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?
- 35 turns
- 13 turns
- 79 turns
- 141 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?
- Polystyrene and polyethylene
- Ferrite and brass
- Teflon and Delrin
- Cobalt and aluminum
What is one reason for using ferrite cores rather than powdered-iron in an inductor?
- Ferrite toroids generally have lower initial permeability
- Ferrite toroids generally have better temperature stability
- Ferrite toroids generally require fewer turns to produce a given inductance value
- Ferrite toroids are easier to use with surface mount technology
What core material property determines the inductance of a toroidal inductor?
- Thermal impedance
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 a few kHz to no more than 30 MHz
- From less than 20 Hz to approximately 300 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 have greater initial permeability
- Powdered-iron cores generally maintain their characteristics at higher currents
- 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?
- Electrolytic capacitors
- Butterworth filters
- Ferrite beads
- Steel-core toroids
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?
- 2 turns
- 4 turns
- 43 turns
- 229 turns
What is the definition of saturation in a ferrite core inductor?
- The inductor windings are over coupled
- The inductor's voltage rating is exceeded causing a flashover
- The ability of the inductor's core to store magnetic energy has been exceeded
- Adjacent inductors become over-coupled
What is the primary cause of inductor self-resonance?
- Inter-turn capacitance
- The skin effect
- Inductive kickback
- 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?
- Magnetizing current
- Direct current
- Excitation current
- Stabilizing current
What is the common name for a capacitor connected across a transformer secondary that is used to absorb transient voltage spikes?
- Clipper capacitor
- Trimmer capacitor
- Feedback capacitor
- Snubber capacitor
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