazards from the induction coilsIt removes shock hazards from the induction coils

D.D. It eliminates ground-loop currentIt eliminates ground-loop current

Practical Circuits10

G7A01 What safety feature does a G7A01 What safety feature does a power-supply bleeder resistor provide?power-supply bleeder resistor provide?

A.A. It acts as a fuse for excess voltageIt acts as a fuse for excess voltage

B.B. It discharges the filter capacitorsIt discharges the filter capacitorsC.C. It removes shock hazards from the induction coilsIt removes shock hazards from the induction coils

D.D. It eliminates ground-loop currentIt eliminates ground-loop current

Practical Circuits11

G7A02 What components are used in a G7A02 What components are used in a power-supply filter network?power-supply filter network?

A.A. DiodesDiodes

B.B. Transformers and transistorsTransformers and transistors

C.C. Quartz crystalsQuartz crystals

D.D. Capacitors and inductorsCapacitors and inductors

Practical Circuits12

G7A02 What components are used in a G7A02 What components are used in a power-supply filter network?power-supply filter network?

A.A. DiodesDiodes

B.B. Transformers and transistorsTransformers and transistors

C.C. Quartz crystalsQuartz crystals

D.D. Capacitors and inductorsCapacitors and inductors

Practical Circuits13

G7A03 What should be the minimum G7A03 What should be the minimum peak-inverse-voltage rating of the peak-inverse-voltage rating of the rectifier in a full-wave power supply?rectifier in a full-wave power supply?

A.A. One-quarter the normal output voltage of the power One-quarter the normal output voltage of the power supplysupply

B.B. Half the normal output voltage of the power supplyHalf the normal output voltage of the power supply

C.C. Double the normal peak output voltage of the Double the normal peak output voltage of the power supplypower supply

D.D. Equal to the normal output voltage of the power Equal to the normal output voltage of the power supplysupply

Practical Circuits14

G7A03 What should be the minimum G7A03 What should be the minimum peak-inverse-voltage rating of the peak-inverse-voltage rating of the rectifier in a full-wave power supply?rectifier in a full-wave power supply?

A.A. One-quarter the normal output voltage of the power One-quarter the normal output voltage of the power supplysupply

B.B. Half the normal output voltage of the power supplyHalf the normal output voltage of the power supply

C.C. Double the normal peak output voltage of Double the normal peak output voltage of the power supplythe power supply

D.D. Equal to the normal output voltage of the power Equal to the normal output voltage of the power supplysupply

Practical Circuits15

G7A04 What should be the approximate G7A04 What should be the approximate minimum peak-inverse-voltage rating minimum peak-inverse-voltage rating of the rectifier in a half-wave power of the rectifier in a half-wave power supply?supply?

A.A. One-half the normal peak output voltage of the One-half the normal peak output voltage of the power supplypower supply

B.B. Half the normal output voltage of the power supplyHalf the normal output voltage of the power supply

C.C. Equal to the normal output voltage of the power Equal to the normal output voltage of the power supplysupply

D.D. Two times the normal peak output voltage of the Two times the normal peak output voltage of the power supplypower supply

Practical Circuits16

G7A04 What should be the approximate G7A04 What should be the approximate minimum peak-inverse-voltage rating minimum peak-inverse-voltage rating of the rectifier in a half-wave power of the rectifier in a half-wave power supply?supply?

A.A. One-half the normal peak output voltage of the One-half the normal peak output voltage of the power supplypower supply

B.B. Half the normal output voltage of the power supplyHalf the normal output voltage of the power supply

C.C. Equal to the normal output voltage of the power Equal to the normal output voltage of the power supplysupply

D.D. Two times the normal peak output voltage Two times the normal peak output voltage of the power supplyof the power supply

Practical Circuits17

G7A05 What should be the impedance G7A05 What should be the impedance of a low-pass filter as compared to the of a low-pass filter as compared to the impedance of the transmission line into impedance of the transmission line into which it is inserted?which it is inserted?

A.A. Substantially higherSubstantially higher

B.B. About the sameAbout the same

C.C. Substantially lowerSubstantially lower

D.D. Twice the transmission line impedanceTwice the transmission line impedance

Practical Circuits18

G7A05 What should be the impedance G7A05 What should be the impedance of a low-pass filter as compared to the of a low-pass filter as compared to the impedance of the transmission line into impedance of the transmission line into which it is inserted?which it is inserted?

A.A. Substantially higherSubstantially higher

B.B. About the sameAbout the sameC.C. Substantially lowerSubstantially lower

D.D. Twice the transmission line impedanceTwice the transmission line impedance

Practical Circuits19

G7A06 Which of the following might be G7A06 Which of the following might be used to process signals from the used to process signals from the balanced modulator and send them to balanced modulator and send them to the mixer in a single-sideband phone the mixer in a single-sideband phone transmitter?transmitter?

A.A. Carrier oscillatorCarrier oscillator

B.B. FilterFilter

C.C. IF amplifierIF amplifier

D.D. RF amplifierRF amplifier

Practical Circuits20

G7A06 Which of the following might be G7A06 Which of the following might be used to process signals from the used to process signals from the balanced modulator and send them to balanced modulator and send them to the mixer in a single-sideband phone the mixer in a single-sideband phone transmitter?transmitter?

MicSpeech

AmpBalancedModulator

CarrierOscillator

LSB USB

IF Filter

IF Amp

IF Mixer

VFO Mixer

IF Amp

Power Amp

SecondOscillator VFO

Antenna

Practical Circuits21

G7A06 Which of the following might be G7A06 Which of the following might be used to process signals from the used to process signals from the balanced modulator and send them to balanced modulator and send them to the mixer in a single-sideband phone the mixer in a single-sideband phone transmitter?transmitter?

A.A. Carrier oscillatorCarrier oscillator

B.B. FilterFilterC.C. IF amplifierIF amplifier

D.D. RF amplifierRF amplifier

MicSpeech

AmpBalancedModulator

CarrierOscillator

LSB USB

IF Filter

IF Amp

IF Mixer

VFO Mixer

IF Amp

Power Amp

SecondOscillator VFO

Antenna

Practical Circuits22

G7A07 Which circuit is used to combine G7A07 Which circuit is used to combine signals from the carrier oscillator and signals from the carrier oscillator and speech amplifier and send the result to speech amplifier and send the result to the filter in a typical single-sideband the filter in a typical single-sideband phone transmitter?phone transmitter?

A.A. MixerMixer

B.B. DetectorDetector

C.C. IF amplifierIF amplifier

D.D. Balanced modulatorBalanced modulator

Practical Circuits23

G7A07 Which circuit is used to combine G7A07 Which circuit is used to combine signals from the carrier oscillator and signals from the carrier oscillator and speech amplifier and send the result to speech amplifier and send the result to the filter in a typical single-sideband the filter in a typical single-sideband phone transmitter?phone transmitter?

A.A. MixerMixer

B.B. DetectorDetector

C.C. IF amplifierIF amplifier

D.D. Balanced modulatorBalanced modulator

MicSpeech

AmpBalancedModulator

CarrierOscillator

LSB USB

IF Filter

IF Amp

IF Mixer

VFO Mixer

IF Amp

Power Amp

SecondOscillator VFO

Antenna

Practical Circuits24

G7A08 What circuit is used to process G7A08 What circuit is used to process signals from the RF amplifier and local signals from the RF amplifier and local oscillator and send the result to the IF oscillator and send the result to the IF filter in a superheterodyne receiver?filter in a superheterodyne receiver?

A.A. Balanced modulatorBalanced modulator

B.B. IF amplifierIF amplifier

C.C. MixerMixer

D.D. DetectorDetector

Practical Circuits25

G7A08 What circuit is used to process G7A08 What circuit is used to process signals from the RF amplifier and local signals from the RF amplifier and local oscillator and send the result to the IF oscillator and send the result to the IF filter in a superheterodyne receiver?filter in a superheterodyne receiver?

A.A. Balanced modulatorBalanced modulator

B.B. IF amplifierIF amplifier

C.C. MixerMixerD.D. DetectorDetector

Practical Circuits26

G7A09 What circuit is used to process G7A09 What circuit is used to process signals from the IF amplifier and BFO signals from the IF amplifier and BFO and send the result to the AF amplifier and send the result to the AF amplifier in a single-sideband phone in a single-sideband phone superheterodyne receiver?superheterodyne receiver?

A.A. RF oscillatorRF oscillator

B.B. IF filterIF filter

C.C. Balanced modulatorBalanced modulator

D.D. Product detectorProduct detector

Practical Circuits27

G7A09 What circuit is used to process G7A09 What circuit is used to process signals from the IF amplifier and BFO signals from the IF amplifier and BFO and send the result to the AF amplifier and send the result to the AF amplifier in a single-sideband phone in a single-sideband phone superheterodyne receiver?superheterodyne receiver?

A.A. RF oscillatorRF oscillator

B.B. IF filterIF filter

C.C. Balanced modulatorBalanced modulator

D.D. Product detectorProduct detector

Practical Circuits28

G7A10 What is an advantage of a G7A10 What is an advantage of a crystal controlled transmitter?crystal controlled transmitter?

A.A. Stable output frequencyStable output frequency

B.B. Excellent modulation clarityExcellent modulation clarity

C.C. Ease of switching between bandsEase of switching between bands

D.D. Ease of changing frequencyEase of changing frequency

Practical Circuits29

G7A10 What is an advantage of a G7A10 What is an advantage of a crystal controlled transmitter?crystal controlled transmitter?

A.A. Stable output frequencyStable output frequencyB.B. Excellent modulation clarityExcellent modulation clarity

C.C. Ease of switching between bandsEase of switching between bands

D.D. Ease of changing frequencyEase of changing frequency

Practical Circuits30

G7A11 What is the simplest G7A11 What is the simplest combination of stages that can be combination of stages that can be combined to implement a combined to implement a superheterodyne receiver?superheterodyne receiver?

A.A. RF amplifier, detector, audio amplifierRF amplifier, detector, audio amplifier

B.B. RF amplifier, mixer, if amplifierRF amplifier, mixer, if amplifier

C.C. HF oscillator, mixer, detectorHF oscillator, mixer, detector

D.D. HF oscillator, product detector, audio amplifierHF oscillator, product detector, audio amplifier

Practical Circuits31

G7A11 What is the simplest G7A11 What is the simplest combination of stages that can be combination of stages that can be combined to implement a combined to implement a superheterodyne receiver?superheterodyne receiver?

A.A. RF amplifier, detector, audio amplifierRF amplifier, detector, audio amplifier

B.B. RF amplifier, mixer, if amplifierRF amplifier, mixer, if amplifier

C.C. HF oscillator, mixer, detectorHF oscillator, mixer, detectorD.D. HF oscillator, product detector, audio amplifierHF oscillator, product detector, audio amplifier

Practical Circuits32

G7A12 What type of receiver is suitable G7A12 What type of receiver is suitable for CW and SSB reception but does not for CW and SSB reception but does not require a mixer stage or an IF require a mixer stage or an IF amplifier?amplifier?

A.A. A super-regenerative receiverA super-regenerative receiver

B.B. A TRF receiverA TRF receiver

C.C. A super-heterodyne receiverA super-heterodyne receiver

D.D. A direct conversion receiverA direct conversion receiver

Practical Circuits33

G7A12 What type of receiver is suitable G7A12 What type of receiver is suitable for CW and SSB reception but does not for CW and SSB reception but does not require a mixer stage or an IF require a mixer stage or an IF amplifier?amplifier?

A.A. A super-regenerative receiverA super-regenerative receiver

B.B. A TRF receiverA TRF receiver

C.C. A super-heterodyne receiverA super-heterodyne receiver

D.D. A direct conversion receiverA direct conversion receiver

Practical Circuits34

G7A13 What type of circuit is used in G7A13 What type of circuit is used in many FM receivers to convert signals many FM receivers to convert signals coming from the IF amplifier to audio?coming from the IF amplifier to audio?

A.A. Product detectorProduct detector

B.B. Phase inverterPhase inverter

C.C. MixerMixer

D.D. DiscriminatorDiscriminator

Practical Circuits35

G7A13 What type of circuit is used in G7A13 What type of circuit is used in many FM receivers to convert signals many FM receivers to convert signals coming from the IF amplifier to audio?coming from the IF amplifier to audio?

A.A. Product detectorProduct detector

B.B. Phase inverterPhase inverter

C.C. MixerMixer

D.D. DiscriminatorDiscriminator

Practical Circuits36

G7A14 Which of the following is a G7A14 Which of the following is a desirable characteristic for capacitors desirable characteristic for capacitors used to filter the DC output of a used to filter the DC output of a switching power supply?switching power supply?

A.A. Low equivalent series resistanceLow equivalent series resistance

B.B. High equivalent series resistanceHigh equivalent series resistance

C.C. Low Temperature coefficientLow Temperature coefficient

D.D. High Temperature coefficientHigh Temperature coefficient

Practical Circuits37

G7A14 Which of the following is a G7A14 Which of the following is a desirable characteristic for capacitors desirable characteristic for capacitors used to filter the DC output of a used to filter the DC output of a switching power supply?switching power supply?

A.A. Low equivalent series resistanceLow equivalent series resistanceB.B. High equivalent series resistanceHigh equivalent series resistance

C.C. Low Temperature coefficientLow Temperature coefficient

D.D. High Temperature coefficientHigh Temperature coefficient

Practical Circuits38

G7A15 Which of the following is an G7A15 Which of the following is an advantage of a switched-mode power advantage of a switched-mode power supply as compared to a linear power supply as compared to a linear power supply?supply?

A.A. Faster switching time makes higher output voltage Faster switching time makes higher output voltage possiblepossible

B.B. Fewer circuit components are requiredFewer circuit components are required

C.C. High frequency operation allows the use of smaller High frequency operation allows the use of smaller componentscomponents

D.D. All of these choices are correctAll of these choices are correct

Practical Circuits39

G7A15 Which of the following is an G7A15 Which of the following is an advantage of a switched-mode power advantage of a switched-mode power supply as compared to a linear power supply as compared to a linear power supply?supply?

A.A. Faster switching time makes higher output voltage Faster switching time makes higher output voltage possiblepossible

B.B. Fewer circuit components are requiredFewer circuit components are required

C.C. High frequency operation allows the use High frequency operation allows the use of smaller componentsof smaller components

D.D. All of these choices are correctAll of these choices are correct

Practical Circuits40

Half Wave RectifierHalf Wave Rectifier

Practical Circuits41

G7A16 What portion of the AC cycle is G7A16 What portion of the AC cycle is converted to DC by a half-wave converted to DC by a half-wave rectifier?rectifier?

A.A. 90 degrees90 degrees

B.B. 180 degrees180 degrees

C.C. 270 degrees270 degrees

D.D. 360 degrees360 degrees

Practical Circuits42

G7A16 What portion of the AC cycle is G7A16 What portion of the AC cycle is converted to DC by a half-wave converted to DC by a half-wave rectifier?rectifier?

A.A. 90 degrees90 degrees

B.B. 180 degrees180 degreesC.C. 270 degrees270 degrees

D.D. 360 degrees360 degrees

Practical Circuits43

G7A17 What portion of the AC cycle is G7A17 What portion of the AC cycle is converted to DC by a full-wave converted to DC by a full-wave rectifier?rectifier?

A.A. 90 degrees90 degrees

B.B. 180 degrees180 degrees

C.C. 270 degrees270 degrees

D.D. 360 degrees360 degrees

Practical Circuits44

G7A17 What portion of the AC cycle is G7A17 What portion of the AC cycle is converted to DC by a full-wave converted to DC by a full-wave rectifier?rectifier?

A.A. 90 degrees90 degrees

B.B. 180 degrees180 degrees

C.C. 270 degrees270 degrees

D.D. 360 degrees360 degrees

Practical Circuits45

G7A18 What is the output waveform of G7A18 What is the output waveform of an unfiltered full-wave rectifier an unfiltered full-wave rectifier connected to a resistive load?connected to a resistive load?

A.A. A series of DC pulses at twice the frequency of the A series of DC pulses at twice the frequency of the AC inputAC input

B.B. A series of DC pulses at the same frequency as the A series of DC pulses at the same frequency as the AC inputAC input

C.C. A sine wave at half the frequency of the AC inputA sine wave at half the frequency of the AC input

D.D. A steady DC voltageA steady DC voltage

Practical Circuits46

G7A18 What is the output waveform of G7A18 What is the output waveform of an unfiltered full-wave rectifier an unfiltered full-wave rectifier connected to a resistive load?connected to a resistive load?

A.A. A series of DC pulses at twice the A series of DC pulses at twice the frequency of the AC inputfrequency of the AC input

B.B. A series of DC pulses at the same frequency as the A series of DC pulses at the same frequency as the AC inputAC input

C.C. A sine wave at half the frequency of the AC inputA sine wave at half the frequency of the AC input

D.D. A steady DC voltageA steady DC voltage

Practical Circuits47

G7A19 Which symbol in figure G7-1 G7A19 Which symbol in figure G7-1 represents a fixed resistor?represents a fixed resistor?

A.A. Symbol 2Symbol 2

B.B. Symbol 6Symbol 6

C.C. Symbol 3Symbol 3

D.D. Symbol 12Symbol 12

Practical Circuits48

G7A19 Which symbol in figure G7-1 G7A19 Which symbol in figure G7-1 represents a fixed resistor?represents a fixed resistor?

A.A. Symbol 2Symbol 2

B.B. Symbol 6Symbol 6

C.C. Symbol 3Symbol 3D.D. Symbol 12Symbol 12

Practical Circuits49

G7A20 Which symbol in figure G7-1 G7A20 Which symbol in figure G7-1 represents a single cell battery?represents a single cell battery?

A.A. Symbol 5Symbol 5

B.B. Symbol 12Symbol 12

C.C. Symbol 8Symbol 8

D.D. Symbol 13Symbol 13

Practical Circuits50

G7A20 Which symbol in figure G7-1 G7A20 Which symbol in figure G7-1 represents a single cell battery?represents a single cell battery?

A.A. Symbol 5Symbol 5

B.B. Symbol 12Symbol 12

C.C. Symbol 8Symbol 8

D.D. Symbol 13Symbol 13

Practical Circuits51

G7A21 Which symbol in figure G7-1 G7A21 Which symbol in figure G7-1 represents a NPN transistor?represents a NPN transistor?

A.A. Symbol 2Symbol 2

B.B. Symbol 4Symbol 4

C.C. Symbol 10Symbol 10

D.D. Symbol 12Symbol 12

Practical Circuits52

G7A21 Which symbol in figure G7-1 G7A21 Which symbol in figure G7-1 represents a NPN transistor?represents a NPN transistor?

A.A. Symbol 2Symbol 2

B.B. Symbol 4Symbol 4C.C. Symbol 10Symbol 10

D.D. Symbol 12Symbol 12

Practical Circuits53

G7A22 Which symbol in figure G7-1 G7A22 Which symbol in figure G7-1 represents a variable capacitor?represents a variable capacitor?

A.A. Symbol 2Symbol 2

B.B. Symbol 11Symbol 11

C.C. Symbol 5Symbol 5

D.D. Symbol 12Symbol 12

Practical Circuits54

G7A22 Which symbol in figure G7-1 G7A22 Which symbol in figure G7-1 represents a variable capacitor?represents a variable capacitor?

A.A. Symbol 2Symbol 2

B.B. Symbol 11Symbol 11

C.C. Symbol 5Symbol 5D.D. Symbol 12Symbol 12

Practical Circuits55

G7A23 Which symbol in figure G7-1 G7A23 Which symbol in figure G7-1 represents a transformer?represents a transformer?

A.A. Symbol 6Symbol 6

B.B. Symbol 4Symbol 4

C.C. Symbol 10Symbol 10

D.D. symbol 2symbol 2

Practical Circuits56

G7A23 Which symbol in figure G7-1 G7A23 Which symbol in figure G7-1 represents a transformer?represents a transformer?

A.A. Symbol 6Symbol 6B.B. Symbol 4Symbol 4

C.C. Symbol 10Symbol 10

D.D. symbol 2symbol 2

Practical Circuits57

G7A24 Which symbol in figure G7-1 G7A24 Which symbol in figure G7-1 represents a single pole switch?represents a single pole switch?

A.A. Symbol 2Symbol 2

B.B. Symbol 3Symbol 3

C.C. Symbol 11Symbol 11

D.D. Symbol 12Symbol 12

Practical Circuits58

G7A24 Which symbol in figure G7-1 G7A24 Which symbol in figure G7-1 represents a single pole switch?represents a single pole switch?

A.A. Symbol 2Symbol 2

B.B. Symbol 3Symbol 3

C.C. Symbol 11Symbol 11D.D. Symbol 12Symbol 12

G7B Digital circuits (gates, flip-flops, G7B Digital circuits (gates, flip-flops, shift registersshift registers

• A “flip-flop” circuit A “flip-flop” circuit is a digital circuit with two is a digital circuit with two stable statesstable states

• Digital circuits Digital circuits use the binary number system use the binary number system because binary “ones” and “zeros” are easy to because binary “ones” and “zeros” are easy to represent with an “on” and “off” staterepresent with an “on” and “off” state

• The output of a two-input NAND gate, given The output of a two-input NAND gate, given both inputs are “one” both inputs are “one” is Zerois Zero

Practical Circuits59

G7B Digital circuits cont’dG7B Digital circuits cont’d

• The output of a NOR gate given that both The output of a NOR gate given that both inputs are “zero” inputs are “zero” is oneis one

• There are 8 states in a 3-bit binary counterThere are 8 states in a 3-bit binary counter

• A shift register is a clocked array of circuits A shift register is a clocked array of circuits that passes data in steps along the arraythat passes data in steps along the array

Practical Circuits60

G7B AmplifiersG7B Amplifiers

• Low distortion Low distortion is a characteristic of a Class A is a characteristic of a Class A amplifieramplifier

• A Class “C” power stageA Class “C” power stage is appropriate for is appropriate for amplifying a modulated signal for the CW modeamplifying a modulated signal for the CW mode

• High efficiency High efficiency is an advantage of a Class C amplifieris an advantage of a Class C amplifier

• The efficiency of an RF power amplifier The efficiency of an RF power amplifier is is determined by dividing the RF output power by the DC determined by dividing the RF output power by the DC input powerinput power

• A linear amplifierA linear amplifier is an amplifier whose output is an amplifier whose output preserves the input waveformpreserves the input waveform

Practical Circuits61

G7B OscillatorsG7B Oscillators

• The basic components of virtually all The basic components of virtually all oscillators oscillators are a filter and and amplifier operating are a filter and and amplifier operating in a feedback loopin a feedback loop

• The phase shift of the RC feedback circuit The phase shift of the RC feedback circuit determines the frequency of an RC oscillatordetermines the frequency of an RC oscillator

* The inductance and capacitance in the tank * The inductance and capacitance in the tank circuit circuit determines the frequency of an LC determines the frequency of an LC oscillatoroscillator

Practical Circuits62

Practical Circuits63

G7B01 Which of the following describes G7B01 Which of the following describes a "flip-flop" circuit?a "flip-flop" circuit?

A.A. A transmit-receive circuitA transmit-receive circuit

B.B. A digital circuit with two stable statesA digital circuit with two stable states

C.C. An RF limiterAn RF limiter

D.D. A voice-operated switchA voice-operated switch

Practical Circuits64

G7B01 Which of the following describes G7B01 Which of the following describes a "flip-flop" circuit?a "flip-flop" circuit?

A.A. A transmit-receive circuitA transmit-receive circuit

B.B. A digital circuit with two stable statesA digital circuit with two stable statesC.C. An RF limiterAn RF limiter

D.D. A voice-operated switchA voice-operated switch

Practical Circuits65

G7B02 Why do digital circuits use the G7B02 Why do digital circuits use the binary number system?binary number system?

A.A. Binary "ones" and "zeros" are easy to represent Binary "ones" and "zeros" are easy to represent with an "on" or "off" statewith an "on" or "off" state

B.B. The binary number system is most accurateThe binary number system is most accurate

C.C. Binary numbers are more compatible with analog Binary numbers are more compatible with analog circuitrycircuitry

D.D. All of these answers are correctAll of these answers are correct

Practical Circuits66

G7B02 Why do digital circuits use the G7B02 Why do digital circuits use the binary number system?binary number system?

A.A. Binary "ones" and "zeros" are easy to Binary "ones" and "zeros" are easy to represent with an "on" or "off" staterepresent with an "on" or "off" state

B.B. The binary number system is most accurateThe binary number system is most accurate

C.C. Binary numbers are more compatible with analog Binary numbers are more compatible with analog circuitrycircuitry

D.D. All of these answers are correctAll of these answers are correct

Practical Circuits67

G7B03 What is the output of a two-G7B03 What is the output of a two-input NAND gate, given both inputs are input NAND gate, given both inputs are "one"?"one"?

A.A. TwoTwo

B.B. OneOne

C.C. ZeroZero

D.D. Minus OneMinus One

Practical Circuits68

G7B03 What is the output of a two-G7B03 What is the output of a two-input NAND gate, given both inputs are input NAND gate, given both inputs are "one"?"one"?

A.A. TwoTwo

B.B. OneOne

C.C. ZeroZeroD.D. Minus OneMinus One

Practical Circuits69

G7B04 What is the output of a NOR G7B04 What is the output of a NOR gate given that both inputs are "zero"?gate given that both inputs are "zero"?

A.A. ZeroZero

B.B. OneOne

C.C. Minus oneMinus one

D.D. The opposite from the previous stateThe opposite from the previous state

Practical Circuits70

G7B04 What is the output of a NOR G7B04 What is the output of a NOR gate given that both inputs are "zero"?gate given that both inputs are "zero"?

A.A. ZeroZero

B.B. OneOneC.C. Minus oneMinus one

D.D. The opposite from the previous stateThe opposite from the previous state

Practical Circuits71

G7B05 How many states are there in a G7B05 How many states are there in a 3-bit binary counter?3-bit binary counter?

A.A. 33

B.B. 66

C.C. 88

D.D. 1616

Practical Circuits72

G7B05 How many states are there in a G7B05 How many states are there in a 3-bit binary counter?3-bit binary counter?

A.A. 33

B.B. 66

C.C. 88D.D. 1616

Practical Circuits73

G7B06 What is a shift register?G7B06 What is a shift register?

A.A. A clocked array of circuits that passes data in steps A clocked array of circuits that passes data in steps along the arrayalong the array

B.B. An array of operational amplifiers used for tri-state An array of operational amplifiers used for tri-state arithmetic operationsarithmetic operations

C.C. A digital mixerA digital mixer

D.D. An analog mixerAn analog mixer

Practical Circuits74

G7B06 What is a shift register?G7B06 What is a shift register?

A.A. A clocked array of circuits that passes A clocked array of circuits that passes data in steps along the arraydata in steps along the array

B.B. An array of operational amplifiers used for tri-state An array of operational amplifiers used for tri-state arithmetic operationsarithmetic operations

C.C. A digital mixerA digital mixer

D.D. An analog mixerAn analog mixer

Practical Circuits75

G7B07 What are the basic components G7B07 What are the basic components of virtually all oscillators?of virtually all oscillators?

A.A. An amplifier and a dividerAn amplifier and a divider

B.B. A frequency multiplier and a mixerA frequency multiplier and a mixer

C.C. A circulator and a filter operating in a feed-forward A circulator and a filter operating in a feed-forward looploop

D.D. A filter and an amplifier operating in a feedback A filter and an amplifier operating in a feedback looploop

Practical Circuits76

G7B07 What are the basic components G7B07 What are the basic components of virtually all oscillators?of virtually all oscillators?

A.A. An amplifier and a dividerAn amplifier and a divider

B.B. A frequency multiplier and a mixerA frequency multiplier and a mixer

C.C. A circulator and a filter operating in a feed-forward A circulator and a filter operating in a feed-forward looploop

D.D. A filter and an amplifier operating in a A filter and an amplifier operating in a feedback loopfeedback loop

Practical Circuits77

G7B08 What determines the frequency G7B08 What determines the frequency of an RC oscillator?of an RC oscillator?

A.A. The ratio of the capacitors in the feedback loopThe ratio of the capacitors in the feedback loop

B.B. The value of the inductor in the tank circuitThe value of the inductor in the tank circuit

C.C. The phase shift of the RC feedback circuitThe phase shift of the RC feedback circuit

D.D. The gain of the amplifierThe gain of the amplifier

Practical Circuits78

G7B08 What determines the frequency G7B08 What determines the frequency of an RC oscillator?of an RC oscillator?

A.A. The ratio of the capacitors in the feedback loopThe ratio of the capacitors in the feedback loop

B.B. The value of the inductor in the tank circuitThe value of the inductor in the tank circuit

C.C. The phase shift of the RC feedback circuitThe phase shift of the RC feedback circuitD.D. The gain of the amplifierThe gain of the amplifier

Practical Circuits79

G7B09 What determines the frequency G7B09 What determines the frequency of an LC oscillator?of an LC oscillator?

A.A. The number of stages in the counterThe number of stages in the counter

B.B. The number of stages in the dividerThe number of stages in the divider

C.C. The inductance and capacitance in the tank circuitThe inductance and capacitance in the tank circuit

D.D. The time delay of the lag circuitThe time delay of the lag circuit

Practical Circuits80

G7B09 What determines the frequency G7B09 What determines the frequency of an LC oscillator?of an LC oscillator?

A.A. The number of stages in the counterThe number of stages in the counter

B.B. The number of stages in the dividerThe number of stages in the divider

C.C. The inductance and capacitance in the The inductance and capacitance in the tank circuittank circuit

D.D. The time delay of the lag circuitThe time delay of the lag circuit

Practical Circuits81

G7B10 Which of the following is a G7B10 Which of the following is a characteristic of a Class A amplifier?characteristic of a Class A amplifier?

A.A. Low standby powerLow standby power

B.B. High EfficiencyHigh Efficiency

C.C. No need for biasNo need for bias

D.D. Low distortionLow distortion

Practical Circuits82

G7B10 Which of the following is a G7B10 Which of the following is a characteristic of a Class A amplifier?characteristic of a Class A amplifier?

A.A. Low standby powerLow standby power

B.B. High EfficiencyHigh Efficiency

C.C. No need for biasNo need for bias

D.D. Low distortionLow distortion

Practical Circuits83

G7B11 For which of the following G7B11 For which of the following modes is a Class C power stage modes is a Class C power stage appropriate for amplifying a modulated appropriate for amplifying a modulated signal?signal?

A.A. SSBSSB

B.B. CWCW

C.C. AMAM

D.D. All of these answers are correctAll of these answers are correct

Practical Circuits84

G7B11 For which of the following G7B11 For which of the following modes is a Class C power stage modes is a Class C power stage appropriate for amplifying a modulated appropriate for amplifying a modulated signal?signal?

A.A. SSBSSB

B.B. CWCWC.C. AMAM

D.D. All of these answers are correctAll of these answers are correct

Practical Circuits85

G7B12 Which of the following is an G7B12 Which of the following is an advantage of a Class C amplifier?advantage of a Class C amplifier?

A.A. High efficiencyHigh efficiency

B.B. Linear operationLinear operation

C.C. No need for tuned circuitsNo need for tuned circuits

D.D. All of these answers are correctAll of these answers are correct

Practical Circuits86

G7B12 Which of the following is an G7B12 Which of the following is an advantage of a Class C amplifier?advantage of a Class C amplifier?

A.A. High efficiencyHigh efficiencyB.B. Linear operationLinear operation

C.C. No need for tuned circuitsNo need for tuned circuits

D.D. All of these answers are correctAll of these answers are correct

Practical Circuits87

G7B13 How is the efficiency of an RF G7B13 How is the efficiency of an RF power amplifier determined?power amplifier determined?

A.A. Divide the DC input power by the DC output powerDivide the DC input power by the DC output power

B.B. Divide the RF output power by the DC input powerDivide the RF output power by the DC input power

C.C. Multiply the RF input power by the reciprocal of the Multiply the RF input power by the reciprocal of the RF output powerRF output power

D.D. Add the RF input power to the DC output powerAdd the RF input power to the DC output power

Practical Circuits88

G7B13 How is the efficiency of an RF G7B13 How is the efficiency of an RF power amplifier determined?power amplifier determined?

A.A. Divide the DC input power by the DC output powerDivide the DC input power by the DC output power

B.B. Divide the RF output power by the DC Divide the RF output power by the DC input powerinput power

C.C. Multiply the RF input power by the reciprocal of the Multiply the RF input power by the reciprocal of the RF output powerRF output power

D.D. Add the RF input power to the DC output powerAdd the RF input power to the DC output power

Practical Circuits89

G7B14 Which of the following G7B14 Which of the following describes a linear amplifier?describes a linear amplifier?

A.A. Any RF power amplifier used in conjunction with an Any RF power amplifier used in conjunction with an amateur transceiveramateur transceiver

B.B. An amplifier whose output preserves the input An amplifier whose output preserves the input waveformwaveform

C.C. A Class C high efficiency amplifierA Class C high efficiency amplifier

D.D. An amplifier used as a frequency multiplierAn amplifier used as a frequency multiplier

Practical Circuits90

G7B14 Which of the following describes G7B14 Which of the following describes a linear amplifier?a linear amplifier?

A.A. Any RF power amplifier used in conjunction with an Any RF power amplifier used in conjunction with an amateur transceiveramateur transceiver

B.B. An amplifier whose output preserves the An amplifier whose output preserves the input waveforminput waveform

C.C. A Class C high efficiency amplifierA Class C high efficiency amplifier

D.D. An amplifier used as a frequency multiplierAn amplifier used as a frequency multiplier

Practical Circuits91

G7 - PRACTICAL CIRCUITS G7 - PRACTICAL CIRCUITS [2 exam question - 2 groups][2 exam question - 2 groups]