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Amateur Radio Question PoolsNew! View the differences between the 2008 Extra question pool and the previous pool. Amateur Extra Class Question PoolPrev 1 2 3 4 5 6 7 8 9 0 NextE6A01 In what application is gallium arsenide used as a semiconductor material in preference to germanium or silicon? In high-current rectifier circuits In high-power audio circuits At microwave-frequency frequencies At very low frequency RF circuits E6A02 What type of semiconductor material contains more free electrons than pure germanium or silicon crystals? N-type P-type Bipolar Insulated gate E6A03 What are the majority charge carriers in P-type semiconductor material? Free neutrons Free protons Holes Free electrons E6A04 What is the name given to an impurity atom that adds holes to a semiconductor crystal structure? Insulator impurity N-type impurity Acceptor impurity Donor impurity E6A05 What is the alpha of a bipolar transistor? 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 emitter current The change of collector current with respect to gate current E6A06 In Figure E6-1, what is the schematic symbol for a PNP transistor? 1 2 4 5 E6A07 What term indicates the frequency at which a transistor grounded base current gain has decreased to 0.7 of the gain obtainable at 1 kHz? Corner frequency Alpha rejection frequency Beta cutoff frequency Alpha cutoff frequency E6A08 What is a depletion-mode FET? An FET that has a channel with no gate voltage applied; a current flows with zero gate voltage An FET that has a channel that blocks current when the gate voltage is zero An FET without a channel; no current flows with zero gate voltage An FET without a channel to hinder current through the gate E6A09 In Figure E6-2, what is the schematic symbol for an N-channel dual-gate MOSFET? 2 4 5 6 E6A10 In Figure E6-2, what is the schematic symbol for a P-channel junction FET? 1 2 3 6 E6A11 Why do many MOSFET devices have built-in gate-protective Zener diodes? 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 To prevent the gate insulation from being punctured by small static charges or excessive voltages E6A12 What do the initials CMOS stand for? Common mode oscillating system Complementary mica-oxide silicon Complementary metal-oxide semiconductor Complementary metal-oxide substrate E6A13 How does DC input impedance on the gate of a field-effect transistor compare with the DC input impedance of a bipolar transistor? They cannot be compared without first knowing the supply voltage An FET has low input impedance; a bipolar transistor has high input impedance An FET has high input impedance; a bipolar transistor has low input impedance The input impedance of FETs and bipolar transistors is the same E6A14 What two elements widely used in semiconductor devices exhibit both metallic and nonmetallic characteristics? Silicon and gold Silicon and germanium Galena and germanium Galena and bismuth E6A15 What type of semiconductor material contains fewer free electrons than pure germanium or silicon crystals? N-type P-type Superconductor-type Bipolar-type E6A16 What are the majority charge carriers in N-type semiconductor material? Holes Free electrons Free protons Free neutrons E6A17 What are the three terminals of a field-effect transistor? Gate 1, gate 2, drain Emitter, base, collector Emitter, base 1, base 2 Gate, drain, source E6B01 What is the principal characteristic of a Zener diode? A constant current under conditions of varying voltage A constant voltage under conditions of varying current A negative resistance region An internal capacitance that varies with the applied voltage E6B02 What is the principal characteristic of a tunnel diode? A high forward resistance A very high PIV A negative resistance region A high forward current rating E6B03 What special type of diode is capable of both amplification and oscillation? Point contact Zener Tunnel Junction E6B04 What type of semiconductor diode varies its internal capacitance as the voltage applied to its terminals varies? Varactor Tunnel Silicon-controlled rectifier Zener E6B05 In Figure E6-3, what is the schematic symbol for a varactor diode? 8 6 2 1 E6B06 What is a common use of a hot-carrier diode? 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 As VHF and UHF mixers and detectors E6B07 What limits the maximum forward current rating in a junction diode? Peak inverse voltage Junction temperature Forward voltage Back EMF E6B08 Structurally, what are the two main categories of semiconductor diodes? PN junction and metal-semiconductor junction Electrolytic and PN junction CMOS-field effect and metal-semiconductor junction Vacuum and point contact E6B09 What is a common use for point contact diodes? As a constant current source As a constant voltage source As an RF detector As a high voltage rectifier E6B10 In Figure E6-3, what is the schematic symbol for a light-emitting diode? 1 5 6 7 E6B11 What voltage gain can be expected from the circuit in Figure E6-4 when R1 is 10 ohms and RF is 470 ohms? 0.21 94 47 24 E6B12 How does the gain of a theoretically ideal operational amplifier vary with frequency? It increases linearly with increasing frequency It decreases linearly with increasing frequency It decreases logarithmically with increasing frequency It does not vary with frequency E6B13 What essentially determines the output impedance of a FET common-source amplifier? The drain resistor The input impedance of the FET The drain supply voltage The gate supply voltage E6B14 What will be the voltage of the circuit shown in Figure E6-4 if R1 is 1000 ohms and RF is 10,000 ohms and 0.23 volts is applied to the input? 0.23 volts 2.3 volts -0.23 volts -2.3 volts E6B15 What voltage gain can be expected from the circuit in Figure E6-4 when R1 is 1800 ohms and RF is 68 kilohms? 1 0.03 38 76 E6B16 What voltage gain can be expected from the circuit in Figure E6-4 when R1 is 3300 ohms and RF is 47 kilohms? 28 14 7 0.07 E6B18 Which of the following circuits is used to recover audio from an FM voice signal? A doubly balanced mixer A phase-locked loop A differential voltage amplifier A variable frequency oscillator E6B19 What is the capture range of a phase-locked loop circuit? The frequency range over which the circuit can lock The voltage range over which the circuit can lock The input impedance range over which the circuit can lock The range of time it takes the circuit to lock E6B20 How are junction diodes rated? Maximum forward current and capacitance Maximum reverse current and PIV Maximum reverse current and capacitance Maximum forward current and PIV E6B21 What is one common use for PIN diodes? As a constant current source As a constant voltage source As an RF switch As a high voltage rectifier E6B22 What type of bias is required for an LED to produce luminescence? Reverse bias Forward bias Zero bias Inductive bias E6B23 What is an operational amplifier? A high-gain, direct-coupled differential amplifier whose characteristics are determined by components external to the amplifier A high-gain, direct-coupled audio amplifier whose characteristics are determined by components external to the amplifier An amplifier used to increase the average output of frequency modulated amateur signals to the legal limit A program subroutine that calculates the gain of an RF amplifier E6B24 What is meant by the term op-amp input-offset voltage? The output voltage of the op-amp minus its input voltage The difference between the output voltage of the op-amp and the input voltage required in the following stage The potential between the amplifier input terminals of the op-amp in a closed-loop condition The potential between the amplifier input terminals of the op-amp in an open-loop condition E6B25 What is the input impedance of a theoretically ideal op-amp? 100 ohms 1000 ohms Very low Very high E6B26 What is the output impedance of a theoretically ideal op-amp? Very low Very high 100 ohms 1000 ohms E6B27 What is a phase-locked loop circuit? An electronic servo loop consisting of a ratio detector, reactance modulator, and voltage-controlled oscillator An electronic circuit also known as a monostable multivibrator An electronic servo loop consisting of a phase detector, a low-pass filter and voltage-controlled oscillator An electronic circuit consisting of a precision push-pull amplifier with a differential input E6B28 What functions are performed by a phase-locked loop? Wide-band AF and RF power amplification Comparison of two digital input signals, digital pulse counter Photovoltaic conversion, optical coupling Frequency synthesis, FM demodulation E6C01 What is the recommended power supply voltage for TTL series integrated circuits? 12 volts 1.5 volts 5 volts 13.6 volts E6C02 What logic state do the inputs of a TTL device assume if they are left open? A high-logic state A low-logic state The device becomes randomized and will not provide consistent high or low-logic states Open inputs on a TTL device are ignored E6C03 What level of input voltage is high in a TTL device operating with a 5- volt power supply? 2.0 to 5.5 volts 1.5 to 3.0 volts 1.0 to 1.5 volts -5.0 to -2.0 volts E6C04 What level of input voltage is low in a TTL device operating with a 5- volt power-supply? -2.0 to -5.5 volts 2.0 to 5.5 volts 0.0 to 0.8 volts -0.8 to 0.4 volts E6C05 What is NOT a major advantage of CMOS over other devices? Small size Low power consumption Low cost Differential output E6C06 Why do CMOS digital integrated circuits have high immunity to noise on the input signal or power supply? Larger bypass capacitors are used in CMOS circuit design The input switching threshold is about two times the power supply voltage The input switching threshold is about one-half the power supply voltage Input signals are stronger E6C07 In Figure E6-5, what is the schematic symbol for an AND gate? 1 2 3 4 E6C08 In Figure E6-5, what is the schematic symbol for a NAND gate? 1 2 3 4 E6C09 In Figure E6-5, what is the schematic symbol for an OR gate? 2 3 4 6 E6C10 In Figure E6-5, what is the schematic symbol for a NOR gate? 1 2 3 4 E6C11 In Figure E6-5, what is the schematic symbol for the NOT operation (inverter)? 2 4 5 6 E6D01 How is the electron beam deflected in a vidicon? By varying the beam voltage By varying the bias voltage on the beam forming grids inside the tube By varying the beam current By varying electromagnetic fields E6D02 What is cathode ray tube (CRT) persistence? The time it takes for an image to appear after the electron beam is turned on The relative brightness of the display under varying conditions of ambient light The ability of the display to remain in focus under varying conditions 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? The image size will decrease and the tube will produce X-rays The image size will increase and the tube will produce X-rays The image will become larger and brighter There will be no apparent change E6D04 Exceeding what design rating can cause a cathode ray tube (CRT) to generate X-rays? The heater voltage The anode voltage The operating temperature The operating frequency E6D05 Which of the following is true of a charge-coupled device (CCD)? Its phase shift changes rapidly with frequency It is a CMOS analog-to-digital converter It samples an analog signal and passes it in stages from the input to the output It is used in a battery charger circuit E6D06 What function does a charge-coupled device (CCD) serve in a modern video camera? It stores photogenerated charges as signals corresponding to pixels It generates the horizontal pulses needed for electron beam scanning It focuses the light used to produce a pattern of electrical charges corresponding to the image It combines audio and video information to produce a composite RF signal E6D07 What is a liquid-crystal display (LCD)? A modern replacement for a quartz crystal oscillator which displays its fundamental frequency A display that uses a crystalline liquid to change the way light is refracted A frequency-determining unit for a transmitter or receiver 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? Core load current Core resistance Core reactivity Core permeability E6D09 By careful selection of core material, over what frequency range can toroidal cores produce useful inductors? From a few kHz to no more than several MHz From 100 Hz to at least 1000 MHz From 100 Hz to no more than 3000 kHz From a few hundred MHz to at least 1000 GHz E6D10 What is one important reason for using powdered-iron toroids rather than ferrite toroids in an inductor? Powdered-iron toroids generally have greater initial permeabilities Powdered-iron toroids generally have better temperature stability Powdered-iron toroids generally require fewer turns to produce given inductance value Powdered-iron toroids are easier to use with surface-mount technology E6D11 What devices are commonly used as VHF and UHF parasitic suppressors at the input and output terminals of transistorized HF amplifiers? Electrolytic capacitors Butterworth filters Ferrite beads Steel-core toroids E6D12 What is a primary advantage of using a toroidal core instead of a solenoidal core in an inductor? Toroidal cores contain 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 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? 2 turns 4 turns 43 turns 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? 35 turns 13 turns 79 turns 141 turns E6D15 What type of CRT deflection is better when high-frequency waves are to be displayed on the screen? Electromagnetic Tubular Radar Electrostatic E6D16 Which is NOT true of a charge-coupled device (CCD)? It uses a combination of analog and digital circuitry It can be used to make an audio delay line It can be used as an analog-to-digital converter It samples and stores analog signals E6D17 What is the principle advantage of liquid-crystal display (LCD) devices? They consume low power They can display changes instantly They are visible in all light conditions They can be easily interchanged with other display devices E6D18 What is one important reason for using ferrite toroids rather than powdered-iron toroids in an inductor? Ferrite toroids generally have lower initial permeabilities Ferrite toroids generally have better temperature stability Ferrite toroids generally require fewer turns to produce a given inductance value Ferrite toroids are easier to use with surface mount technology E6E01 For single-sideband phone emissions, what would be the bandwidth of a good crystal lattice band-pass filter? 6 kHz at -6 dB 2.1 kHz at -6 dB 500 Hz at -6 dB 15 kHz at -6 dB E6E02 For double-sideband phone emissions, what would be the bandwidth of a good crystal lattice band-pass filter? 1 kHz at -6 dB 500 Hz at -6 dB 6 kHz at -6 dB 15 kHz at -6 dB E6E03 What is a crystal lattice filter? A power supply filter made with interlaced quartz crystals An audio filter made with four quartz crystals that resonate at 1-kHz intervals A filter with wide bandwidth and shallow skirts made using quartz crystals 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? Obtain a small quantity of custom-made crystals Choose a crystal with the desired bandwidth and operating frequency to match a desired center frequency Measure crystal bandwidth to ensure at least 20% coupling 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? The relative frequencies of the individual crystals The DC voltage applied to the quartz crystal The gain of the RF stage preceding the filter The amplitude of the signals passing through the filter E6E06 What is the piezoelectric effect? Physical deformation of a crystal by the application of a voltage Mechanical deformation of a crystal by the application of a magnetic field The generation of electrical energy by the application of light Reversed conduction states when a P-N junction is exposed to light E6E07 What is the characteristic impedance of circuits in which MMICs are designed to work? 50 ohms 300 ohms 450 ohms 10 ohms E6E08 What is the typical noise figure of a monolithic microwave integrated circuit (MMIC) amplifier? Less than 1 dB Approximately 3.5 to 6 dB Approximately 8 to 10 dB More than 20 dB E6E09 What type of amplifier device consists of a small pill sized package with an input lead, an output lead and 2 ground leads? A junction field-effect transistor (JFET) An operational amplifier integrated circuit (OAIC) An indium arsenide integrated circuit (IAIC) A monolithic microwave integrated circuit (MMIC) E6E10 What typical construction technique do amateurs use when building an amplifier for the microwave bands containing a monolithic microwave integrated circuit (MMIC)? Ground-plane "ugly" construction Microstrip construction Point-to-point construction Wave-soldering construction E6E11 How is the operating bias voltage supplied to a monolithic microwave integrated circuit (MMIC) that uses four leads? Through a resistor and 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 E6E12 How is the DC power from a voltage source fed to a monolithic microwave integrated circuits (MMIC)? Through a coupling capacitor Through a PIN diode Through a silicon-controlled rectifier Through a resistor E6E13 What supply voltage do monolithic microwave integrated circuits (MMIC) amplifiers typically require? 1 volt DC 12 volts DC 20 volts DC 120 volts DC E6E14 What is the most common package for inexpensive monolithic microwave integrated circuit (MMIC) amplifiers? Beryllium oxide packages Glass packages Plastic packages Ceramic packages |
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