Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
131 Cards in this Set
- Front
- Back
|
What is the purpose of a bypass capacitor
|
removes AC by providing low impedance path to ground
|
|
|
describe an inverting op-amp circuit
|
input and putput signals are 180 degrees out of phase
|
|
|
What type capacitor is used in an op-amp active filter circuit
|
polystyrene
|
|
|
What factors determine sensitivity of a receiver
|
bandwidth, noise figure
|
|
|
What's the prime uses of an op-amp RC active filter?
|
audio filters for receivers
|
|
|
What does the accuracy of a frequency counter depend on
|
internal crystal reference
|
|
|
Whats the function of decade counter digital IC
|
produce 1 output pulse for every 10 input pulses
|
|
|
What is a flip-flop circuit
|
binary sequential logic element with 2 stable states
|
|
|
what type of digital IC is also called a latch
|
a flip flop
|
|
|
what is meant by modulation
|
mixing process where information is imposed on a carrier
|
|
|
why are silicon crystals packed in lead foil for shipping
|
protect against static discharge
|
|
|
what is the SWR of a properly connected transmission line
|
as near to 1:1 as possible
|
|
|
what is the DC resistance in a shunt fed 1/4 wave Marconi antenna
|
zero
|
|
|
where does conductance take place in a waveguide
|
in the walls of the waveguide
|
|
|
what are wave guides?
|
hollow conductors which carry high frequency current
|
|
|
how is the resonant frequency of a hertz antenna lowered
|
place an inductance in series with antenna
|
|
|
whats the effect of adding a capacitor in series to a marconi antenna
|
increases circuit resonant frequency
|
|
|
what is the best standing wave ratio
|
1:1
|
|
|
what is meant by antenna bandwidth
|
frequency range in which an antenna works well
|
|
|
what is the frequency range of aircraft HF communications
|
2.00 MHz to 29.99 MHz
|
|
|
what is the main characteristic of a tunnel diode
|
a negative resistance region
|
|
|
what type diode is capable of amplication and oscillation
|
tunnel diodes
|
|
|
what are the two structural categories of semiconductor diodes
|
junction and point contact
|
|
|
what is the main purpose of a zener diode
|
constant voltage under conditions of changing current
|
|
|
what is the voltage range available in zener diodes
|
2.4 volts to 200 volts
|
|
|
why are power losses low in cavity resonators
|
conducting surfaces are large
|
|
|
how is light emiision from an LED modulated
|
current passing thru the diode
|
|
|
how long does it take a radar pulse to travel a mile
|
6.17 microseconds
|
|
|
whats the effect of corrosion on a parabolic antenna dish
|
poor performance for weak targets
|
|
|
a gunn diode oscillator takes advantage of what effect
|
negative resistance and bulk effect
|
|
|
what is the main characteristic of a varactor diode
|
internal capacitance varies with applied voltage
|
|
|
what is meant by back EMF
|
voltage that opposes the applied EMF
|
|
|
what is the time constant of an RC circuit
|
time required to charge the capacitor to 63.2% of supply voltage
|
|
|
what is the piezoelectric effect
|
mechancial vibration of a crystal by voltage
|
|
|
what are the three general groupings of filters
|
high pass, low pass, band pass
|
|
|
how many gates does a medium scale integrated circuit have
|
10-99 gates
|
|
|
what does slew rate of an op-amp mean
|
output voltage change per microsecond
|
|
|
what fluid makes up liquid crystals in LCD displays
|
nematic fluid
|
|
|
how many JK flip-flops are needed for a MOD-16 ripple counter
|
4
|
|
|
how many RS flip-flops are needed for an 8 bit storage register
|
8
|
|
|
what is the main benefit of a Schottky diode
|
no negative resistance region
|
|
|
what determines the color radiated by an LED
|
material used to construct the device
|
|
|
whats the main advantage to LEDs
|
low power consumption and long life
|
|
|
what bias exists when a transistor operates in saturation
|
base emitter and collector base junctions are both forward bias
|
|
|
what is an enhancement mode FET
|
a FET without a channel
|
|
|
what are the operating modes for field-effect transistors
|
depletion and enhancement mode
|
|
|
what is the impedance of a reverse biased diode junction
|
high impedance to electron flow
|
|
|
what type diode contains no minority carriers in the junction
|
hot-carrier diodes
|
|
|
what logic states do TTL device inputs assume if left open
|
a high logic state
|
|
|
what is the best supply voltage for TTL integrated circuits
|
5.0 volts
|
|
|
what are the major advantages of CMOS over other devices
|
low current consumption
|
|
|
whats the input impedance of a theoretically ideal op-amp
|
infinite
|
|
|
what determines gain of a closed loop op-amp circuit
|
external feedback network
|
|
|
what are the three terminals of a field effect transistor
|
gate, drain, source
|
|
|
what are the two types of junction field-effect transistors
|
n-channel
p-channel |
|
|
what precautions are needed in handling CMOS devices
|
prevention of damage from static charges
|
|
|
what doe the initials CMOS stand for
|
complementary metal oxide semiconductor
|
|
|
what determines bandwidth and response in a crystal lattice filter
|
frequencies of individual crystals
|
|
|
describe a crystal lattice filter
|
narrow bandwidth, steep skits, made of quartz crystals
|
|
|
whats one advantage of ASCII code instead of Baudot code
|
you can transmit upper and lower case text
|
|
|
in pulse width modulation, what parameter does the modulating signal very
|
pulse duration
|
|
|
what is the peak to peak voltage at a common household outlet
|
331 volts
|
|
|
what is the RMs voltage at a common household power outlet
|
117vac
|
|
|
how can you best determine RMS voltage of a complex waveform
|
measure the head effect in a known resistor
|
|
|
whats the the peak voltage of a common household outlet
|
165.5 volts
|
|
|
describe a sawtooth wave
|
straight line rise time faster than fall time
|
|
|
what is the period of a wave
|
time required to complete one cycle
|
|
|
how many degrees are in one complete sine wave cycle
|
360 degrees
|
|
|
whats the purpose of a coupling capacitor
|
blocks direct current, passes alternating current
|
|
|
what occurs if the load is removed from a series DC motor
|
it will accelerate until it flies apart
|
|
|
why do we tin component leads
|
decreases heating time
|
|
|
what tool measures the condition of lead acid batteries
|
hydrometer
|
|
|
what are the best insulations at UHF frequencies
|
teflon and mica
|
|
|
whats the purpose of flux
|
removes and prevents oxide formation
|
|
|
whats the best way to remove insulation from wire
|
thermal stripper
|
|
|
how is solder removed from holes in a printed boards
|
soldering iron and a suction device
|
|
|
3:00 pm US central standard time equals what UTC time (during winter)
|
2100
|
|
|
what solder type is most used when hand soldering electronics
|
60% tin/40% lead
|
|
|
one nautical mile equals how many statute miles
|
1.15 statute miles
|
|
|
what is wetting during a soldering operation
|
blending of solder and copper to form a new alloy
|
|
|
what is the frequency range of UHF
|
.3-3 GHz
|
|
|
what frequency band includes 30-300 MhZ
|
VHF
|
|
|
what determines the magnetic field strength around a conductor
|
amount of current
|
|
|
what factors determine the capacitance of a capacitor
|
area of plates: distance between plates; dielectric constant between plates
|
|
|
what device stores electrical energy in an electrostatic field
|
a capacitor
|
|
|
what is a magnetic field
|
a force set up when current flows thru a conductor
|
|
|
where does most RF current flow in a conductor
|
along its surface
|
|
|
what does the vertical axis of a spectrum analyzer display
|
amplitude
|
|
|
what factors limit the accuracy of a frequency counter
|
time base, speed of logic, stability
|
|
|
whats the wavelength of a signal at 500 MHz
|
60 centimeters
|
|
|
how long does it take a radar signal to travel 1 nautical mile
|
6.2 microseconds
|
|
|
what colors are available in LEDs
|
red green orange yellow
|
|
|
what bias is required for an LED to produce luminescence
|
forward bias
|
|
|
what is normal operating current and voltage of a LED
|
1.7 volts 20 mA
|
|
|
what are the three terminals of a TRIAC
|
gate, anode one, anode two
|
|
|
what are the two stable conditions of an SCR
|
conducting and non conducting
|
|
|
why are silicon and germanium used in semiconductor devices
|
they exhibit both metallic and non-metallic properties
|
|
|
what are the three terminals of an SCR
|
anode, cathode, gate
|
|
|
what are the elements of a unijunction transistor
|
base one, base two, emitter
|
|
|
what does it mean for a transistor to be cut off
|
no current between emitter and collector
|
|
|
What does it mean for a transistor to be fully saturated
|
the collector current is at its maximum value
|
|
|
what is the transitiion region with regard to a transistor
|
area of low charge density around a P-N junction
|
|
|
what is the beta with regard to bipolar transistors
|
change of collector current relative to base current
|
|
|
what is the alpha with regard to bipolar transistors
|
change of collector current relative to emitter current
|
|
|
why type diode is used in RF switches and phase shifting devicess
|
PIN diodes
|
|
|
what are the three terminals of bipolar transistor
|
base, collector, emitter
|
|
|
what diode is made of metal whisker touching a semiconductor die
|
point contact diode
|
|
|
what is the common use of point contact diodes
|
as an RF detector
|
|
|
how are junction diodes rated
|
max forward current and peak inverse voltage
|
|
|
what limits forward current in a junction diode
|
the junction temperature
|
|
|
what is the common use of a hot-carrier diode
|
VHF and UHF mixers and detectors
|
|
|
how much energy does a receiver consume drawing 50 watts for 10 hours
|
1,800,000 joules
|
|
|
how much voltage may be connected across a 20 watt 2000 ohm resistor
|
200 volts
|
|
|
what is the resistance of a 60 watt 117 volt lamp
|
228 ohms
|
|
|
whats the purpose of a shunt resistor on an ammeter
|
increase ampere indicating range
|
|
|
What's the purpose of a multiplier resistor on a voltmeter
|
increase voltage indicating range
|
|
|
what's the voltage of a fully charged lead-acid cell
|
2.06 volts
|
|
|
whats the voltage of a fully charged edison storage cell
|
1.2 volts
|
|
|
the ratio of magnetic flux density to magnetizing force is what concept
|
permeability
|
|
|
if voltage is doubled and resistance tripled, whats the final current
|
2/3rds the original current
|
|
|
how many watts equals one horsepower
|
746 watts
|
|
|
how does the value of an RF current relate to its heating value
|
they are the same
|
|
|
volts x amps x power factor=what?
|
true power
|
|
|
number of turns times current in amps= what unit of measure?
|
gilbert
|
|
|
in what condition will gas be a good conductor
|
when ionized
|
|
|
how will halving a conductor cross section affect resistance
|
resistance will double
|
|
|
what must a transformer have to step up its input voltage
|
more wire turns on its secondary than its primary
|
|
|
how is output voltage of a separately excited AC generator controlled
|
by varying the field current
|
|
|
whats the total voltage when 12 NiCad batteries connect in series?
|
15 volts
|
|
|
why is a crowbar circuit often added to a power supply
|
protects load by activating circuit protection devices
|
|
|
what is the operating voltage of a nickel-cadmium cell
|
approximately 1.25 volts
|
