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
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
Which of the following semiconductor materials contains excess free electrons?
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
What is the name given to an impurity atom that adds holes to a semiconductor crystal structure?
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
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
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
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
Alpha rejection frequency
Beta cutoff frequency
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
In Figure E6-2, what is the schematic symbol for an N-channel dual-gate MOSFET?
In Figure E6-2, what is the schematic symbol for a P-channel junction FET?
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
What do the initials CMOS stand for?
Complementary Metal-Oxide Semiconductor
Common Mode Oscillating System
Complementary Mica-Oxide Silicon
Common Mode Organic Silicon
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
Which semiconductor material contains excess holes in the outer shell of electrons?
What are the majority charge carriers in N-type semiconductor material?
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
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
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
What special type of diode is capable of both amplification and oscillation?
What type of semiconductor device is designed for use as a voltage-controlled capacitor?
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
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
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
Which of the following describes a type of semiconductor diode?
Thermionic emission diode
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
In Figure E6-3, what is the schematic symbol for a light-emitting diode?
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
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
What type of bias is required for an LED to emit light?
2016-E6C: Digital ICs: Families of digital ICs; gates; Programmable Logic Devices (PLDs)
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
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
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
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
What is an advantage of CMOS logic devices over TTL devices?
Lower power consumption
Differential output capability
Immune to damage from static discharge
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
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
In Figure E6-5, what is the schematic symbol for a NAND gate?
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
In Figure E6-5, what is the schematic symbol for a NOR gate?
In Figure E6-5, what is the schematic symbol for the NOT operation (inverter)?
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
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
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
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?
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
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
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
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
What core material property determines the inductance of a toroidal inductor?
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
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
What devices are commonly used as VHF and UHF parasitic suppressors at the input and output terminals of a transistor HF amplifier?
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
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?
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
What is the primary cause of inductor self-resonance?
The skin effect
Non-linear core hysteresis
Which type of slug material decreases inductance when inserted into a coil?
What is current in the primary winding of a transformer called if no load is attached to the secondary?
What is the common name for a capacitor connected across a transformer secondary that is used to absorb transient voltage spikes?
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
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
Which of the following device packages is a through-hole type?
Ball grid array
Which of the following materials is likely to provide the highest frequency of operation when used in MMICs?
Which is the most common input and output impedance of circuits that use MMICs?
Which of the following noise figure values is typical of a low-noise UHF preamplifier?
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
Which of the following is typically used to construct a MMIC-based microwave amplifier?
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
Which of the following component package types would be most suitable for use at frequencies above the HF range?
What is the packaging technique in which leadless components are soldered directly to circuit boards?
Virtual lead mounting
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)
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
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
What happens to the conductivity of a photoconductive material when light shines on it?
It stays the same
It becomes unstable
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
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
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
Which of these materials is affected the most by photoconductivity?
A crystalline semiconductor
An ordinary metal
A heavy metal
A liquid semiconductor
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
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
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
What is the most common type of photovoltaic cell used for electrical power generation?
What is the approximate open-circuit voltage produced by a fully-illuminated silicon photovoltaic cell?
What absorbs the energy from light falling on a photovoltaic cell?
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
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
● = Unseen
● = Weak
● = Review
● = Learned
● = Incorrect answer