QRZ! Ham Radio 1

home *** CD-ROM | disk | FTP | other *** search

/ QRZ! Ham Radio 1 / QRZ Ham Radio Callsign Database - December 1993.iso / arrl / polextra.2 < prev next >

Wrap

Text File | 1993-11-21 | 54KB | 1,506 lines

Continued from file EXTRA-1.ASC... 4BD-3A.2 What is the proper procedure for suppressing electrical noise in a mobile station? A. Apply shielding and filtering where necessary B. Insulate all plane sheet metal surfaces from each other C. Apply antistatic spray liberally to all non-metallic surfaces D. Install filter capacitors in series with all DC wiring 4BD-3A.3 How can ferrite beads be used to suppress ignition noise? A. Install them in the resistive high voltage cable every 2 years B. Install them between the starter solenoid and the starter motor C. Install them in the primary and secondary ignition leads D. Install them in the antenna lead to the radio 4BD-3A.4 How can ensuring good electrical contact between connecting metal surfaces in a vehicle reduce spark plug noise? A. It reduces the spark gap distance, causing a lower frequency spark B. It helps radiate the spark plug noise away from the vehicle C. It reduces static buildup on the vehicle body D. It encourages lower frequency electrical resonances in the vehicle 4BD-3B.1 How can ++++alternator whine++++ be minimized? A. By connecting the radio's power leads to the battery by the longest possible path B. By connecting the radio's power leads to the battery by the shortest possible path C. By installing a high pass filter in series with the radio's DC power lead to the vehicle's electrical system D. By installing filter capacitors in series with the DC power lead 4BD-3B.2 How can conducted and radiated noise caused by an automobile alternator be suppressed? A. By installing filter capacitors in series with the DC power lead and by installing a blocking capacitor in the field lead B. By connecting the radio's power leads to the battery by the longest possible path and by installing a blocking capacitor in series with the positive lead C. By installing a high pass filter in series with the radio's power lead to the vehicle's electrical system and by installing a low-pass filter in parallel with the field lead D. By connecting the radio's power leads directly to the battery and by installing coaxial capacitors in the alternator leads 4BD-3C.1 What is a major cause of atmospheric static? A. Sunspots B. Thunderstorms C. Airplanes D. Meteor showers 4BD-3D.1 How can you determine if a line-noise interference problem is being generated within your home? A. Check the power-line voltage with a time-domain reflectometer B. Observe the AC waveform on an oscilloscope C. Turn off the main circuit breaker and listen on a battery- operated radio D. Observe the power-line voltage on a spectrum analyzer 4BD-4.1 What is the main drawback of a wire-loop antenna for direction finding? A. It has a bidirectional pattern broadside to the loop B. It is non-rotatable C. It receives equally well in all directions D. It is practical for use only on VHF bands 4BD-4.2 What directional pattern is desirable for a direction- finding antenna? A. A non-cardioid pattern B. Good front-to-back and front-to-side ratios C. Good top-to-bottom and front-to-side ratios D. Shallow nulls 4BD-4.3 What is the ++++triangulation method++++ of direction finding? A. Using the geometric angle of ground waves and sky waves emanating from the same source to locate the signal source B. A fixed receiving station uses three beam headings to plot the signal source on a map C. Beam headings from several receiving locations are used to plot the signal source on a map D. The use of three vertical antennas to indicate the location of the signal source 4BD-4.4 Why is an RF attenuator desirable in a receiver used for direction finding? A. It narrows the bandwidth of the received signal B. It eliminates the effects of isotropic radiation C. It reduces loss of received signals caused by antenna pattern nulls D. It prevents receiver overload from extremely strong signals 4BD-4.5 What is a ++++sense antenna++++? A. A vertical antenna added to a loop antenna to produce a cardioid reception pattern B. A horizontal antenna added to a loop antenna to produce a cardioid reception pattern C. A vertical antenna added to an Adcock antenna to produce an omnidirectional reception pattern D. A horizontal antenna added to an Adcock antenna to produce a cardioid reception pattern 4BD-4.6 What type of antenna is most useful for sky-wave reception in radio direction finding? A. A log-periodic dipole array B. An isotropic antenna C. A circularly polarized antenna D. An Adcock antenna 4BD-4.7 What is a ++++loop antenna++++? A. A circularly polarized antenna B. A coil of wire used as an antenna in FM broadcast receivers C. A wire loop used in radio direction finding D. An antenna coupled to the feed line through an inductive loop of wire 4BD-4.8 How can the output voltage of a loop antenna be increased? A. By reducing the permeability of the loop shield B. By increasing the number of wire turns in the loop while reducing the area of the loop structure C. By reducing either the number of wire turns in the loop, or the area of the loop structure D. By increasing either the number of wire turns in the loop, or the area of the loop structure 4BD-4.9 Why is an antenna system with a cardioid pattern desirable for a direction-finding system? A. The broad side responses of the cardioid pattern can be aimed at the desired station B. The deep null of the cardioid pattern can pinpoint the direction of the desired station C. The sharp peak response of the cardioid pattern can pinpoint the direction of the desired station D. The high radiation angle of the cardioid pattern is useful for short-distance direction finding 4BD-4.10 What type of terrain can cause errors in direction finding? A. Homogeneous terrain B. Smooth grassy terrain C. Varied terrain D. Terrain with no buildings or mountains 4BE-1.1 What is the ++++photoconductive effect++++? A. The conversion of photon energy to electromotive energy B. The increased conductivity of an illuminated semiconductor junction C. The conversion of electromotive energy to photon energy D. The decreased conductivity of an illuminated semiconductor junction 4BE-1.2 What happens to photoconductive material when light shines on it? A. The conductivity of the material increases B. The conductivity of the material decreases C. The conductivity of the material stays the same D. The conductivity of the material becomes temperature dependent 4BE-1.3 What happens to the resistance of a photoconductive material when light shines on it? A. It increases B. It becomes temperature dependent C. It stays the same D. It decreases 4BE-1.4 What happens to the conductivity of a semiconductor junction when it is illuminated? A. It stays the same B. It becomes temperature dependent C. It increases D. It decreases 4BE-1.5 What is an ++++optocoupler++++? A. A resistor and a capacitor B. A frequency modulated helium-neon laser C. An amplitude modulated helium-neon laser D. An LED and a phototransistor 4BE-1.6 What 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. An LED and a solar cell 4BE-1.7 What is an ++++optical shaft encoder++++? A. An array of optocouplers chopped by a stationary wheel B. An array of optocouplers whose light transmission path is controlled by a rotating wheel C. An array of optocouplers whose propagation velocity is controlled by a stationary wheel D. An array of optocouplers whose propagation velocity is controlled by a rotating wheel 4BE-1.8 What does the ++++photoconductive effect++++ in crystalline solids produce a noticeable change in? A. The capacitance of the solid B. The inductance of the solid C. The specific gravity of the solid D. The resistance of the solid 4BE-2A.1 What is the meaning of the term ++++time constant++++ of an RC circuit? A. The time required to charge the capacitor in the circuit to 36.8% of the supply voltage B. The time required to charge the capacitor in the circuit to 36.8% of the supply current C. The time required to charge the capacitor in the circuit to 63.2% of the supply current D. The time required to charge the capacitor in the circuit to 63.2% of the supply voltage 4BE-2A.2 What is the meaning of the term ++++time constant++++ of an RL circuit? A. The time required for the current in the circuit to build up to 36.8% of the maximum value B. The time required for the voltage in the circuit to build up to 63.2% of the maximum value C. The time required for the current in the circuit to build up to 63.2% of the maximum value D. The time required for the voltage in the circuit to build up to 36.8% of the maximum value 4BE-2A.3 What is the term for the time required for the capacitor in an RC circuit to be charged to 63.2% of the supply voltage? A. An exponential rate of one B. One time constant C. One exponential period D. A time factor of one 4BE-2A.4 What is the term for the time required for the current in an RL circuit to build up to 63.2% of the maximum value? A. One time constant B. An exponential period of one C. A time factor of one D. One exponential rate 4BE-2A.5 What is the term for the time it takes for a charged capacitor in an RC circuit to discharge to 36.8% of its initial value of stored charge? A. One discharge period B. An exponential discharge rate of one C. A discharge factor of one D. One time constant 4BE-2A.6 What is meant by ++++back EMF++++? A. A current equal to the applied EMF B. An opposing EMF equal to R times C (RC) percent of the applied EMF C. A current that opposes the applied EMF D. A voltage that opposes the applied EMF 4BE-2B.1 After two time constants, the capacitor in an RC circuit is charged to what percentage of the supply voltage? A. 36.8% B. 63.2% C. 86.5% D. 95% 4BE-2B.2 After two time constants, the capacitor in an RC circuit is discharged to what percentage of the starting voltage? A. 86.5% B. 63.2% C. 36.8% D. 13.5% 4BE-2B.3 What is the time constant of a circuit having a 100- microfarad capacitor in series with a 470-kilohm resistor? A. 4700 seconds B. 470 seconds C. 47 seconds D. 0.47 seconds 4BE-2B.4 What is the time constant of a circuit having a 220- microfarad capacitor in parallel with a 1-megohm resistor? A. 220 seconds B. 22 seconds C. 2.2 seconds D. 0.22 seconds 4BE-2B.5 What is the time constant of a circuit having two 100- microfarad capacitors and two 470-kilohm resistors all in series? A. 470 seconds B. 47 seconds C. 4.7 seconds D. 0.47 seconds 4BE-2B.6 What is the time constant of a circuit having two 100- microfarad capacitors and two 470-kilohm resistors all in parallel? A. 470 seconds B. 47 seconds C. 4.7 seconds D. 0.47 seconds 4BE-2B.7 What is the time constant of a circuit having two 220- microfarad capacitors and two 1-megohm resistors all in series? A. 55 seconds B. 110 seconds C. 220 seconds D. 440 seconds 4BE-2B.8 What is the time constant of a circuit having two 220- microfarad capacitors and two 1-megohm resistors all in parallel? A. 22 seconds B. 44 seconds C. 220 seconds D. 440 seconds 4BE-2B.9 What is the time constant of a circuit having one 100- microfarad capacitor, one 220-microfarad capacitor, one 470- kilohm resistor and one 1-megohm resistor all in series? A. 68.8 seconds B. 101.1 seconds C. 220.0 seconds D. 470.0 seconds 4BE-2B.10 What is the time constant of a circuit having a 470- microfarad capacitor and a 1-megohm resistor in parallel? A. 0.47 seconds B. 47 seconds C. 220 seconds D. 470 seconds 4BE-2B.11 What is the time constant of a circuit having a 470- microfarad capacitor in series with a 470-kilohm resistor? A. 221 seconds B. 221000 seconds C. 470 seconds D. 470000 seconds 4BE-2B.12 What is the time constant of a circuit having a 220- microfarad capacitor in series with a 470-kilohm resistor? A. 103 seconds B. 220 seconds C. 470 seconds D. 470000 seconds 4BE-2B.13 How long does it take for an initial charge of 20 V DC to decrease to 7.36 V DC in a 0.01-microfarad capacitor when a 2- megohm resistor is connected across it? A. 12.64 seconds B. 0.02 seconds C. 1 second D. 7.98 seconds 4BE-2B.14 How long does it take for an initial charge of 20 V DC to decrease to 2.71 V DC in a 0.01-microfarad capacitor when a 2- megohm resistor is connected across it? A. 0.04 seconds B. 0.02 seconds C. 7.36 seconds D. 12.64 seconds 4BE-2B.15 How long does it take for an initial charge of 20 V DC to decrease to 1 V DC in a 0.01-microfarad capacitor when a 2- megohm resistor is connected across it? A. 0.01 seconds B. 0.02 seconds C. 0.04 seconds D. 0.06 seconds 4BE-2B.16 How long does it take for an initial charge of 20 V DC to decrease to 0.37 V DC in a 0.01-microfarad capacitor when a 2- megohm resistor is connected across it? A. 0.08 seconds B. 0.6 seconds C. 0.4 seconds D. 0.2 seconds 4BE-2B.17 How long does it take for an initial charge of 20 V DC to decrease to 0.13 V DC in a 0.01-microfarad capacitor when a 2- megohm resistor is connected across it? A. 0.06 seconds B. 0.08 seconds C. 0.1 seconds D. 1.2 seconds 4BE-2B.18 How long does it take for an initial charge of 800 V DC to decrease to 294 V DC in a 450-microfarad capacitor when a 1- megohm resistor is connected across it? A. 80 seconds B. 294 seconds C. 368 seconds D. 450 seconds 4BE-2B.19 How long does it take for an initial charge of 800 V DC to decrease to 108 V DC in a 450-microfarad capacitor when a 1- megohm resistor is connected across it? A. 225 seconds B. 294 seconds C. 450 seconds D. 900 seconds 4BE-2B.20 How long does it take for an initial charge of 800 V DC to decrease to 39.9 V DC in a 450-microfarad capacitor when a 1- megohm resistor is connected across it? A. 1350 seconds B. 900 seconds C. 450 seconds D. 225 seconds 4BE-2B.21 How long does it take for an initial charge of 800 V DC to decrease to 40.2 V DC in a 450-microfarad capacitor when a 1- megohm resistor is connected across it? A. Approximately 225 seconds B. Approximately 450 seconds C. Approximately 900 seconds D. Approximately 1350 seconds 4BE-2B.22 How long does it take for an initial charge of 800 V DC to decrease to 14.8 V DC in a 450-microfarad capacitor when a 1- megohm resistor is connected across it? A. Approximately 900 seconds B. Approximately 1350 seconds C. Approximately 1804 seconds D. Approximately 2000 seconds 4BE-3.1 What is a ++++Smith Chart++++? A. A graph for calculating impedance along transmission lines B. A graph for calculating great circle bearings C. A graph for calculating antenna height D. A graph for calculating radiation patterns 4BE-3.2 What type of coordinate system is used in a ++++Smith Chart++++? A. Voltage and current circles B. Resistance and reactance circles C. Voltage and current lines D. Resistance and reactance lines 4BE-3.3 What type of calculations can be performed using a ++++Smith Chart++++? A. Beam headings and radiation patterns B. Satellite azimuth and elevation bearings C. Impedance and SWR values in transmission lines D. Circuit gain calculations 4BE-3.4 What are the two families of circles that make up a ++++Smith Chart++++? A. Resistance and voltage B. Reactance and voltage C. Resistance and reactance D. Voltage and impedance 4BE-3.5 What is the only straight line on a blank ++++Smith Chart++++? A. The reactance axis B. The resistance axis C. The voltage axis D. The current axis 4BE-3.6 What is the process of ++++normalizing++++ with regard to a Smith Chart? A. Reassigning resistance values with regard to the reactance axis B. Reassigning reactance values with regard to the resistance axis C. Reassigning resistance values with regard to the prime center D. Reassigning prime center with regard to the reactance axis 4BE-3.7 What are the curved lines on a ++++Smith Chart++++? A. Portions of current circles B. Portions of voltage circles C. Portions of resistance circles D. Portions of reactance circles 4BE-3.8 What is the third family of circles, which are added to a ++++Smith Chart++++ during the process of solving problems? A. Coaxial length circles B. Antenna length circles C. Standing wave ratio circles D. Radiation pattern circles 4BE-3.9 How are the ++++wavelength scales++++ on a Smith Chart calibrated? A. In portions of transmission line electrical frequency B. In portions of transmission line electrical wavelength C. In portions of antenna electrical wavelength D. In portions of antenna electrical frequency 4BE-4.1 What is the impedance of a network comprised of a 0.1- microhenry inductor in series with a 20-ohm resistor, at 30 MHz? (Specify your answer in rectangular coordinates.) A. 20 + ++++j++++19 B. 20 - ++++j++++19 C. 19 + ++++j++++20 D. 19 - ++++j++++20 4BE-4.2 What is the impedance of a network comprised of a 0.1- microhenry inductor in series with a 30-ohm resistor, at 5 MHz? (Specify your answer in rectangular coordinates.) A. 30 - ++++j++++3 B. 30 + ++++j++++3 C. 3 + ++++j++++30 D. 3 - ++++j++++30 4BE-4.3 What is the impedance of a network comprised of a 10- microhenry inductor in series with a 40-ohm resistor, at 500 MHz? (Specify your answer in rectangular coordinates.) A. 40 + ++++j++++31400 B. 40 - ++++j++++31400 C. 31400 + ++++j++++40 D. 31400 - ++++j++++40 4BE-4.4 What is the impedance of a network comprised of a 100- picofarad capacitor in parallel with a 4000-ohm resistor, at 500 kHz? (Specify your answer in polar coordinates.) A. 2490 ohms, ++++/++++_++++51.5++++_++++degrees++++__ B. 4000 ohms, ++++/++++_++++38.5++++_++++degrees++++__ C. 5112 ohms, ++++/++++_++++-38.5++++_++++degrees++++__ D. 2490 ohms, ++++/++++_++++-51.5++++_++++degrees++++__ 4BE-4.5 What is the impedance of a network comprised of a 0.001- microfarad capacitor in series with a 400-ohm resistor, at 500 kHz? (Specify your answer in rectangular coordinates.) A. 400 - ++++j++++318 B. 318 - ++++j++++400 C. 400 + ++++j++++318 D. 318 + ++++j++++400 4BE-5.1 What is the impedance of a network comprised of a 100- ohm-reactance inductor in series with a 100-ohm resistor? (Specify your answer in polar coordinates.) A. 121 ohms, ++++/++++_++++35++++_++++degrees++++__ B. 141 ohms, ++++/++++_++++45++++_++++degrees++++__ C. 161 ohms, ++++/++++_++++55++++_++++degrees++++__ D. 181 ohms, ++++/++++_++++65++++_++++degrees++++__ 4BE-5.2 What is the impedance of a network comprised of a 100- ohm-reactance inductor, a 100-ohm-reactance capacitor, and a 100- ohm resistor all connected in series? (Specify your answer in polar coordinates.) A. 100 ohms, ++++/++++_++++90++++_++++degrees++++__ B. 10 ohms, ++++/++++_++++0++++_++++degrees++++__ C. 100 ohms, ++++/++++_++++0++++_++++degrees++++__ D. 10 ohms, ++++/++++_++++100++++_++++degrees++++__ 4BE-5.3 What is the impedance of a network comprised of a 400- ohm-reactance capacitor in series with a 300-ohm resistor? (Specify your answer in polar coordinates.) A. 240 ohms, ++++/++++_++++36.9++++_++++degrees++++___ B. 240 ohms, ++++/++++_++++-36.9++++_++++degrees++++__ C. 500 ohms, ++++/++++_++++53.1++++_++++degrees++++___ D. 500 ohms, ++++/++++_++++-53.1++++_++++degrees++++__ 4BE-5.4 What is the impedance of a network comprised of a 300- ohm-reactance capacitor, a 600-ohm-reactance inductor, and a 400- ohm resistor, all connected in series? (Specify your answer in polar coordinates.) A. 500 ohms, ++++/++++_++++37++++_++++degrees++++__ B. 400 ohms, ++++/++++_++++27++++_++++degrees++++__ C. 300 ohms, ++++/++++_++++17++++_++++degrees++++__ D. 200 ohms, ++++/++++_++++10++++_++++degrees++++__ 4BE-5.5 What is the impedance of a network comprised of a 400- ohm-reactance inductor in parallel with a 300-ohm resistor? (Specify your answer in polar coordinates.) A. 240 ohms, ++++/++++_++++36.9++++_++++degrees++++___ B. 240 ohms, ++++/++++_++++-36.9++++_++++degrees++++__ C. 500 ohms, ++++/++++_++++53.1++++_++++degrees++++__ D. 500 ohms, ++++/++++_++++-53.1++++_++++degrees++++__ 4BE-6A.1 What is the impedance of a network comprised of a 1.0- millihenry inductor in series with a 200-ohm resistor, at 30 kHz? (Specify your answer in rectangular coordinates.) A. 200 - ++++j++++188 B. 200 + ++++j++++188 C. 188 + ++++j++++200 D. 188 - ++++j++++200 4BE-6A.2 What is the impedance of a network comprised of a 10- millihenry inductor in series with a 600-ohm resistor, at 10 kHz? (Specify your answer in rectangular coordinates.) A. 628 + ++++j++++600 B. 628 - ++++j++++600 C. 600 + ++++j++++628 D. 600 - ++++j++++628 4BE-6A.3 What is the impedance of a network comprised of a 0.01- microfarad capacitor in parallel with a 300-ohm resistor, at 50 kHz? (Specify your answer in rectangular coordinates.) A. 150 - ++++j++++159 B. 150 + ++++j++++159 C. 159 + ++++j++++150 D. 159 - ++++j++++150 4BE-6A.4 What is the impedance of a network comprised of a 0.1- microfarad capacitor in series with a 40-ohm resistor, at 50 kHz? (Specify your answer in rectangular coordinates.) A. 40 + ++++j++++32 B. 40 - ++++j++++32 C. 32 - ++++j++++40 D. 32 + ++++j++++40 4BE-6A.5 What is the impedance of a network comprised of a 1.0- microfarad capacitor in parallel with a 30-ohm resistor, at 5 MHz? (Specify your answer in rectangular coordinates.) A. 0.000034 + ++++j++++.032 B. 0.032 + ++++j++++.000034 C. 0.000034 - ++++j++++.032 D. 0.032 - ++++j++++.000034 4BE-6B.1 What is the impedance of a network comprised of a 100- ohm-reactance capacitor in series with a 100-ohm resistor? (Specify your answer in polar coordinates.) A. 121 ohms, ++++/++++_++++-25++++_++++degrees++++__ B. 141 ohms, ++++/++++_++++-45++++_++++degrees++++__ C. 161 ohms, ++++/++++_++++-65++++_++++degrees++++__ D. 191 ohms, ++++/++++_++++-85++++_++++degrees++++__ 4BE-6B.2 What is the impedance of a network comprised of a 100- ohm-reactance capacitor in parallel with a 100-ohm resistor? (Specify your answer in polar coordinates.) A. 31 ohms, ++++/++++_++++-15++++_++++degrees++++__ B. 51 ohms, ++++/++++_++++-25++++_++++degrees++++__ C. 71 ohms, ++++/++++_++++-45++++_++++degrees++++__ D. 91 ohms, ++++/++++_++++-65++++_++++degrees++++__ 4BE-6B.3 What is the impedance of a network comprised of a 300- ohm-reactance inductor in series with a 400-ohm resistor? (Specify your answer in polar coordinates.) A. 400 ohms, ++++/++++_++++27++++_++++degrees++++__ B. 500 ohms, ++++/++++_++++37++++_++++degrees++++__ C. 600 ohms, ++++/++++_++++47++++_++++degrees++++__ D. 700 ohms, ++++/++++_++++57++++_++++degrees++++__ 4BE-6B.4 What is the impedance of a network comprised of a 100- ohm-reactance inductor in parallel with a 100-ohm resistor? (Specify your answer in polar coordinates.) A. 71 ohms, ++++/++++_++++45++++_++++degrees++++_ B. 81 ohms, ++++/++++_++++55++++_++++degrees++++__ C. 91 ohms, ++++/++++_++++65++++_++++degrees++++__ D. 100 ohms, ++++/++++_++++75++++_++++degrees++++__ 4BE-6B.5 What is the impedance of a network comprised of a 300- ohm-reactance capacitor in series with a 400-ohm resistor? (Specify your answer in polar coordinates.) A. 200 ohms, ++++/++++_++++-10++++_++++degrees++++__ B. 300 ohms, ++++/++++_++++-17++++_++++degrees++++__ C. 400 ohms, ++++/++++_++++-27++++_++++degrees++++__ D. 500 ohms, ++++/++++_++++-37++++_++++degrees++++__ 4BF-1A.1 What is an ++++enhancement-mode++++ FET? A. An FET with a channel that blocks voltage through the gate B. An FET with a channel that allows a current when the gate voltage is zero C. An FET without a channel to hinder current through the gate D. An FET without a channel; no current occurs with zero gate voltage 4BF-1B.1 What is a ++++depletion-mode++++ FET? A. An FET that has a channel with no gate voltage applied; a current flows with zero gate voltage B. An FET that has a channel that blocks current when the gate voltage is zero C. An FET without a channel; no current flows with zero gate voltage D. An FET without a channel to hinder current through the gate 4BF-1C.1 What is the schematic symbol for an N-channel MOSFET [see graphics addendum]? A. 1 B. 2 C. 3 D. 4 4BF-1C.2 What is the schematic symbol for a P-channel MOSFET [see graphics addendum]? A. 1 B. 2 C. 3 D. 4 4BF-1C.3 What is the schematic symbol for an N-channel dual-gate MOSFET [see graphics addendum]? A. 1 B. 2 C. 3 D. 4 4BF-1C.4 What is the schematic symbol for a P-channel dual-gate MOSFET [see graphics addendum]? A. 1 B. 2 C. 3 D. 4 4BF-1C.5 Why do many MOSFET devices have built-in gate-protective Zener diodes? A. The gate-protective Zener diode provides a voltage reference to provide the correct amount of reverse-bias gate voltage B. The gate-protective Zener diode protects the substrate from excessive voltages C. The gate-protective Zener diode keeps the gate voltage within specifications to prevent the device from overheating D. The gate-protective Zener diode prevents the gate insulation from being punctured by small static charges or excessive voltages 4BF-1D.1 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 4BF-1D.2 Why are special precautions necessary in handling FET and CMOS devices? A. They are susceptible to damage from static charges B. They have fragile leads that may break off C. They have micro-welded semiconductor junctions that are susceptible to breakage D. They are light sensitive 4BF-1E.1 What is the schematic symbol for an N-channel junction FET [see graphics addendum]? A. 1 B. 2 C. 3 D. 4 4BF-1E.2 How does the input impedance of a ++++field-effect transistor++++ compare with that of a bipolar transistor? A. One cannot compare input impedance without first knowing the supply voltage B. An FET has low input impedance; a bipolar transistor has high input impedance C. The input impedance of FETs and bipolar transistors is the same D. An FET has high input impedance; a bipolar transistor has low input impedance 4BF-1E.3 What are 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 4BF-1F.1 What is the schematic symbol for a P-channel junction FET [see graphics addendum]? A. 1 B. 2 C. 3 D. 4 4BF-1F.2 What are the two basic types of junction ++++field-effect transistors++++? A. N-channel and P-channel B. High power and low power C. MOSFET and GaAsFET D. Silicon FET and germanium FET 4BF-2.1 What is an ++++operational amplifier++++? A. A high-gain, direct-coupled differential amplifier whose characteristics are determined by components external to the amplifier unit B. A high-gain, direct-coupled audio amplifier whose characteristics are determined by components external to the amplifier unit C. An amplifier used to increase the average output of frequency modulated amateur signals to the legal limit D. A program subroutine that calculates the gain of an RF amplifier 4BF-2.2 What is the schematic symbol for an ++++operational amplifier++++ [see graphics addendum]? A. 1 B. 2 C. 3 D. 4 4BF-2.3 What would be the characteristics of the ideal op-amp? A. Zero input impedance, infinite output impedance, infinite gain, flat frequency response B. Infinite input impedance, zero output impedance, infinite gain, flat frequency response C. Zero input impedance, zero output impedance, infinite gain, flat frequency response D. Infinite input impedance, infinite output impedance, infinite gain, flat frequency response 4BF-2.4 What determines the gain of a closed-loop op-amp circuit? A. The external feedback network B. The collector-to-base capacitance of the PNP stage C. The power supply voltage D. The PNP collector load 4BF-2.5 What is meant by the term ++++op-amp offset voltage++++? A. The output voltage of the op-amp minus its input voltage B. The difference between the output voltage of the op-amp and the input voltage required in the following stage C. The potential between the amplifier-input terminals of the op-amp in a closed-loop condition D. The potential between the amplifier-input terminals of the op-amp in an open-loop condition 4BF-2.6 What is the input impedance of a theoretically ideal op- amp? A. 100 ohms B. 1000 ohms C. Very low D. Very high 4BF-2.7 What is the output impedance of a theoretically ideal op- amp? A. Very low B. Very high C. 100 ohms D. 1000 ohms 4BF-3.1 What is a ++++phase-locked loop++++ circuit? A. An electronic servo loop consisting of a ratio detector, reactance modulator, and voltage-controlled oscillator B. An electronic circuit also known as a monostable multivibrator C. An electronic circuit consisting of a precision push-pull amplifier with a differential input D. An electronic servo loop consisting of a phase detector, a low-pass filter and voltage-controlled oscillator 4BF-3.2 What functions are performed by a ++++phase-locked loop++++? A. Wideband AF and RF power amplification B. Comparison of two digital input signals, digital pulse counter C. Photovoltaic conversion, optical coupling D. Frequency synthesis, FM demodulation 4BF-3.3 A circuit compares the output from a voltage-controlled oscillator and a frequency standard. The difference between the two frequencies produces an error voltage that changes the voltage-controlled oscillator frequency. What is the name of the circuit? A. A doubly balanced mixer B. A phase-locked loop C. A differential voltage amplifier D. A variable frequency oscillator 4BF-4.1 What do the initials ++++TTL++++ stand for? A. Resistor-transistor logic B. Transistor-transistor logic C. Diode-transistor logic D. Emitter-coupled logic 4BF-4.2 What is the recommended power supply voltage for ++++TTL++++ series integrated circuits? A. 12.00 volts B. 50.00 volts C. 5.00 volts D. 13.60 volts 4BF-4.3 What logic state do the inputs of a ++++TTL++++ device assume if they are left open? A. A high logic state B. A low logic 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 4BF-4.4 What level of input voltage is ++++high++++ in a ++++TTL++++ device operating with a 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 4BF-4.5 What level of input voltage is ++++low++++ in a ++++TTL++++ device operating with a 5-volt power supply? A. -2.0 to -5.5 volts B. 2.0 to 5.5 volts C. -0.6 to 0.8 volts D. -0.8 to 0.4 volts 4BF-4.6 Why do circuits containing ++++TTL++++ devices have several bypass capacitors per printed circuit board? A. To prevent RFI to receivers B. To keep the switching noise within the circuit, thus eliminating RFI C. To filter out switching harmonics D. To prevent switching transients from appearing on the supply line 4BF-5.1 What is a ++++CMOS IC++++? A. A chip with only P-channel transistors B. A chip with P-channel and N-channel transistors C. A chip with only N-channel transistors D. A chip with only bipolar transistors 4BF-5.2 What is one major advantage of ++++CMOS++++ over other devices? A. Small size B. Low current consumption C. Low cost D. Ease of circuit design 4BF-5.3 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 4BF-6.1 What is the name for a vacuum tube that is commonly found in television cameras used for amateur television? A. A traveling-wave tube B. A klystron tube C. A vidicon tube D. A cathode-ray tube 4BF-6.2 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 4BF-6.3 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 4BG-1A.1 What is a ++++flip-flop++++ circuit? A. A binary sequential logic element with one stable state B. A binary sequential logic element with eight stable states C. A binary sequential logic element with four stable states D. A binary sequential logic element with two stable states 4BG-1A.2 How many bits of information can be stored in a single ++++flip-flop++++ circuit? A. 1 B. 2 C. 3 D. 4 4BG-1A.3 What is a ++++bistable multivibrator++++ circuit? A. An "AND" gate B. An "OR" gate C. A flip-flop D. A clock 4BG-1A.4 How many output changes are obtained for every two trigger pulses applied to the input of a ++++bistable T flip-flop++++ circuit? A. No output level changes B. One output level change C. Two output level changes D. Four output level changes 4BG-1A.5 The frequency of an AC signal can be divided electronically by what type of digital circuit? A. A free-running multivibrator B. An OR gate C. A bistable multivibrator D. An astable multivibrator 4BG-1A.6 What type of digital IC is also known as a ++++latch++++? A. A decade counter B. An OR gate C. A flip-flop D. An op-amp 4BG-1A.7 How many ++++flip-flops++++ are required to divide a signal frequency by 4? A. 1 B. 2 C. 4 D. 8 4BG-1B.1 What is an ++++astable multivibrator++++? A. A circuit that alternates between two stable states B. A circuit that alternates between a stable state and an unstable state C. A circuit set to block either a 0 pulse or a 1 pulse and pass the other D. A circuit that alternates between two unstable states 4BG-1B.2 What is a ++++monostable multivibrator++++? A. A circuit that can be switched momentarily to the opposite binary state and then returns after a set time to its original state B. A "clock" circuit that produces a continuous square wave oscillating between 1 and 0 C. A circuit designed to store one bit of data in either the 0 or the 1 configuration D. A circuit that maintains a constant output voltage, regardless of variations in the input voltage 4BG-1C.1 What is an ++++AND gate++++? A. A circuit that produces a logic "1" at its output only if all inputs are logic "1" B. A circuit that produces a logic "0" at its output only if all inputs are logic "1" C. A circuit that produces a logic "1" at its output if only one input is a logic "1" D. A circuit that produces a logic "1" at its output if all inputs are logic "0" 4BG-1C.2 What is the schematic symbol for an ++++AND gate++++ [see graphics addendum]? A. 1 B. 2 C. 3 D. 4 4BG-1C.3 What is a ++++NAND gate++++? A. A circuit that produces a logic "0" at its output only when all inputs are logic "0" B. A circuit that produces a logic "1" at its output only when all inputs are logic "1" C. A circuit that produces a logic "0" at its output if some but not all of its inputs are logic "1" D. A circuit that produces a logic "0" at its output only when all inputs are logic "1" 4BG-1C.4 What is the schematic symbol for a ++++NAND gate++++ [see graphics addendum]? A. 1 B. 2 C. 3 D. 4 4BG-1C.5 What is an ++++OR gate++++? A. A circuit that produces a logic "1" at its output if any input is logic "1" B. A circuit that produces a logic "0" at its output if any input is logic "1" C. A circuit that produces a logic "0" at its output if all inputs are logic "1" D. A circuit that produces a logic "1" at its output if all inputs are logic "0" 4BG-1C.6 What is the schematic symbol for an ++++OR gate++++ [see graphics addendum]? A. 1 B. 2 C. 3 D. 4 4BG-1C.7 What is a ++++NOR gate++++? A. A circuit that produces a logic "0" at its output only if all inputs are logic "0" B. A circuit that produces a logic "1" at its output only if all inputs are logic "1" C. A circuit that produces a logic "0" at its output if any or all inputs are logic "1" D. A circuit that produces a logic "1" at its output if some but not all of its inputs are logic "1" 4BG-1C.8 What is the schematic symbol for a ++++NOR gate++++ [see graphics addendum]? A. 1 B. 2 C. 3 D. 4 4BG-1C.9 What is a ++++NOT gate++++? A. A circuit that produces a logic "O" at its output when the input is logic "1" and vice versa B. A circuit that does not allow data transmission when its input is high C. A circuit that allows data transmission only when its input is high D. A circuit that produces a logic "1" at its output when the input is logic "1" and vice versa 4BG-1C.10 What is the schematic symbol for a ++++NOT gate++++ [see graphics addendum]? A. 1 B. 2 C. 3 D. 4 4BG-1D.1 What is a ++++truth table++++? A. A table of logic symbols that indicate the high logic states of an op-amp B. A diagram showing logic states when the digital device's output is true C. A list of input combinations and their corresponding outputs that characterizes a digital device's function D. A table of logic symbols that indicates the low logic states of an op-amp 4BG-1D.2 In a positive-logic circuit, what level is used to represent a logic 1? A. A low level B. A positive-transition level C. A negative-transition level D. A high level 4BG-1D.3 In a positive-logic circuit, what level is used to represent a logic 0? A. A low level B. A positive-transition level C. A negative-transition level D. A high level 4BG-1D.4 In a negative-logic circuit, what level is used to represent a logic 1? A. A low level B. A positive-transition level C. A negative-transition level D. A high level 4BG-1D.5 In a negative-logic circuit, what level is used to represent a logic 0? A. A low level B. A positive-transition level C. A negative-transition level D. A high level 4BG-2A.1 What is a ++++crystal-controlled marker generator++++? A. A low-stability oscillator that "sweeps" through a band of frequencies B. An oscillator often used in aircraft to determine the craft's location relative to the inner and outer markers at airports C. A high-stability oscillator whose output frequency and amplitude can be varied over a wide range D. A high-stability oscillator that generates a series of reference signals at known frequency intervals 4BG-2A.2 What additional circuitry is required in a 100-kHz ++++crystal-controlled marker generator++++ to provide markers at 50 and 25 kHz? A. An emitter-follower B. Two frequency multipliers C. Two flip-flops D. A voltage divider 4BG-2B.1 What is the purpose of a ++++prescaler circuit++++? A. It converts the output of a JK flip-flop to that of an RS flip-flop B. It multiplies an HF signal so a low-frequency counter can display the operating frequency C. It prevents oscillation in a low frequency counter circuit D. It divides an HF signal so a low-frequency counter can display the operating frequency 4BG-2B.2 What does the accuracy of a ++++frequency counter++++ depend on? A. The internal crystal reference B. A voltage-regulated power supply with an unvarying output C. Accuracy of the AC input frequency to the power supply D. Proper balancing of the power-supply diodes 4BG-2B.3 How many states does a decade counter digital IC have? A. 6 B. 10 C. 15 D. 20 4BG-2B.4 What is the function of a decade counter digital IC? A. Decode a decimal number for display on a seven-segment LED display B. Produce one output pulse for every ten input pulses C. Produce ten output pulses for every input pulse D. Add two decimal numbers 4BG-3A.1 What are the advantages of using an op-amp instead of LC elements in an audio filter? A. Op-amps are more rugged and can withstand more abuse than can LC elements B. Op-amps are fixed at one frequency C. Op-amps are available in more styles and types than are LC elements D. Op-amps exhibit gain rather than insertion loss 4BG-3A.2 What determines the gain and frequency characteristics of an op-amp RC active filter? A. Values of capacitances and resistances built into the op- amp B. Values of capacitances and resistances external to the op- amp C. Voltage and frequency of DC input to the op-amp power supply D. Regulated DC voltage output from the op-amp power supply 4BG-3A.3 What are the principle uses of an op-amp RC active filter in amateur circuitry? A. Op-amp circuits are used as high-pass filters to block RFI at the input to receivers B. Op-amp circuits are used as low-pass filters between transmitters and transmission lines C. Op-amp circuits are used as filters for smoothing power- supply output D. Op-amp circuits are used as audio filters for receivers 4BG-3B.1 What type of capacitors should be used in an op-amp RC active filter circuit? A. Electrolytic B. Disc ceramic C. Polystyrene D. Paper dielectric 4BG-3B.2 How can unwanted ringing and audio instability be prevented in a multisection op-amp RC audio filter circuit? A. Restrict both gain and Q B. Restrict gain, but increase Q C. Restrict Q, but increase gain D. Increase both gain and Q 4BG-3B.3 Where should an op-amp RC active audio filter be placed in an amateur receiver? A. In the IF strip, immediately before the detector B. In the audio circuitry immediately before the speaker or phone jack C. Between the balanced modulator and frequency multiplier D. In the low-level audio stages 4BG-3B.4 What parameter must be selected when designing an audio filter using an op-amp? A. Bandpass characteristics B. Desired current gain C. Temperature coefficient D. Output-offset overshoot 4BG-4A.1 What two factors determine the ++++sensitivity++++ of a receiver? A. Dynamic range and third-order intercept B. Cost and availability C. Intermodulation distortion and dynamic range D. Bandwidth and noise figure 4BG-4A.2 What is the limiting condition for ++++sensitivity++++ in a communications receiver? A. The noise floor of the receiver B. The power-supply output ripple C. The two-tone intermodulation distortion D. The input impedance to the detector 4BG-4A.3 What is the theoretical minimum ++++noise floor++++ of a receiver with a 400-hertz bandwidth? A. -141 dBm B. -148 dBm C. -174 dBm D. -180 dBm 4BG-4B.1 How can ++++selectivity++++ be achieved in the front-end circuitry of a communications receiver? A. By using an audio filter B. By using a preselector C. By using an additional RF amplifier stage D. By using an additional IF amplifier stage 4BG-4B.2 A receiver selectivity of 2.4 kHz in the IF circuitry is optimum for what type of amateur signals? A. CW B. SSB voice C. Double-sideband AM voice D. FSK RTTY 4BG-4B.3 What occurs during CW reception if too narrow a filter bandwidth is used in the IF stage of a receiver? A. Undesired signals will reach the audio stage B. Output-offset overshoot C. Cross-modulation distortion D. Filter ringing 4BG-4B.4 What degree of selectivity is desirable in the IF circuitry of an amateur RTTY receiver? A. 100 Hz B. 300 Hz C. 6000 Hz D. 2400 Hz 4BG-4B.5 A receiver selectivity of 10 kHz in the IF circuitry is optimum for what type of amateur signals? A. SSB voice B. Double-sideband AM C. CW D. FSK RTTY 4BG-4B.6 What degree of selectivity is desirable in the IF circuitry of a single-sideband phone receiver? A. 1 kHz B. 2.4 kHz C. 4.2 kHz D. 4.8 kHz 4BG-4B.7 What is an undesirable effect of using too wide a filter bandwidth in the IF section of a receiver? A. Output-offset overshoot B. Undesired signals will reach the audio stage C. Thermal-noise distortion D. Filter ringing 4BG-4B.8 How should the filter bandwidth of a receiver IF section compare with the bandwidth of a received signal? A. Filter bandwidth should be slightly greater than the received-signal bandwidth B. Filter bandwidth should be approximately half the received- signal bandwidth C. Filter bandwidth should be approximately two times the received-signal bandwidth D. Filter bandwidth should be approximately four times the received-signal bandwidth 4BG-4B.9 What degree of selectivity is desirable in the IF circuitry of an FM-phone receiver? A. 1 kHz B. 2.4 kHz C. 4.2 kHz D. 15 kHz 4BG-4B.10 How can selectivity be achieved in the IF circuitry of a communications receiver? A. Incorporate a means of varying the supply voltage to the local oscillator circuitry B. Replace the standard JFET mixer with a bipolar transistor followed by a capacitor of the proper value C. Remove AGC action from the IF stage and confine it to the audio stage only D. Incorporate a high-Q filter 4BG-4C.1 What is meant by the ++++dynamic range++++ of a communications receiver? A. The number of kHz between the lowest and the highest frequency to which the receiver can be tuned B. The maximum possible undistorted audio output of the receiver, referenced to one milliwatt C. The ratio between the minimum discernible signal and the largest tolerable signal without causing audible distortion products D. The difference between the lowest-frequency signal and the highest-frequency signal detectable without moving the tuning knob 4BG-4C.2 What is the term for the ratio between the largest tolerable receiver input signal and the minimum discernible signal? A. Intermodulation distortion B. Noise floor C. Noise figure D. Dynamic range 4BG-4C.3 What type of problems are caused by poor ++++dynamic range++++ in a communications receiver? A. Cross-modulation of the desired signal and desensitization from strong adjacent signals B. Oscillator instability requiring frequent retuning, and loss of ability to recover the opposite sideband, should it be transmitted C. Cross-modulation of the desired signal and insufficient audio power to operate the speaker D. Oscillator instability and severe audio distortion of all but the strongest received signals 4BG-4C.4 The ability of a communications receiver to perform well in the presence of strong signals outside the amateur band of interest is indicated by what parameter? A. Noise figure B. Blocking dynamic range C. Signal-to-noise ratio D. Audio output 4BG-4D.1 What is meant by the term ++++noise figure++++ of a communications receiver? A. The level of noise entering the receiver from the antenna B. The relative strength of a received signal 3 kHz removed from the carrier frequency C. The level of noise generated in the front end and succeeding stages of a receiver D. The ability of a receiver to reject unwanted signals at frequencies close to the desired one 4BG-4D.2 Which stage of a receiver primarily establishes its ++++noise figure++++? A. The audio stage B. The IF strip C. The RF stage D. The local oscillator 4BG-5A.1 What is an ++++inverting op-amp circuit++++? A. An operational amplifier circuit connected such that the input and output signals are 180 degrees out of phase B. An operational amplifier circuit connected such that the input and output signals are in phase C. An operational amplifier circuit connected such that the input and output signals are 90 degrees out of phase D. An operational amplifier circuit connected such that the input impedance is held at zero, while the output impedance is high 4BG-5B.1 What is a ++++noninverting op-amp circuit++++? A. An operational amplifier circuit connected such that the input and output signals are 180 degrees out of phase B. An operational amplifier circuit connected such that the input and output signals are in phase C. An operational amplifier circuit connected such that the input and output signals are 90 degrees out of phase D. An operational amplifier circuit connected such that the input impedance is held at zero while the output impedance is high 4BG-5C.1 What voltage gain can be expected from the circuit in Figure 4BG-5 when R1 is 1000 ohms and Rf is 100 kilohms [see graphics addendum]? A. 0.01 B. 1 C. 10 D. 100 4BG-5C.2 What voltage gain can be expected from the circuit in Figure 4BG-5 when R1 is 1800 ohms and Rf is 68 kilohms [see graphics addendum]? A. 1 B. 0.03 C. 38 D. 76 4BG-5C.3 What voltage gain can be expected from the circuit in Figure 4BG-5 when R1 is 3300 ohms and Rf is 47 kilohms [see graphics addendum]? A. 28 B. 14 C. 7 D. 0.07 4BG-5C.4 What voltage gain can be expected from the circuit in Figure 4BG-5 when R1 is 10 ohms and Rf is 47 kilohms [see graphics addendum]? A. 0.00021 B. 9400 C. 4700 D. 2350 4BG-5D.1 How does the gain of a theoretically ideal operational amplifier vary with frequency? A. The gain increases linearly with increasing frequency B. The gain decreases linearly with increasing frequency C. The gain decreases logarithmically with increasing frequency D. The gain does not vary with frequency 4BG-6.1 What determines the input impedance in a FET common- source amplifier? A. The input impedance is essentially determined by the resistance between the drain and substrate B. The input impedance is essentially determined by the resistance between the source and drain C. The input impedance is essentially determined by the gate biasing network D. The input impedance is essentially determined by the resistance between the source and substrate 4BG-6.2 What determines the output impedance in a FET common- source amplifier? A. The output impedance is essentially determined by the drain resistor B. The output impedance is essentially determined by the input impedance of the FET C. The output impedance is essentially determined by the drain supply voltage D. The output impedance is essentially determined by the gate supply voltage 4BG-7.1 What frequency range will be tuned by the circuit in Figure 4BG-7 when L is 10 microhenrys, Cf is 156 picofarads, and Cv is 50 picofarads maximum and 2 picofarads minimum? A. 3508 through 4004 kHz B. 6998 through 7360 kHz C. 13.396 through 14.402 MHz D. 49.998 through 54.101 MHz 4BG-7.2 What frequency range will be tuned by the circuit in Figure 4BG-7 when L is 30 microhenrys, Cf is 200 picofarads, and Cv is 80 picofarads maximum and 10 picofarads minimum? A. 1737 through 2005 kHz B. 3507 through 4004 kHz C. 7002 through 7354 kHz D. 14.990 through 15.020 MHz 4BG-8.1 What is the purpose of a bypass capacitor? A. It increases the resonant frequency of the circuit B. It removes direct current from the circuit by shunting DC to ground C. It removes alternating current by providing a low impedance path to ground D. It acts as a voltage divider 4BG-8.2 What is the purpose of a coupling capacitor? A. It blocks direct current and passes alternating current B. It blocks alternating current and passes direct current C. It increases the resonant frequency of the circuit D. It decreases the resonant frequency of the circuit 4BH-1A.1 In a pulse-width modulation system, what parameter does the modulating signal vary? A. Pulse duration B. Pulse frequency C. Pulse amplitude D. Pulse intensity 4BH-1A.2 What is the type of modulation in which the modulating signal varies the duration of the transmitted pulse? A. Amplitude modulation B. Frequency modulation C. Pulse-width modulation D. Pulse-height modulation See EXTRA-3.ASC for the remainder of this pool plus it's answers...