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effective 7/01/2016 thru 6/29/2020

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Topic 2016-E6: Circuit Components


2016-E6A: Semiconductor materials and devices: semiconductor materials; germanium, silicon, P-type, N-type; transistor types: NPN, PNP, junction, field-effect transistors: enhancement mode; depletion mode; MOS; CMOS; N-channel; P-channel

2016-E6A01: In what application is gallium arsenide used as a semiconductor material in preference to germanium or silicon?

In microwave circuits

In high-current rectifier circuits

In high-power audio circuits

In very low frequency RF circuits



2016-E6A02: Which of the following semiconductor materials contains excess free electrons?

N-type

P-type

Bipolar

Insulated gate



2016-E6A03: Why does a PN-junction diode not conduct current when reverse biased?

Holes in P-type material and electrons in the N-type material are separated by the applied voltage, widening the depletion region

Only P-type semiconductor material can conduct current

Only N-type semiconductor material can conduct current

Excess holes in P-type material combine with the electrons in N-type material, converting the entire diode into an insulator



2016-E6A04: What is the name given to an impurity atom that adds holes to a semiconductor crystal structure?

Acceptor impurity

Insulator impurity

N-type impurity

Donor impurity



2016-E6A05: What is the alpha of a bipolar junction transistor?

The change of collector current with respect to emitter current

The change of collector current with respect to base current

The change of base current with respect to collector current

The change of collector current with respect to gate current



2016-E6A06: What is the beta of a bipolar junction transistor?

The change in collector current with respect to base current

The frequency at which the current gain is reduced to 1

The breakdown voltage of the base to collector junction

The switching speed of the transistor



2016-E6A07: Which of the following indicates that a silicon NPN junction transistor is biased on?

Base-to-emitter voltage of approximately 0.6 to 0.7 volts

Base-to-emitter resistance of approximately 6 to 7 ohms

Base-to-emitter resistance of approximately 0.6 to 0.7 ohms

Base-to-emitter voltage of approximately 6 to 7 volts



2016-E6A08: What term indicates the frequency at which the grounded-base current gain of a transistor has decreased to 0.7 of the gain obtainable at 1 kHz?

Alpha cutoff frequency

Corner frequency

Alpha rejection frequency

Beta cutoff frequency



2016-E6A09: What is a depletion-mode FET?

An FET that exhibits a current flow between source and drain when no gate voltage is applied

An FET that has no current flow between source and drain when no gate voltage is applied

Any FET without a channel

Any FET for which holes are the majority carriers



2016-E6A10: In Figure E6-2, what is the schematic symbol for an N-channel dual-gate MOSFET?

4

2

5

6



2016-E6A11: In Figure E6-2, what is the schematic symbol for a P-channel junction FET?

1

2

3

6



2016-E6A12: Why do many MOSFET devices have internally connected Zener diodes on the gates?

To reduce the chance of the gate insulation being punctured by static discharges or excessive voltages

To provide a voltage reference for the correct amount of reverse-bias gate voltage

To protect the substrate from excessive voltages

To keep the gate voltage within specifications and prevent the device from overheating



2016-E6A13: What do the initials CMOS stand for?

Complementary Metal-Oxide Semiconductor

Common Mode Oscillating System

Complementary Mica-Oxide Silicon

Common Mode Organic Silicon



2016-E6A14: How does DC input impedance at the gate of a field-effect transistor compare with the DC input impedance of a bipolar transistor?

An FET has high input impedance; a bipolar transistor has low input impedance

They are both low impedance

An FET has low input impedance; a bipolar transistor has high input impedance

They are both high impedance



2016-E6A15: Which semiconductor material contains excess holes in the outer shell of electrons?

P-type

N-type

Superconductor-type

Bipolar-type



2016-E6A16: What are the majority charge carriers in N-type semiconductor material?

Free electrons

Holes

Free protons

Free neutrons



2016-E6A17: What are the names of the three terminals of a field-effect transistor?

Gate, drain, source

Gate 1, gate 2, drain

Emitter, base, collector

Emitter, base 1, base 2






2016-E6B: Diodes

2016-E6B01: What is the most useful characteristic of a Zener diode?

A constant voltage drop under conditions of varying current

A constant current drop under conditions of varying voltage

A negative resistance region

An internal capacitance that varies with the applied voltage



2016-E6B02: What is an important characteristic of a Schottky diode as compared to an ordinary silicon diode when used as a power supply rectifier?

Less forward voltage drop

Much higher reverse voltage breakdown

Controlled reverse avalanche voltage

Enhanced carrier retention time



2016-E6B03: What special type of diode is capable of both amplification and oscillation?

Tunnel

Point contact

Zener

Junction



2016-E6B04: What type of semiconductor device is designed for use as a voltage-controlled capacitor?

Varactor diode

Tunnel diode

Silicon-controlled rectifier

Zener diode



2016-E6B05: What characteristic of a PIN diode makes it useful as an RF switch or attenuator?

A large region of intrinsic material

Extremely high reverse breakdown voltage

Ability to dissipate large amounts of power

Reverse bias controls its forward voltage drop



2016-E6B06: Which of the following is a common use of a hot-carrier diode?

As a VHF/UHF mixer or detector

As balanced mixers in FM generation

As a variable capacitance in an automatic frequency control circuit

As a constant voltage reference in a power supply



2016-E6B07: What is the failure mechanism when a junction diode fails due to excessive current?

Excessive junction temperature

Excessive inverse voltage

Insufficient forward voltage

Charge carrier depletion



2016-E6B08: Which of the following describes a type of semiconductor diode?

Metal-semiconductor junction

Electrolytic rectifier

CMOS-field effect

Thermionic emission diode



2016-E6B09: What is a common use for point contact diodes?

As an RF detector

As a constant current source

As a constant voltage source

As a high voltage rectifier



2016-E6B10: In Figure E6-3, what is the schematic symbol for a light-emitting diode?

5

1

6

7



2016-E6B11: What is used to control the attenuation of RF signals by a PIN diode?

Forward DC bias current

A sub-harmonic pump signal

Reverse voltage larger than the RF signal

Capacitance of an RF coupling capacitor



2016-E6B12: What is one common use for PIN diodes?

As an RF switch

As a constant current source

As a constant voltage source

As a high voltage rectifier



2016-E6B13: What type of bias is required for an LED to emit light?

Forward bias

Reverse bias

Zero bias

Inductive bias






2016-E6C: Digital ICs: Families of digital ICs; gates; Programmable Logic Devices (PLDs)

2016-E6C01: What is the function of hysteresis in a comparator?

To prevent input noise from causing unstable output signals

To allow the comparator to be used with AC input signal

To cause the output to change states continually

To increase the sensitivity



2016-E6C02: What happens when the level of a comparator's input signal crosses the threshold?

The comparator changes its output state

The IC input can be damaged

The comparator enters latch-up

The feedback loop becomes unstable



2016-E6C03: What is tri-state logic?

Logic devices with 0, 1, and high impedance output states

Logic devices that utilize ternary math

Low power logic devices designed to operate at 3 volts

Proprietary logic devices manufactured by Tri-State Devices



2016-E6C04: What is the primary advantage of tri-state logic?

Ability to connect many device outputs to a common bus

Low power consumption

High speed operation

More efficient arithmetic operations



2016-E6C05: What is an advantage of CMOS logic devices over TTL devices?

Lower power consumption

Differential output capability

Lower distortion

Immune to damage from static discharge



2016-E6C06: Why do CMOS digital integrated circuits have high immunity to noise on the input signal or power supply?

The input switching threshold is about one-half the power supply voltage

Larger bypass capacitors are used in CMOS circuit design

The input switching threshold is about two times the power supply voltage

Input signals are stronger



2016-E6C07: What best describes a pull-up or pull-down resistor?

A resistor connected to the positive or negative supply line used to establish a voltage when an input or output is an open circuit

A resistor in a keying circuit used to reduce key clicks

A resistor that insures that an oscillator frequency does not drive lower over time

A resistor connected to an op-amp output that only functions when the logic output is false



2016-E6C08: In Figure E6-5, what is the schematic symbol for a NAND gate?

2

1

3

4



2016-E6C09: What is a Programmable Logic Device (PLD)?

A programmable collection of logic gates and circuits in a single integrated circuit

A device to control industrial equipment

Programmable equipment used for testing digital logic integrated circuits

An algorithm for simulating logic functions during circuit design



2016-E6C10: In Figure E6-5, what is the schematic symbol for a NOR gate?

4

1

2

3



2016-E6C11: In Figure E6-5, what is the schematic symbol for the NOT operation (inverter)?

5

2

4

6



2016-E6C12: What is BiCMOS logic?

An integrated circuit logic family using both bipolar and CMOS transistors

A logic device with two CMOS circuits per package

A FET logic family based on bimetallic semiconductors

A logic family based on bismuth CMOS devices



2016-E6C13: Which of the following is an advantage of BiCMOS logic?

It has the high input impedance of CMOS and the low output impedance of bipolar transistors

Its simplicity results in much less expensive devices than standard CMOS

It is totally immune to electrostatic damage

All of these choices are correct



2016-E6C14: What is the primary advantage of using a Programmable Gate Array (PGA) in a logic circuit?

Complex logic functions can be created in a single integrated circuit

Many similar gates are less expensive than a mixture of gate types

A PGA contains its own internal power supply

All of these choices are correct






2016-E6D: Toroidal and Solenoidal Inductors: permeability, core material, selecting, winding; transformers; Piezoelectric devices

2016-E6D01: 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?

35 turns

13 turns

79 turns

141 turns



2016-E6D02: What is the equivalent circuit of a quartz crystal?

Motional capacitance, motional inductance, and loss resistance in series, all in parallel with a shunt capacitor representing electrode and stray capacitance

Motional capacitance, motional inductance, loss resistance, and a capacitor representing electrode and stray capacitance all in parallel

Motional capacitance, motional inductance, loss resistance, and a capacitor representing electrode and stray capacitance all in series

Motional inductance and loss resistance in series, paralleled with motional capacitance and a capacitor representing electrode and stray capacitance



2016-E6D03: Which of the following is an aspect of the piezoelectric effect?

Mechanical deformation of material by the application of a voltage

Mechanical deformation of material by the application of a magnetic field

Generation of electrical energy in the presence of light

Increased conductivity in the presence of light



2016-E6D04: Which materials are commonly used as a slug core in a variable inductor?

Ferrite and brass

Polystyrene and polyethylene

Teflon and Delrin

Cobalt and aluminum



2016-E6D05: What is one reason for using ferrite cores rather than powdered-iron in an inductor?

Ferrite toroids generally require fewer turns to produce a given inductance value

Ferrite toroids generally have lower initial permeability

Ferrite toroids generally have better temperature stability

Ferrite toroids are easier to use with surface mount technology



2016-E6D06: What core material property determines the inductance of a toroidal inductor?

Permeability

Thermal impedance

Resistance

Reactivity



2016-E6D07: What is the usable frequency range of inductors that use toroidal cores, assuming a correct selection of core material for the frequency being used?

From less than 20 Hz to approximately 300 MHz

From a few kHz to no more than 30 MHz

From approximately 10 Hz to no more than 3000 kHz

From about 100 kHz to at least 1000 GHz



2016-E6D08: What is one reason for using powdered-iron cores rather than ferrite cores in an inductor?

Powdered-iron cores generally maintain their characteristics at higher currents

Powdered-iron cores generally have greater initial permeability

Powdered-iron cores generally require fewer turns to produce a given inductance

Powdered-iron cores use smaller diameter wire for the same inductance



2016-E6D09: What devices are commonly used as VHF and UHF parasitic suppressors at the input and output terminals of a transistor HF amplifier?

Ferrite beads

Electrolytic capacitors

Butterworth filters

Steel-core toroids



2016-E6D10: What is a primary advantage of using a toroidal core instead of a solenoidal core in an inductor?

Toroidal cores confine most of the magnetic field within the core material

Toroidal cores make it easier to couple the magnetic energy into other components

Toroidal cores exhibit greater hysteresis

Toroidal cores have lower Q characteristics



2016-E6D11: How many turns will be required to produce a 1-mH inductor using a core that has an inductance index (A L) value of 523 millihenrys/1000 turns?

43 turns

2 turns

4 turns

229 turns



2016-E6D12: What is the definition of saturation in a ferrite core inductor?

The ability of the inductor's core to store magnetic energy has been exceeded

The inductor windings are over coupled

The inductor's voltage rating is exceeded causing a flashover

Adjacent inductors become over-coupled



2016-E6D13: What is the primary cause of inductor self-resonance?

Inter-turn capacitance

The skin effect

Inductive kickback

Non-linear core hysteresis



2016-E6D14: Which type of slug material decreases inductance when inserted into a coil?

Brass

Ceramic

Ferrite

Powdered-iron



2016-E6D15: What is current in the primary winding of a transformer called if no load is attached to the secondary?

Magnetizing current

Direct current

Excitation current

Stabilizing current



2016-E6D16: What is the common name for a capacitor connected across a transformer secondary that is used to absorb transient voltage spikes?

Snubber capacitor

Clipper capacitor

Trimmer capacitor

Feedback capacitor



2016-E6D17: Why should core saturation of a conventional impedance matching transformer be avoided?

Harmonics and distortion could result

Magnetic flux would increase with frequency

RF susceptance would increase

Temporary changes of the core permeability could result






2016-E6E: Analog ICs: MMICs, CCDs, Device packages

2016-E6E01: Which of the following is true of a charge-coupled device (CCD)?

It samples an analog signal and passes it in stages from the input to the output

Its phase shift changes rapidly with frequency

It is a CMOS analog-to-digital converter

It is used in a battery charger circuit



2016-E6E02: Which of the following device packages is a through-hole type?

DIP

PLCC

Ball grid array

SOT



2016-E6E03: Which of the following materials is likely to provide the highest frequency of operation when used in MMICs?

Gallium nitride

Silicon

Silicon nitride

Silicon dioxide



2016-E6E04: Which is the most common input and output impedance of circuits that use MMICs?

50 ohms

300 ohms

450 ohms

10 ohms



2016-E6E05: Which of the following noise figure values is typical of a low-noise UHF preamplifier?

2 dB

-10 dB

44 dBm

-20 dBm



2016-E6E06: What characteristics of the MMIC make it a popular choice for VHF through microwave circuits?

Controlled gain, low noise figure, and constant input and output impedance over the specified frequency range

The ability to retrieve information from a single signal even in the presence of other strong signals

Plate current that is controlled by a control grid

Nearly infinite gain, very high input impedance, and very low output impedance



2016-E6E07: Which of the following is typically used to construct a MMIC-based microwave amplifier?

Microstrip construction

Ground-plane construction

Point-to-point construction

Wave-soldering construction



2016-E6E08: How is voltage from a power supply normally furnished to the most common type of monolithic microwave integrated circuit (MMIC)?

Through a resistor and/or RF choke connected to the amplifier output lead

MMICs require no operating bias

Through a capacitor and RF choke connected to the amplifier input lead

Directly to the bias voltage (VCC IN) lead



2016-E6E09: Which of the following component package types would be most suitable for use at frequencies above the HF range?

Surface mount

TO-220

Axial lead

Radial lead



2016-E6E10: What is the packaging technique in which leadless components are soldered directly to circuit boards?

Surface mount

Direct soldering

Virtual lead mounting

Stripped lead



2016-E6E11: What is a characteristic of DIP packaging used for integrated circuits?

A total of two rows of connecting pins placed on opposite sides of the package (Dual In-line Package)

Package mounts in a direct inverted position

Low leakage doubly insulated package

Two chips in each package (Dual In Package)



2016-E6E12: Why are high-power RF amplifier ICs and transistors sometimes mounted in ceramic packages?

Better dissipation of heat

High-voltage insulating ability

Enhanced sensitivity to light

To provide a low-pass frequency response






2016-E6F: Optical components: photoconductive principles and effects, photovoltaic systems, optical couplers, optical sensors, and optoisolators; LCDs

2016-E6F01: What is photoconductivity?

The increased conductivity of an illuminated semiconductor

The conversion of photon energy to electromotive energy

The conversion of electromotive energy to photon energy

The decreased conductivity of an illuminated semiconductor



2016-E6F02: What happens to the conductivity of a photoconductive material when light shines on it?

It increases

It decreases

It stays the same

It becomes unstable



2016-E6F03: What is the most common configuration of an optoisolator or optocoupler?

An LED and a phototransistor

A lens and a photomultiplier

A frequency modulated helium-neon laser

An amplitude modulated helium-neon laser



2016-E6F04: What is the photovoltaic effect?

The conversion of light to electrical energy

The conversion of voltage to current when exposed to light

The conversion of electrical energy to mechanical energy

The tendency of a battery to discharge when used outside



2016-E6F05: Which describes an optical shaft encoder?

A device which detects rotation of a control by interrupting a light source with a patterned wheel

A device which measures the strength of a beam of light using analog to digital conversion

A digital encryption device often used to encrypt spacecraft control signals

A device for generating RTTY signals by means of a rotating light source



2016-E6F06: Which of these materials is affected the most by photoconductivity?

A crystalline semiconductor

An ordinary metal

A heavy metal

A liquid semiconductor



2016-E6F07: What is a solid state relay?

A device that uses semiconductors to implement the functions of an electromechanical relay

A relay using transistors to drive the relay coil

A mechanical relay that latches in the on or off state each time it is pulsed

A passive delay line



2016-E6F08: Why are optoisolators often used in conjunction with solid state circuits when switching 120VAC?

Optoisolators provide a very high degree of electrical isolation between a control circuit and the circuit being switched

Optoisolators provide a low impedance link between a control circuit and a power circuit

Optoisolators provide impedance matching between the control circuit and power circuit

Optoisolators eliminate the effects of reflected light in the control circuit



2016-E6F09: What is the efficiency of a photovoltaic cell?

The relative fraction of light that is converted to current

The output RF power divided by the input DC power

The effective payback period

The open-circuit voltage divided by the short-circuit current under full illumination



2016-E6F10: What is the most common type of photovoltaic cell used for electrical power generation?

Silicon

Selenium

Cadmium Sulfide

Copper oxide



2016-E6F11: What is the approximate open-circuit voltage produced by a fully-illuminated silicon photovoltaic cell?

0.5 V

0.1 V

1.5 V

12 V



2016-E6F12: What absorbs the energy from light falling on a photovoltaic cell?

Electrons

Protons

Photons

Holes



2016-E6F13: What is a liquid crystal display (LCD)?

A display utilizing a crystalline liquid and polarizing filters which becomes opaque when voltage is applied

A modern replacement for a quartz crystal oscillator which displays its fundamental frequency

A frequency-determining unit for a transmitter or receiver

A display that uses a glowing liquid to remain brightly lit in dim light



2016-E6F14: Which of the following is true of LCD displays?

They may be hard view through polarized lenses

They are hard to view in high ambient light conditions

They only display alphanumeric symbols

All of these choices are correct





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