Ekectronic Devices 6- Comms To Linear Digital IC Flashcards
An AM demodulator can be implemented with a linear multiplier followed by a ________ filter.
low-pass
high-pass
band-pass
band-stop
low-pass
The intermediate frequency in a standard AM receiver is
455 Hz.
455 kHz.
4.55 MHz.
none of the above
455 kHz.
In order for a light ray to propagate along a fiber-optic cable, what must the relationship be between the angle of incidence and the critical angle?
θi > θc
θi < θc
θi = θc
none of the above
θi > θc
Light may be propagated along a fiber-optic cable in which of the following modes?
multimode step index
single-mode step index
multimode graded index
all of the above
all of the above
In AM, the carrier is changed by a modulating signal. What parameter of the carrier is changed?
amplitude
frequency
pulse width
phase
amplitude
The output spectrum of a ________ modulator includes upper-side and lower-side frequencies and the carrier frequency.
balanced
standard amplitude
none of the above
standard amplitude
Amplitude modulation is a ________ process.
multiplication
division
sum/difference
multiplication
What does VCO stand for?
Visually-Controlled Organization
Voltage-Controlled Oscillator
Voltage-Centered Oscilloscope
Voltage-Controlled Oscillator
A phase-locked loop (PLL) is a feedback circuit consisting of a
phase detector.
low-pass filter.
VCO.
all of the above
all of the above
If a 1 MHz carrier is amplitude modulated with a 5 kHz audio signal, the upper-side frequency is ________ kHz.
1005
1000
995
none of the above
1005
Which of the following areas is (are) an application of infrared-emitting diodes?
Intrusion alarms
Shaft encoders
Paper-tape readers
All of the above
All of the above
Schottky diodes are very effective at frequencies approaching ________.
20 GHz
10 MHz
100 MHz
1 MHz
A
What is the voltage drop across Schottky diodes?
0 V to 0.2 V
0.7 V to 0.8 V
0.8 V to 1.0 V
1.0 V to 1.5 V
0 V to 0.2 V
In which region is the operating point stable in tunnel diodes?
Negative-resistance
Positive-resistance
Both negative- and positive-resistance
Neither negative- nor positive-resistance
Positive-resistance
What is the range of the varying capacitor CT in varactor diodes?
0 pF to 5 pF
2 pF to 10 pF
2 F to 100 F
2 pF to 100 pF
2 pF to 100 pF
What is the maximum temperature limit for liquid-crystal displays (LCDs)?
10ºC
30ºC
60ºC
100ºC
60ºC
Which of the following diodes is limited to the reverse-bias region in its region of operation?
Schottky
Tunnel
Photodiode
Rectifier
Photodiode
The majority of power diodes are constructed using ________.
molybdenum
platinum
tungsten
silicon
silicon
Which of the following is (are) diodes?
Schottky
Varactor
Tunnel
All of the above
All of the above
What is the limit of peak current IP in tunnel diodes?
A few microamperes to several hundred amperes
A few microamperes to several amperes
A few microamperes to several milliamperes
A few microamperes to several hundred microamperes
A few microamperes to several hundred amperes
What is the response time of LCDs?
Less than 100 ns
50 ms
100 ms to 300 ms
400 ms
100 ms to 300 ms
What is the typical level of change in resistance per degree change in temperature?
1% to 2%
3% to 5%
7% to 10%
10% to 25%
3% to 5%
What is the maximum peak voltage for tunnel diodes?
50 mV
100 mV
250 mV
600 mV
600 mV
Which of the following semiconductor materials is (are) used for manufacturing solar cells?
Gallium arsenide
Indium arsenide
Cadmium sulfide
All of the above
All of the above
Which of the following semiconductor materials is (are) used in the manufacturing of tunnel diodes?
Germanium
Gallium
Both germanium and gallium arsenide
Silicon
Both germanium and gallium arsenide
What is the power density received from the sun at sea level?
10 mW/cm2
100 mW/cm2
500 mW/cm2
1 W/cm2
100 mW/cm2
The varicap diode has a transition capacitance sensitive to the applied reverse-bias potential that is a maximum at zero volts and decreases ________ with increasing reverse-bias potentials.
logarithmically
parabolically
exponentially
exponentially
For a 50-A unit, the PIV of the Schottky is about ________ compared to 150 V for the p-n junction variety.
25
50
75
100
50
What metal(s) is(are) used in the construction of Schottky diodes?
Molybdenum
Platinum
Tungsten
Silicon
Any of the above
Any of the above
Which of the following metals is (are) used in the fabrication of Schottky diodes?
Molybdenum
Platinum
Tungsten
All of the above
All of the above
What is the resistance of thermistors at boiling temperature (100ºC)?
5 k
1 k
100
1
100
Which of the following areas is (are) applications of varactor diodes?
FM modulators
Automatic-frequency control devices
Adjustable bandpass filters
All of the above
All of the above
Which of the following materials is (are) used in the manufacturing of thermistors?
Ge
Si
A mixture of oxides of cobalt, nickel, strontium, or manganese
All of the above
All of the above
What is the ratio IP / IV for gallium arsenide?
1:1
5:1
10:1
20:1
20:1
What is the response time of light-emitting diodes (LEDs)?
Less than 100 ns
50 ms
100 ms to 300 ms
400 ms
Less than 100 ns
What type of temperature coefficient do thermistors have?
Positive
Negative
Either positive or negative
None of the above
Either positive or negative