75 lines
4.0 KiB
Markdown
75 lines
4.0 KiB
Markdown
E6D Inductors and piezoelectricity: permeability, core material and configuration; transformers; piezoelectric devices
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- [[E6D01]] (C)
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What is piezoelectricity? #card
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- [[A.]] The ability of materials to generate electromagnetic waves of a certain frequency when voltage is applied
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- [[B.]] A characteristic of materials that have an index of refraction which depends on the polarization of the electromagnetic wave passing through it
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- [[C.]] A characteristic of materials that generate a voltage when stressed and that flex when a voltage is applied
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- [[D.]] The ability of materials to generate voltage when an electromagnetic wave of a certain frequency is applied
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- [[E6D02]] (A)
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What is the equivalent circuit of a quartz crystal? #card
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- [[A.]] Series RLC in parallel with a shunt C representing electrode and stray capacitance
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- [[B.]] Parallel RLC, where C is the parallel combination of resonance capacitance of the crystal and electrode and stray capacitance
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- [[C.]] Series RLC, where C is the parallel combination of resonance capacitance of the crystal and electrode and stray capacitance
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- [[D.]] Parallel RLC, where C is the series combination of resonance capacitance of the crystal and electrode and stray capacitance
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- [[E6D03]] (A)
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Which of the following is an aspect of the piezoelectric effect? #card
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- [[A.]] Mechanical deformation of material due to the application of a voltage
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- [[B.]] Mechanical deformation of material due to the application of a magnetic field
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- [[C.]] Generation of electrical energy in the presence of light
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- [[D.]] Increased conductivity in the presence of light
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- [[E6D04]] (B)
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Why are cores of inductors and transformers sometimes constructed of thin layers? #card
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- [[A.]] To simplify assembly during manufacturing
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- [[B.]] To reduce power loss from eddy currents in the core
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- [[C.]] To increase the cutoff frequency by reducing capacitance
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- [[D.]] To save cost by reducing the amount of magnetic material
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- [[E6D05]] (C)
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How do ferrite and powdered iron compare for use in an inductor core? #card
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- [[A.]] Ferrite cores generally have lower initial permeability
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- [[B.]] Ferrite cores generally have better temperature stability
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- [[C.]] Ferrite cores generally require fewer turns to produce a given inductance value
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- [[D.]] Ferrite cores are easier to use with surface-mount technology
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- [[E6D06]] (D)
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What core material property determines the inductance of an inductor? #card
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- [[A.]] Permittivity
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- [[B.]] Resistance
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- [[C.]] Reactivity
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- [[D.]] Permeability
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- [[E6D07]] (D)
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What is the current that flows in the primary winding of a transformer when there is no load on the secondary winding? #card
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- [[A.]] Stabilizing current
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- [[B.]] Direct current
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- [[C.]] Excitation current
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- [[D.]] Magnetizing current
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- [[E6D08]] (B)
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Which of the following materials has the highest temperature stability of its magnetic characteristics? #card
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- [[A.]] Brass
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- [[B.]] Powdered iron
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- [[C.]] Ferrite
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- [[D.]] Aluminum
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- [[E6D09]] (C)
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What devices are commonly used as VHF and UHF parasitic suppressors at the input and output terminals of a transistor HF amplifier? #card
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- [[A.]] Electrolytic capacitors
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- [[B.]] Butterworth filters
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- [[C.]] Ferrite beads
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- [[D.]] Steel-core toroids
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- [[E6D10]] (A)
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What is a primary advantage of using a toroidal core instead of a solenoidal core in an inductor? #card
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- [[A.]] Toroidal cores confine most of the magnetic field within the core material
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- [[B.]] Toroidal cores make it easier to couple the magnetic energy into other components
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- [[C.]] Toroidal cores exhibit greater hysteresis
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- [[D.]] Toroidal cores have lower Q characteristics
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- [[E6D11]] (B)
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Which type of core material decreases inductance when inserted into a coil? #card
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- [[A.]] Ceramic
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- [[B.]] Brass
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- [[C.]] Ferrite
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- [[D.]] Aluminum
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- [[E6D12]] (C)
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What causes inductor saturation? #card
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- [[A.]] Operation at too high a frequency
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- [[B.]] Selecting a core with low permeability
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- [[C.]] Operation at excessive magnetic flux
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- [[D.]] Selecting a core with excessive permittivity
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