2016-E6D: Toroidal and Solenoidal Inductors: permeability, core material, selecting, winding; transformers; Piezoelectric devices
How many turns will be required to produce a 5-microhenry inductor using a powdered-iron toroidal core that has an inductance index (A L) value of 40 microhenrys/100 turns?
What is the equivalent circuit of a quartz crystal?
Motional capacitance, motional inductance, and loss resistance in series, all in parallel with a shunt capacitor representing electrode and stray capacitance
Motional capacitance, motional inductance, loss resistance, and a capacitor representing electrode and stray capacitance all in parallel
Motional capacitance, motional inductance, loss resistance, and a capacitor representing electrode and stray capacitance all in series
Motional inductance and loss resistance in series, paralleled with motional capacitance and a capacitor representing electrode and stray capacitance
Which of the following is an aspect of the piezoelectric effect?
Mechanical deformation of material by the application of a voltage
Mechanical deformation of material by the application of a magnetic field
Generation of electrical energy in the presence of light
Increased conductivity in the presence of light
Which materials are commonly used as a slug core in a variable inductor?
Ferrite and brass
Polystyrene and polyethylene
Teflon and Delrin
Cobalt and aluminum
What is one reason for using ferrite cores rather than powdered-iron in an inductor?
Ferrite toroids generally require fewer turns to produce a given inductance value
Ferrite toroids generally have lower initial permeability
Ferrite toroids generally have better temperature stability
Ferrite toroids are easier to use with surface mount technology
What core material property determines the inductance of a toroidal inductor?
What is the usable frequency range of inductors that use toroidal cores, assuming a correct selection of core material for the frequency being used?
From less than 20 Hz to approximately 300 MHz
From a few kHz to no more than 30 MHz
From approximately 10 Hz to no more than 3000 kHz
From about 100 kHz to at least 1000 GHz
What is one reason for using powdered-iron cores rather than ferrite cores in an inductor?
Powdered-iron cores generally maintain their characteristics at higher currents
Powdered-iron cores generally have greater initial permeability
Powdered-iron cores generally require fewer turns to produce a given inductance
Powdered-iron cores use smaller diameter wire for the same inductance
What devices are commonly used as VHF and UHF parasitic suppressors at the input and output terminals of a transistor HF amplifier?
What is a primary advantage of using a toroidal core instead of a solenoidal core in an inductor?
Toroidal cores confine most of the magnetic field within the core material
Toroidal cores make it easier to couple the magnetic energy into other components
Toroidal cores exhibit greater hysteresis
Toroidal cores have lower Q characteristics
How many turns will be required to produce a 1-mH inductor using a core that has an inductance index (A L) value of 523 millihenrys/1000 turns?
What is the definition of saturation in a ferrite core inductor?
The ability of the inductor's core to store magnetic energy has been exceeded
The inductor windings are over coupled
The inductor's voltage rating is exceeded causing a flashover
Adjacent inductors become over-coupled
What is the primary cause of inductor self-resonance?
The skin effect
Non-linear core hysteresis
Which type of slug material decreases inductance when inserted into a coil?
What is current in the primary winding of a transformer called if no load is attached to the secondary?
What is the common name for a capacitor connected across a transformer secondary that is used to absorb transient voltage spikes?
Why should core saturation of a conventional impedance matching transformer be avoided?
Harmonics and distortion could result
Magnetic flux would increase with frequency
RF susceptance would increase
Temporary changes of the core permeability could result
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