In Figure E6-1, what is the schematic symbol for a PNP transistor?
A. 1
B. 2
C. 4
D. 5
E6A01
In what application is gallium arsenide used as a semiconductor material in preference to germanium or silicon?
A. In high-current rectifier circuits
B. In high-power audio circuits
C. At microwave frequencies
D. At very low frequency RF circuits
E6A02
What type of semiconductor material contains more free electrons than pure germanium or silicon crystals?
A. N-type
B. P-type
C. Bipolar
D. Insulated gate
E6A03
What are the majority charge carriers in P-type semiconductor material?
A. Free neutrons
B. Free protons
C. Holes
D. Free electrons
E6A04
What is the name given to an impurity atom that adds holes to a semiconductor crystal structure?
A. Insulator impurity
B. N-type impurity
C. Acceptor impurity
D. Donor impurity
E6A05
What is the alpha of a bipolar junction transistor?
A. The change of collector current with respect to base current
B. The change of base current with respect to collector current
C. The change of collector current with respect to emitter current
D. The change of collector current with respect to gate current
E6A06
What is meant by the beta of a bipolar junction transistor?
A. The frequency at which the current gain is reduced to 1
B. The change in collector current with respect to base current
C. The breakdown voltage of the base to collector junction
D. The switching speed of the transistor
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E6A07 In Figure E6-1, what is the schematic symbol for a PNP transistor? A. 1 B. 2 C. 4 D. 5
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E6A09
What is a depletion-mode FET?
A. An FET that exhibits a current flow between source and drain when no gate voltage is applied
B. An FET that has no current flow between source and drain when no gate voltage is applied
C. An FET without a channel so no current flows with zero gate voltage
D. An FET without a channel so maximum gate current flows
E6A10 {Was E6A09]
In Figure E6-2, what is the schematic symbol for an N-channel dual-gate MOSFET?
A. 2
B. 4
C. 5
D. 6
E6A11
In Figure E6-2, what is the schematic symbol for a P-channel junction FET?
A. 1
B. 2
C. 3
D. 6
E6A12
Why do many MOSFET devices have built-in gate-protective Zener diodes?
A. To provide a voltage reference for the correct amount of reverse-bias gate voltage
B. To protect the substrate from excessive voltages
C. To keep the gate voltage within specifications and prevent the device from overheating
D. To reduce the chance of the gate insulation being punctured by static discharges or excessive voltages
E6A13
What do the initials CMOS stand for?
A. Common mode oscillating system
B. Complementary mica-oxide silicon
C. Complementary metal-oxide semiconductor
D. Complementary metal-oxide substrate
E6A14
How does DC input impedance at the gate of a field-effect transistor compare with the DC input impedance of a bipolar transistor?
A. They cannot be compared without first knowing the supply voltage
B. An FET has low input impedance; a bipolar transistor has high input impedance
C. An FET has high input impedance; a bipolar transistor has low input impedance
D. The input impedance of FETs and bipolar transistors is the same
E6A15
What two elements widely used in semiconductor devices exhibit both metallic and nonmetallic characteristics?
A. Silicon and gold
B. Silicon and germanium
C. Galena and germanium
D. Galena and bismuth
E6A16
What type of semiconductor material contains fewer free electrons than pure germanium or silicon crystals?
A. N-type
B. P-type
C. Superconductor-type
D. Bipolar-type
E6A17
What are the majority charge carriers in N-type semiconductor material?
A. Holes
B. Free electrons
C. Free protons
D. Free neutrons
E6A18
What are the names of the three terminals of a field-effect transistor?
A. Gate 1, gate 2, drain
B. Emitter, base, collector
C. Emitter, base 1, base 2
D. Gate, drain, source
E6B Semiconductor diodes
E6B01
What is the principal characteristic of a Zener diode?
A. A constant current under conditions of varying voltage
B. A constant voltage under conditions of varying current
C. A negative resistance region
D. An internal capacitance that varies with the applied voltage
E6B02
What is the principal characteristic of a tunnel diode?
A. A high forward resistance
B. A very high PIV
C. A negative resistance region
D. A high forward current rating
E6B03
What is an important characteristic of a Schottky Barrier diode as compared to an ordinary silicon diode when used as a power supply rectifier?
A. Much higher reverse voltage breakdown
B. Controlled reverse avalanche voltage
C. Enhanced carrier retention time
D. Less forward voltage drop
E6B04
What special type of diode is capable of both amplification and oscillation?
A. Point contact
B. Zener
C. Tunnel
D. Junction
E6B05
What type of semiconductor device varies its internal capacitance as the voltage applied to its terminals varies?
A. Varactor diode
B. Tunnel diode
C. Silicon-controlled rectifier
D. Zener diode
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E6B06 In Figure E6-3, what is the schematic symbol for a varactor diode? A. 8 B. 6 C. 2 D. 1
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E6B08
What limits the maximum forward current rating in a junction diode?
A. Peak inverse voltage
B. Junction temperature
C. Forward voltage
D. Back EMF
E6B09
Which of the following describes a type of semiconductor diode?
A. Metal-semiconductor junction
B. Electrolytic rectifier
C. CMOS-field effect
D. Thermionic emission diode
E6B10
What is a common use for point contact diodes?
A. As a constant current source
B. As a constant voltage source
C. As an RF detector
D. As a high voltage rectifier
E6B11
In Figure E6-3, what is the schematic symbol for a light-emitting diode?
A. 1
B. 5
C. 6
D. 7
E6B12
How are junction diodes rated?
A. Maximum forward current and capacitance
B. Maximum reverse current and PIV
C. Maximum reverse current and capacitance
D. Maximum forward current and PIV
E6B13
What is one common use for PIN diodes?
A. As a constant current source
B. As a constant voltage source
C. As an RF switch
D. As a high voltage rectifier
E6B14
What type of bias is required for an LED to produce luminescence?
A. Reverse bias
B. Forward bias
C. Zero bias
D. Inductive bias
E6C Integrated circuits: TTL digital integrated circuits; CMOS digital integrated circuits; gates
E6C01
What is the recommended power supply voltage for TTL series integrated circuits?
A. 12 volts
B. 1.5 volts
C. 5 volts
D. 13.6 volts
E6C02
What logic state do the inputs of a TTL device assume if they are left open?
A. A logic-high state
B. A logic-low state
C. The device becomes randomized and will not provide consistent high or low-logic states
D. Open inputs on a TTL device are ignored
E6C03
What level of input voltage is a logic "high" in a TTL device operating with a positive 5-volt power supply?
A. 2.0 to 5.5 volts
B. 1.5 to 3.0 volts
C. 1.0 to 1.5 volts
D. -5.0 to -2.0 volts
E6C04
What level of input voltage is a logic "low" in a TTL device operating with a positive 5-volt power-supply?
A. -2.0 to -5.5 volts
B. 2.0 to 5.5 volts
C. 0.0 to 0.8 volts
D. -0.8 to 0.4 volts
E6C05
Which of the following is an advantage of CMOS logic devices over TTL devices?
A. Differential output capability
B. Lower distortion
C. Immune to damage from static discharge
D. Lower power consumption
E6C06
Why do CMOS digital integrated circuits have high immunity to noise on the input signal or power supply?
A. Larger bypass capacitors are used in CMOS circuit design
B. The input switching threshold is about two times the power supply voltage
C. The input switching threshold is about one-half the power supply voltage
D. Input signals are stronger
E6C07
In Figure E6-5, what is the schematic symbol for an AND gate?
A. 1
B. 2
C. 3
D. 4
E6C08
In Figure E6-5, what is the schematic symbol for a NAND gate?
A. 1
B. 2
C. 3
D. 4
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E6C09 In Figure E6-5, what is the schematic symbol for an OR gate? A. 2 B. 3 C. 4 D. 6
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E6C10 In Figure E6-5, what is the schematic symbol for a NOR gate? A. 1 B. 2 C. 3 D. 4
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E6C11 In Figure E6-5, what is the schematic symbol for the NOT operation (inverter)? A. 2 B. 4 C. 5 D. 6
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E6D01
How is the electron beam deflected in a vidicon?
A. By varying the beam voltage
B. By varying the bias voltage on the beam forming grids inside the tube
C. By varying the beam current
D. By varying electromagnetic fields
E6D02
What is cathode ray tube (CRT)
persistence?
A. The time it takes for an image to appear after the electron beam is turned on
B. The relative brightness of the display under varying conditions of ambient light
C. The ability of the display to remain in focus under varying conditions
D. The length of time the image remains on the screen after the beam is turned off
E6D03
If a cathode ray tube (CRT)is designed to operate with an anode voltage of 25,000 volts, what will happen if the anode voltage is increased to 35,000 volts?
A. The image size will decrease
B. The image size will increase
C. The image will become larger and brighter
D. There will be no apparent change
E6D04
Exceeding what design rating can cause a cathode ray tube (CRT)
to generate X-rays?
A. The heater voltage
B. The anode voltage
C. The operating temperature
D. The operating frequency
E6D05
Which of the following is true of a charge-coupled device (CCD)?
A. Its phase shift changes rapidly with frequency
B. It is a CMOS analog-to-digital converter
C. It samples an analog signal and passes it in stages from the input to the output
D. It is used in a battery charger circuit
E6D06
What function does a charge-coupled device (CCD) serve in a modern video camera?
A. It stores photogenerated charges as signals corresponding to pixels
B. It generates the horizontal pulses needed for electron beam scanning
C. It focuses the light used to produce a pattern of electrical charges corresponding to the image
D. It combines audio and video information to produce a composite RF signal
E6D07
What is a liquid-crystal display (LCD)?
A. A modern replacement for a quartz crystal oscillator which displays its fundamental frequency
B. A display that uses a crystalline liquid to change the way light is refracted
C. A frequency-determining unit for a transmitter or receiver
D. A display that uses a glowing liquid to remain brightly lit in dim light
E6D08
What material property determines the inductance of a toroidal inductor with a 10-turn winding?
A. Core load current
B. Core resistance
C. Core reactivity
D. Core permeability
E6D09
What is the usable frequency range of inductors that use toroidal cores, assuming a correct selection of core material for the frequency being used?
A. From a few kHz to no more than 30 MHz
B. From less than 20 Hz to approximately 300 MHz
C. From approximately 1000 Hz to no more than 3000 kHz
D. From about 100 kHz to at least 1000 GHz
E6D10
What is one important reason for using powdered-iron toroids rather than ferrite toroids in an inductor?
A. Powdered-iron toroids generally have greater initial permeabilities
B. Powdered-iron toroids generally have better temperature stability
C. Powdered-iron toroids generally require fewer turns to produce a given inductance value
D. Powdered-iron toroids have the highest power handling capacity
E6D11
What devices are commonly used as VHF and UHF parasitic suppressors at the input and output terminals of transistorized HF amplifiers?
A. Electrolytic capacitors
B. Butterworth filters
C. Ferrite beads
D. Steel-core toroids
E6D12
What is a primary advantage of using a toroidal core instead of a solenoidal core in an inductor?
A. Toroidal cores contain most of the magnetic field within the core material
B. Toroidal cores make it easier to couple the magnetic energy into other components
C. Toroidal cores exhibit greater hysteresis
D. Toroidal cores have lower Q characteristics
E6D13
How many turns will be required to produce a 1-mH inductor using a ferrite toroidal core that has an inductance index (A L) value of 523 millihenrys/1000 turns?
A. 2 turns
B. 4 turns
C. 43 turns
D. 229 turns
E6D14
How many turns will be required to produce a 5-microhenry inductor using a powdered-iron toroidal core that has an inductance index (A L)
value of 40 microhenrys/100 turns?
A. 35 turns
B. 13 turns
C. 79 turns
D. 141 turns
E6D15
What type of CRT deflection is better when high-frequency waves are to be displayed on the screen?
A. Electromagnetic
B. Tubular
C. Radar
D. Electrostatic
E6D16
Which is NOT true of a charge-coupled device (CCD)?
A. It uses a combination of analog and digital circuitry
B. It can be used to make an audio delay line
C. It is commonly used as an analog-to-digital converter
D. It samples and stores analog signals
E6D17
What is the principle advantage of liquid-crystal display (LCD) devices over other types of display devices?
A. They consume less power
B. They can display changes instantly
C. They are visible in all light conditions
D. They can be easily interchanged with other display devices
E6D18
What is one reason for using ferrite toroids rather than powdered-iron toroids in an inductor?
A. Ferrite toroids generally have lower initial permeabilities
B. Ferrite toroids generally have better temperature stability
C. Ferrite toroids generally require fewer turns to produce a given inductance value
D. Ferrite toroids are easier to use with surface mount technology
E6E Piezoelectric crystals and MMICS: quartz crystals (as used in oscillators and filters)
; monolithic amplifiers (MMICs)
E6E01
Which of these filter bandwidths would be a good choice for use in a SSB radiotelephone transmitter?
A. 6 kHz at -6 dB
B. 2.4 kHz at -6 dB
C. 500 Hz at -6 dB
D. 15 kHz at -6 dB
E6E02
Which of these filter bandwidths would be a good choice for use with standard double-sideband AM transmissions?
A. 1 kHz at -6 dB
B. 500 Hz at -6 dB
C. 6 kHz at -6 dB
D. 15 kHz at -6 dB
E6E03
What is a crystal lattice filter?
A. A power supply filter made with interlaced quartz crystals
B. An audio filter made with four quartz crystals that resonate at 1-kHz intervals
C. A filter with wide bandwidth and shallow skirts made using quartz crystals
D. A filter with narrow bandwidth and steep skirts made using quartz crystals
E6E04
What technique is used to construct low-cost, high-performance crystal ladder filters?
A. Obtain a small quantity of custom-made crystals
B. Choose a crystal with the desired bandwidth and operating frequency to match a desired center frequency
C. Measure crystal bandwidth to ensure at least 20% coupling
D. Measure crystal frequencies and carefully select units with a frequency variation of less than 10% of the desired filter bandwidth
E6E05
Which of the following factors has the greatest effect in helping determine the bandwidth and response shape of a crystal ladder filter?
A. The relative frequencies of the individual crystals
B. The DC voltage applied to the quartz crystal
C. The gain of the RF stage preceding the filter
D. The amplitude of the signals passing through the filter
E6E06
What is one aspect of the piezoelectric effect?
A. Physical deformation of a crystal by the application of a voltage
B. Mechanical deformation of a crystal by the application of a magnetic field
C. The generation of electrical energy by the application of light
D. Reversed conduction states when a P-N junction is exposed to light
E6E07
What is the characteristic impedance of circuits in which almost all MMICs are designed to work?
A. 50 ohms
B. 300 ohms
C. 450 ohms
D. 10 ohms
E6E08
What is the typical noise figure of a monolithic microwave integrated circuit (MMIC)amplifier?
A. Less than 1 dB
B. Approximately 3.5 to 6 dB
C. Approximately 8 to 10 dB
D. More than 20 dB
E6E09
What type of amplifier device consists of a small pill-type package with an input lead, an output lead and 2 ground leads?
A. A junction field-effect transistor (JFET)
B. An operational amplifier integrated circuit (OAIC)
C. An indium arsenide integrated circuit (IAIC)
D. A monolithic microwave integrated circuit (MMIC)
E6E10
What typical construction technique is used when building an amplifier for the microwave bands containing a monolithic microwave integrated circuit (MMIC)?
A. Ground-plane "ugly" construction
B. Microstrip construction
C. Point-to-point construction
D. Wave-soldering construction
E6E11
How is the operating bias voltage normally supplied to the most common type of monolithic microwave integrated circuit (MMIC)?
A. Through a resistor and/or RF choke connected to the amplifier output lead
B. MMICs require no operating bias
C. Through a capacitor and RF choke connected to the amplifier input lead
D. Directly to the bias-voltage (VCC IN)
lead
E6E12
What supply voltage do monolithic microwave integrated circuits (MMIC)
amplifiers typically require?
A. 1 volt DC
B. 12 volts DC
C. 20 volts DC
D. 120 volts DC
E6E13
What is the most common package for inexpensive monolithic microwave integrated circuit (MMIC) amplifiers?
A. Beryllium oxide packages
B. Glass packages
C. Plastic packages
D. Ceramic packages
E6F Optical components and power systems: photoconductive principles and effects, photovoltaic systems, optical couplers, optical sensors, and optoisolators
E6F01
What is photoconductivity?
A. The conversion of photon energy to electromotive energy
B. The increased conductivity of an illuminated semiconductor
C. The conversion of electromotive energy to photon energy
D. The decreased conductivity of an illuminated semiconductor
E6F02
What happens to the conductivity of a photoconductive material when light shines on it?
A. It increases
B. It decreases
C. It stays the same
D. It becomes unstable
E6F03
What is the most common configuration for an optocoupler?
A. A lens and a photomultiplier
B. A frequency modulated helium-neon laser
C. An amplitude modulated helium-neon laser
D. An LED and a phototransistor
E6F04
Which of the following is an optoisolator?
A. An LED and a phototransistor
B. A P-N junction that develops an excess positive charge when exposed to light
C. An LED and a capacitor
D. A P-N junction that develops an excess negative charge when exposed to light
E6F05
What is an optical shaft encoder?
A. An array of neon or LED indicators whose light transmission path is controlled by a rotating wheel
B. An array of optocouplers whose light transmission path is controlled by a rotating wheel
C. An array of neon or LED indicators mounted on a rotating wheel in a coded pattern
D. An array of optocouplers mounted on a rotating wheel in a coded pattern
E6F06
What characteristic of a crystalline solid will photoconductivity change?
A. The capacitance
B. The inductance
C. The specific gravity
D. The resistance
E6F07
Which material will exhibit the greatest photoconductive effect when illuminated by visible light?
A. Potassium nitrate
B. Lead sulfide
C. Cadmium sulfide
D. Sodium chloride
E6F08
Which material will exhibit the greatest photoconductive effect when illuminated by infrared light?
A. Potassium nitrate
B. Lead sulfide
C. Cadmium sulfide
D. Sodium chloride
E6F09
Which of the following materials is affected the most by photoconductivity?
A. A crystalline semiconductor
B. An ordinary metal
C. A heavy metal
D. A liquid semiconductor
E6F10
What characteristic of optoisolators is often used in power supplies?
A. They have low impedance between the light source and the phototransistor
B. They have very high impedance between the light source and the phototransistor
C. They have low impedance between the light source and the LED
D. They have very high impedance between the light source and the LED
E6F11
What characteristic of optoisolators makes them suitable for use with a triac to form the solid-state equivalent of a mechanical relay for a 120 V AC household circuit?
A. Optoisolators provide a low impedance link between a control circuit and a power circuit
B. Optoisolators provide impedance matching between the control circuit and power circuit
C. Optoisolators provide a very high degree of electrical isolation between a control circuit and a power circuit
D. Optoisolators eliminate (isolate)
the effects of reflected light in the control circuit
E6F12
Which of the following types of photovoltaic cell has the highest efficiency?
A. Silicon
B. Silver iodide
C. Selenium
D. Gallium arsenide
E6F13
What is the most common type of photovoltaic cell used for electrical power generation?
A. Selenium
B. Silicon
C. Cadmium Sulfide
D. Copper oxide
E6F14
Which of the following is the approximate open-circuit voltage produced by a fully-illuminated silicon photovoltaic cell?
A. 0.1 V
B. 0.5 V
C. 1.5 V
D. 12 V
E6F15
What absorbs the energy from light falling on a photovoltaic cell?
A. Protons
B. Photons
C. Electrons
D. Holes