Shared Flashcard Set

Details

Element 3: General Radiotelephone Operator
FCC Question Pool @2009
168
Communication
05/31/2012

Additional Communication Flashcards

 


 

Cards

Term

3-1A1:  The Product of the readings of an AC voltmeter and AC ammeter is called:

Definition

Apparent power

Term

3-1A2:  What is the basic unit of electrical power?

Definition

Watt

 

Power = P = watt

 

 

Term

3-1A3:  What is the term used to express the amount of electrical energy stored in an electrostatic field?

Definition

Joules

 

Joules = Capacity to do work = Stored in Capacitors = Defibrillators

Term

3-1A4:  What device is used to store electrical energy in an electrostatic field?

Definition

Capacitor

Term

3-1A5:  What formula would determine the inductive reactance of a coil if frequency and coil inductance are known?

Definition

XL = 2 * ∏ * f * L

 

 

 

 

 

 

Term

3-1A6:  What is the term for the out-of-phase power associated with inductors and capacitors?

Definition

Reactive Power

 

Reactive Power = Non-Productive = Out of Phase Power

Term

 3-2A1:  What determines the strength of the magnetic field around a conductor?

Definition

The amount of current

Term

3-2A2:  What will produce a magnetic field?

Definition

A current flowing through a conductor

Term

3-2A3:  When induced currents produce expanding magnetic fields around conductors in a direction that opposes the original magnetic field, this is known as:

Definition

Lenz's Law

Term

3-2A4:  The opposition to the creation of magnetic lines of force in a magnetic circuit is known as:

Definition

Reluctance

Term

3-2A5:  What is meant by the term "back EMF?"

Definition

A voltage that opposes the applied EMF

Term

3-2A6:  Permeability is defined as:

Definition

The ratio of magnetic flux density in a substance to the magnetizing force that produces it

Term

3-3A1:  What metal is usually employed as a sacraficial anode for corrosion control purposes?

Definition

Zinc bar

Term

3-3A2:  What is the relative dielectric constant for air?

Definition

1

Term

3-3A3:  Which metal object may be least affected by galvanic corrosion when submerged in seawater?

Definition

Stainless steel propeller shaft

Term

3-3A4:  Skin effect is the phenomenon where:

Definition

RF current flows in a thin layer of the conductor, closer to the surface, as frequency increases

Term

3-3A5:  Corrosion resulting from electric current flow between dissimilar metals is called:

Definition

Galvanic corrosion

Term

3-3A6:  Which of these will be most useful for insulation at UHF frequencies?

Definition

Mica

 

and Teflon

Term

3-4A1:  What formula would calculate the total inductance of inductors in series?

Definition

LT = L1 + L2

Term

3-4A2:  Good conductors with minimum resistance have what type of electrons?

Definition

Many free electons

Term

3-4A3:  Which of the 4 groups of metals listed below are the best low-resistance conductors?

Definition

Gold, silver and copper

 


Gold, Silver, Copper, Aluminum, Nickel, Iron, Lead

Term

3-4A4:  What is the purpose of a bypass capacitor?

Definition

It removes alternating current by providing a low impedance path to ground

Term

3-4A5:  How would you calculate the total capacitance of three capacitors in parallel?

Definition

CT = C1 + C2 + C3

Term

3-4A6:  How might you reduce the inductance of an antenna coil?

Definition

Reduce the number of turns

Term

3-5A1:  What are the two most commonly-used specifications for a junction diode?

Definition

Maximum forward current and PIV, (peak inverse voltage)

Term

3-5A2:  What limits the maximum forward current in a junction diode?

Definition

The junction temperature

Term

3-5A3:  MOSFETs are manufactured with THIS protective device built into their gate to protect the device from static charges and excessive voltages:

Definition

Zener diode

Term

3-5A4:  What are the two basic types of junction field-effect transistors?

Definition

N-channel and P-channel

Term

3-5A5:  A common emitter amplifier has:

Definition

More voltage gain than a common collector

Term

3-5A6:  How does the input impedance of a field-effect transistor compare with that of a bipolar transistor?

Definition

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

Term

3-6A1:  An AC ammeter indicates:

Definition

Effective (RMS) values of current

Term

3-6A2:  By what factor must the voltage of an AC circuit, as indicated on the scale of an AC voltmeter, be multiplied to obtain the peak voltage value?

Definition

1.414

Term

3-6A3: What is the RMS voltage at a common household electrical power outlet?

Definition

117-V AC

Term

3-6A4:  What is the easiest voltage amplitude to measure by viewing a pure sine wave signal on an oscilloscope?

Definition

Peak-to-peak

Sine Wave goes peak to peak 

Term

3-6A5:  By what factor must the voltage measured in an AC circuit, as indicated on the scale of an AC voltmeter be multiplied to obtain the average voltage value?

Definition

0.9

Term

3-6A6:  What is the peak voltage at a common household electrical outlet?

Definition

165.5 volts

Term

3-7A1:  What is a sine wave?

Definition

A wave whose amplitude at any given instant can be represented by the projection of a point on a wheel rotating at a uniform speed

Term

3-7A2:  How many degrees are there in one complete sine wave cycle?

Definition

360 Degrees

Term

3-7A3:  What type of wave is made up of sine waves of the fundamental frequency and all the odd harmonics?

Definition

Square

Term

3-7A4:  What is the description of a square wave?

Definition

A wave that abruptly changes back and forth between two voltage levels and stays at these levels for equal amounts of time

Term

3-7A5:  What type of wave is made up of sine waves at the fundamental frequency and all the harmonics?

Definition

Sawtooth wave

Term

3-7A6:  What type of wave is characterized by a rise time significantly faster than the fall time (or vice versa)?

Definition

Sawtooth wave

Term

3-8A1:  What is the term used to identify an AC voltage that would cause the same heating in a resistor as a corresponding value of DC voltage?

Definition

Root mean square (RMS)

Term

3-8A2:  What happens to reactive power in a circuit that has both inductors and capacitors?

Definition

It alternates between magnetic and electric fields and is not dissipated

Term

3-8A3:  Halving the cross-sectional area of a conductor will:

Definition

Double the resistance

Term

3-8A4:  Which of the following groups is correct for listing common materials in order of descending conductivity?

Definition

Silver, copper, aluminum, iron and lead

Term

3-8A5:  How do you computer true power (power dissipated in the circuit) in a circuit where AC voltage and current are out of phase?

Definition

Multiply apparent power times the power factor

Term

3-8A6:  Assuming a power source to have a fixed value of internal resistance maximum power will be transferred to the load when:

Definition

The load impedance equals the internal impedance of the source

Term

3-9B1:  What value of series resistor would be needed to obtain a full scale deflection on a 50 microamp DC meter with an applied voltage of 200 volts DC?

Definition

4 megohms

Term

3-9B2:  Which of the following Ohms Law formulas is incorrect?

Definition

I = R / E

Term

3-9B3:  If a current of 2 amperes flows through a 50-ohm resistor, what is the voltage across the resistor?

Definition

100 volts

Term

3-9B4:  If a 100-ohm resistor is connected across 200 volts, what is the current through the resistor?

Definition

2 amperes

Term

3-9B5:  If a current of 3 amperes flows through a resistor connected to 90 volts, what is the resistance?

Definition

30 ohms

Term

3-9B6:  A relay coil has 500 ohms resistance, and operatores on 125 mA.  What value of resistance should be connected in series with it to operate from 110 V DC?

Definition

380 ohms

Term

3-10B1:  What is the peak-to-peak RF voltage on the 50 ohm output of a 100 watt transmitter?

Definition

200 volts

Term

3-10B2:  What is the maximum DC or RMS voltage that may be connected across a 20 watt, 2000 ohm resistor?

Definition

200 volts

Term

3-10B3:  A 500-ohm, 2-watt resistor and a 1500-ohm, 1-watt resistor are connected in parallel.  What is the maximum voltage that can be applied across the parallel circuit without exceeding wattage ratings?

Definition

31.6 volts

Term

3-10B4:  In Figure 3B1, what is the voltage drop across R1?

Definition

5 volts

Term

3-10B5:  In Figure 3B2, what is the voltage drop across R1?

Definition

9 volts

Term

3-10B6:  What is the maximum rated current-carrying capacity of a resistor marked "2000 ohms, 200 watts?"

Definition

0.316 amps

 

Term

3-11B1:  What is the most the actual transmit frequency could differ from a reading of 462,100,000 hertz on a frequency counter with a time base accuracy of +- 0.1 ppm?

Definition

46.21 Hz

Term

3-11B2:  The second harmonic of a 380 kHz frequency is:

Definition

760 kHz

Term

3-11B3:  What is the second harmonic of SSB frequency 4146 kHz?

Definition

8292 kHz

Term

3-11B4:  What is the most the actual transmitter frequency could differ from a reading of 156,000,000 hertz on a frequency counter with a time base accuracy of +- 1.0 ppm?

Definition

156.52 Hz

Term

3-11B5:  What is the most the actual transmitter frequency could differ from a readingof 156,520,000 hertz on a frequency counter with a time base accuracy of +- 10 ppm?

Definition

1565.20 Hz

Term

3-11B6:  What is the most the actual transmitter frequency could differ from a reading of 462,100,000 hertz on a frequency counter with a time base accuracy of +- 1.0 ppm?

Definition
462.1 Hz
Term

3-12B1:  At pi/3 radians, what is the amplitude of a sine-wave having a peak value of 5 volts?

Definition

+4.3 volts

Term

3-12B2:  At 150 degrees, what is the amplitude of a sine-wave having a peak value of 5 volts?

Definition

+2.5 volts

Term

3-12B3:  At 240 degrees, what is the amplitude of a sine-wave having a peak value of 5 volts?

Definition

-4.3 volts

 

Term

3-12B4:  What is the equivalent to the root-mean-square value of an AC voltage?

Definition

The DC voltage causing the same heating in a given resistor as the RMS AC voltage of the same value

Term

3-12B5:  What is the RMS value of a 340-volt peak-to-peak pure sine wave?

Definition

120 volts AC

Term

B-12B6:  Determine the phase relationship between the two signals shown in Figure 3B3.

Definition

B is lagging A by 90 degrees

Term

3-13B1:  What does the power factor equal in an R-L circuit having a 60 degree phase angle between the voltage and the current?

Definition

0.5

Term

3-13B2:  If a resistance to which a constant voltage is applied is halved, what power dissipation will result?

Definition

Double

Term

3-13B3:  746 watts, corresponding to the lifting of 550 pounds at the rate of one-foot-per-second, is the equvalent of how much horsepowe?

Definition

One horsepower

Term

3-13B4:  In a circuit where the AC voltage and current are out of phase, how can the true power be determined?

Definition

By multiplying the apparent power times the power factor

Term

3-13B5:  What does the power factor equal in an R-L circuit having a 45 degree phase angle between the voltage and the current?

Definition

0.707

Term

3-13B6:  What does the power factor equal in an R-L circuit having a 30 degree phase angle between the voltage and the current?

Definition

0.866

Term

3-14B1:  What is the term for the time required for the capacitor in a RC circuit to be charged to 63.2% of the supply voltage?

Definition

One time constant

Term

3-14B2:  What is the meaning of the term "time constant of a RC circuit"?  The time required to charge the capacitor in the circuit to:

Definition

63.2% of the supply voltage

Term

3-14B3:  What is the term for the time required for teh current in a RL circuit to build to 63.2% of the maximum value?

Definition

One time constant

Term

3-14B4:  What is the meaning of the term "time constant of an RL circuit"?  The time required for the:

Definition

Current in the circuit to build up to 63.2% of the maximum value

Term

3-14B5:  After two time constants, the capacitor in a RC circuit is charged to what percentage of the supply voltage?

Definition

86.5%

Term

3-14B6:  After two time constants, the capacitor in a RC circuit is discharged to what percentage of the starting voltage?

Definition

13.5%

Term

3-15B1:  What is the time constant of a circuit having two 220-microfarad capacitors and two 1-megaohm resistors all in parallel?

Definition

220 seconds

Term

3-15B2:  What is the time constant of a circuit having two 100-microfarad capacitors and two 470-kilohm resistors all in series?

Definition

47 seconds

Term

3-15B3:  What is the time constant of a circuit having a 100-microfarad capacitor and a 470-kilohm resistor in series?

Definition

47 seconds

Term

3-15B4:  What is the time constant of a circuit having a 220-microfarad capacitor and a 1-megohm resistor in parallel?

Definition

220 seconds

Term

3-15B5:  What is the time constant of a circuit having two 100-microfarad capacitors and two 470-kilohm resistors all in parallel?

Definition

47 seconds

Term

3-15B6:  What is the time constant of a circuit having two 220-microfarad capacitors and two 1-megohm resistors all in series?

Definition

220 seconds

Term

3-16B1:  What is the impedance of a network composed of a 0.1-microhenry inductor in series with a 20-ohm resistor, at 30 MHz?  Specify your answer in rectangular coordinates?

Definition

20 + j19

 

Term

3-16B2:  In rectangular coordinates, what is the impedance of a network composed of a 0.1-microhenry inductor in series with a 30-ohm resistor, at 5 MHz?

Definition

30 + j3

Term

3-16B3:  In rectangular coordinates, what is the impedance of a network composed of a 10-microhenry inductor in series with a 40-ohm resistor, at 500 MHz?

Definition

4 + j31400

Term

3-16B4:  In rectangular coordinates, what is the impedance of a network composed of a 1.0-millihenry inductor in series with a 200-ohm resisitor, at 30 kHz?

Definition

200 + j188

Term

3-16B5:  In rectangular coordinates, what is the impedance of a network composed of a 0.01-microfarad capacitor in parallel with a 300-ohm resistor, at 50 kHz?

Definition

159 - j150

Term

3-16B6:  In rectangular coordinates, what is the impedance of a network composed of a 0.001-microfarad capacitor in series with a 400-ohm resistor, at 500 kHz?

Definition

400 - j318

Term

3.-17B1:  What is the impedance of a network composed of a 100-picofarad capacitor in parallel with a 4000-ohm resistor, at 500 KHz?  Specify your answer in polar coordinates.

Definition

2490 ohms, | -51.5 degrees

Term

3-17B2:  In polar coordinates, what is the impedance of a network composed of a 100-ohm-reactance inductor in series with a 100-ohm resistor?

Definition

141 ohms, |45 degrees

Term

3-17B3:  In polar coordinates, what is the impedance of a network composed of a 400-ohm reactance capacitor in series with a 300-ohm resistor?

Definition

500 ohms, | -53.1 degrees

Term

3-17B4:  In polar coordinates, what is the impedance of a network composed of a 300-ohm-reactance capacitor, a 600-ohm-reactance inductor, and a 400-ohm resistor, all connected in series?

Definition

500 ohms, |37 degrees

Term

3-17B5:  In polar coordinates, what is the impedance of a network comprised of a 400-ohm-reactance inductor in parallel with a 300-ohm resistor?

Definition

240 ohms, |36.9 degrees

Term

3-17B6:  Using the polar coordinate system, what visual respresentation would you get of a voltage in a sinewave circuit?

Definition

The plot shows the magnitude and phase angle

 

Term

3-18B1:  What is the magnitude of the impedance of a series AC circuit having a resistance of 6 ohms, an inductive reactance of 17 ohms, and zero capacitive reactance?

Definition

18 ohms

Term

3-18B2:  A 1-watt, 10-volt Zener diode with the following characteristics:  Imin = 5 mA; Imax = 95 mA; and Z = 8 ohms, is to be used as part of a voltage regulator in a 20-V power supply.  Approximately what size current-limiting resistor would be used to set its bias to the midpoint of its operating range?

Definition

200 ohms

Term

3-18B3:  Given a power supply with a no load voltage of 12 volts and a full load voltage of 10 volts, what is the percentage of voltage regulation?

Definition

20 %

Term

3-18B4:  What turns ratio does a transformer need in order to match a source impedance of 500 ohms to a load of 10 ohms?

Definition

7.1 to 1

Term

3-18B5:  Given a power supply with a full load voltage of 200 volts and a regulation of 25%, what is the no load voltage?

Definition

250 volts

Term

3-18B6:  What is the conductance (G) of a circuit if 6 amperes of current flows when 12 volts DC is applied?

Definition

0.50 Siemens (mhos)

Term

3-19C1:  What happens to the conductivity of photoconductive material when light shines on it?

Definition

It increases

Term

3-19C2:  What is the photoconductive effect?

Definition

The increased conductivity of an illuminated semiconductor junction

Term

3-19C3:  What does the photoconductive effect in crystalline solids produce a noticeable change in?

Definition

The resistance of the solid

Term

319C4:  What is the description of an optoisolator?

Definition

An LED and a photosensitive device

Term

3-19C5:  What happens to the conductivity of a photosensitive semiconductor junction when it is illuminated?

Definition

The junction resistance decreases

Term

3-19C6:  What is the description of an optocoupler?

Definition

An LED and a phtosensitive device

Term

3-20C1:  What factors determine the capacitance of a capacitor?

Definition

Distance between the plates and the dielectric constant of the material between the plates

Term

3-20C2:  In figure 3C4, if a small variable capacitor were installed in place of the dashed line, it would?

Definition

Decrease parasitic oscillations

Term

3-20C3:  In Figure 3C4:  which component (labeled 1 through 4) is used to provide a signal ground?

Definition

2

Term

3-20C4:  In Figure 3C5, which capacitor (labeled 1 though 4) is being used as a bypass capacitor?

Definition

3

Term

3-20C5:  In Figure 3C5, the 1 uF capacitor is connected to a potentiometer that is used to:

Definition

Adjust tone

Term

3-20C6:  What is the purpose of a coupling capacitor?

Definition

It blocks direct current and passes alternating current

Term

3-1C1:  A capacitor is sometimes placed in series with the primary of a powe transformer to:

Definition

Improve the power factor

Term

3-21C2:  A transformer used to step up its input voltage must have:

Definition

More turns of wire on its secondary than on its primary

Term

3-21C3:  A transformer primary of 2250 turns connected to 120 VAC will develop what voltage across a 500-turn secondary?

Definition

26.7 volts

Term

3-21C4:  What is the ratio of the output frequency to the input frequency of a single-phase full-wave rectifier?

Definition

2:1

Term

3-21C5:  A power transformer has a single primary winding and three secondary windings producig 5.0 volts, 12.6 volts, and 150 volts.  Assuming similar wire sizes, which of the three secondary windings will have the highest measured DC resistance?

Definition

The 150 volt winding

Term

3-21C6:  A power transformer has a primary winding of 200 turns of #24 wire and a secondary winding consisting of 500 turns of the same size wire.  When 20 volts are aplied to the primary winding, the expected secondary voltage will be:

Definition

50 volts

Term

3-22C1:  In a linear electronic voltage regulator:

Definition

The conduction of a control element is varied in direct proportion to the line voltage or load current

Term

3-22C2:  A switching electronic voltage regulator:

Definition

Switches the control device on and off, with the duty cycle proportional to the line or load conditions

Term

3-22C3:  What device is usually used as a stable reference voltage in a linear voltage regulator?

Definition

Zener diode

Term

3-22C4:  In a regulated power supply, what type of component will most likely be used to establish a reference voltage?

Definition

Zener Diode

Term

3-22C5:  A three-terminal regulator:

Definition

Contains a voltage reference, error amplifier, sensing resistors and transistors, and a pass element

 

V.E.S.T.P.

Term

3-22C6:  What is the range of voltage ratings available in Zener diodes?

Definition

2.4 volts to 200 volts and above

Term

3-23C1:  How might two similar SCRs be connected to safely distribute the power load of a circuit?

Definition

In parallel, reverse polarity

Term

3-23C2:  What are the three terminals of a SCR?

Definition

Anode, cathode, and gate

Term

3-23C3:  Which of the following devices acts as two SCRs connected back to back, but facing in opposite directions and sharing a common gate?

Definition

TRIAC

 

(Transistor)

Term

3-23C4:  What is the transistor called that is fabricated as two complementary SCRs in parallel with a common gate terminal?

Definition

TRIAC

Term

3-23C5:  What are the three terminals of a TRIAC?

Definition

Gate, anode 1, and anode 2

Term

3-23C6:  What circuit might contain a SCR?

Definition

A light-dimming circuit

Term

3-24C1:  What is one common use for PIN diodes?

Definition

RF switch

Term

3-24C2:  What is a common use of a hot-carrier diode?

Definition

VHF and UHF mmixers and detectors

Term

3024C3:  Structurally, what are the two main categories of semiconductor diodes?

Definition

Junction and point contact

Term

3-24C4:  What special type of diode is capable of both amplification and ocsillation?

Definition

Tunnel diodes

 

 

(Have negative resistance)

Term

3-24C5:  What type of semiconductor diode varies its internal capacitance as the voltage applied to its terminals varies? 

Definition

Varactor diode

Term

3-24C6:  What is the principal characteristic of a tunnel diode?

Definition

Negative resistance region

 

(Tunnel diode is used for Amplicfication and Oscillation)

Term

3-25C1:  What is the meaning of the term "alpha" with regard to bipolar transistors?  The change of:

Definition

Collector current with respect to emitter current

 

(C.C.E.C.)

Term

3-25C2:  What are the three terminals of a bipolar transistor?

Definition

Base, collector and emitter

Term

3-25C3:  What is the meaning of the term "beta" with regard to bipolar transistors?  The change of:

Definition

Collector current with respect to base current

Term

3-25C4:  What are the elements of a unijunction transistor?

Definition

Base 1, base 2, and emitter

Term

3-25C5:  The beta cutoff frequency of a bipolar transistor is the frequency at which:

Definition

Emitter current gain has decreased to 0.707 of maximum

Term

3-25C6:  What does it mean for a transistor to be fully saturated?

Definition

The collector current is at its maximum value

Term

3-26C1:  A common base amplifier has:

Definition

More voltage gain than common emitter or common collector

Term

3-26C2:  What does it mean for a transistor to be cut off?

Definition

There is no current between emitter and collector

Term

3-26C3:  An emitter-follower amplifier has:

Definition

More current gain than common emitter or common base

Term

3-26C4:  What conditions exits when a transistor is operating in saturation?

Definition

The base-emitter junction and collector-base junction are both forward biased

Term

3-26C5:  For current to flow in an NPN silicon transistor's emitter-collector junction, the base must be:

Definition

At least 0.7 volts positive with respect to the emitter

Term

3-6C6:  When an NPN transistor is operating as a Class A amplifier, the base-emitter junction

Definition

Is forward biased and the collector-base junction is reverse biased

Term

3-27C1:  What type of bias is required for an LED to produce luminescence?

Definition

Forward bias

Term

327C2:  What determines the visible color radiated by an LED junction?

Definition

The materials used to construct the deivce

Term

3-37C4:  What is the approximate operating current of a light-emitting diode?

Definition

20 mA

Term

3-27C4:  What would be the maximum current to safely illuminate a LED?

Definition

20 mA

Term

3-27C5:  An LED facing a photodiode in a light-tight enclosure is commonly known as a/an:

Definition

Optoisolator

Term

3-27C6:  What circuit component must be connected in series to protect an LED?

Definition

Series resistor

Term

3-28C1:  What describes a diode junction that is forward biased?

Definition

It is a low impedance

Term

3-28C2:  Why are special precautions necessary in handling FET and CMOS devices?

Definition

They are susceptible to damage from static charges

Term

2-28C3:  What do the initials CMOS stand for?

Definition

Complementary metal-oxide semiconductor

Term

3-28C4:  What is the piezoelectric effect?

Definition

Mechanical vibration of a crystal by the application of a voltage

Term

2-28C5:  An electrical relay is a:

Definition

Remotely controlled switching device

Term

3-28C6:  In which oscillator circuit would you find a quartz crystal?

Definition

Pierce