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Subelement B-005

B-005

Section B-005-012

Section B-005-012

Resonance is the condition that exists when:

  • Correct Answer
    inductive reactance and capacitive reactance are equal
  • resistance is equal to the reactance
  • inductive reactance is the only opposition in the circuit
  • the circuit contains no resistance

Resonance is the condition where Inductive Reactance (XL) is equal in value to Capacitive Reactance (XC). For a given Inductance (L, a coil or inductor) and Capacitance (C, a capacitor), resonance happens at one frequency: the resonant frequency. At resonance, the two reactances cancel each other, only resistance is left in the circuit.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

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At resonance, what impedance does a parallel tuned circuit exhibit?

  • Impedance equal to resistance of the circuit
  • Low impedance
  • Correct Answer
    High impedance
  • Impedance equal to reactance of the circuit

Key words: PARALLEL, TUNED. The question refers to Resonance. The one frequency at which Inductive Reactance cancels Capacitive Reactance. In a PARALLEL circuit, Impedance (Z) at resonance is HIGH ( series circuit will be the opposite ). As a memory aid, try to visualize the PARALLEL circuit as a tub or tank, signals get trapped at resonance. Try to visualize the SERIES circuit as a slim tube, signals slip right through at resonance.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

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While the resonant frequency of a tuned circuit is a single frequency, the effect of resonance is significant over a certain range of frequencies. What is this range called?

  • Response curve
  • Shape factor
  • Correct Answer
    Bandwidth
  • Quality factor

The bandwidth of a tuned circuit is the range of frequencies over which its response remains within a certain percentage of its response at the resonant frequency. Bandwidth is related to the Q (quality) factor of the tuned circuit.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

What two components are required to form a tuned circuit?

  • Diode and transistor
  • Resistor and transistor
  • Correct Answer
    Inductor and capacitor
  • Capacitor and resistor

A 'tuned' circuit is a synonym for a 'resonant' circuit. Resonance is the condition where Inductive Reactance (XL) is equal in value to Capacitive Reactance (XC). Inductors and Capacitors alone determine the resonant frequency of a circuit.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

When a parallel coil-capacitor combination is supplied with AC of different frequencies, there will be one frequency where the impedance will be highest. This is the:

  • inductive frequency
  • reactive frequency
  • Correct Answer
    resonant frequency
  • maximum frequency

Key words: COIL, CAPACITOR. A 'tuned' circuit. The question refers to Resonance. The one frequency at which Inductive Reactance cancels Capacitive Reactance. In a PARALLEL circuit, Impedance (Z) at resonance is HIGH ( series circuit will be the opposite ). As a memory aid, try to visualize the PARALLEL circuit as a tub or tank, signals get trapped at resonance. Try to visualize the SERIES circuit as a slim tube, signals slip right through at resonance.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

In a parallel-resonant circuit at resonance, the circuit has:

  • low impedance
  • Correct Answer
    high impedance
  • high mutual inductance
  • low mutual inductance

Key words: PARALLEL, RESONANT. The question refers to Resonance. The one frequency at which Inductive Reactance cancels Capacitive Reactance. In a PARALLEL circuit, Impedance (Z) at resonance is HIGH ( series circuit will be the opposite ). As a memory aid, try to visualize the PARALLEL circuit as a tub or tank, signals get trapped at resonance. Try to visualize the SERIES circuit as a slim tube, signals slip right through at resonance.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

In a series resonant circuit at resonance, the circuit has:

  • high mutual inductance
  • low mutual inductance
  • Correct Answer
    low impedance
  • high impedance

Key words: SERIES, RESONANT. The question refers to Resonance. The one frequency at which Inductive Reactance cancels Capacitive Reactance. In a SERIES circuit, Impedance (Z) at resonance is LOW ( parallel circuit will be the opposite ). If Impedance is low (little total opposition), current will be high. As a memory aid, try to visualize the SERIES circuit as a slim tube, signals slip right through at resonance. Try to visualize the PARALLEL circuit as a tub or tank, signals get trapped at resonance.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

A coil and an air-spaced capacitor are arranged to form a resonant circuit. The resonant frequency will remain the same if we:

  • wind more turns on the coil
  • increase the area of plates in the capacitor
  • insert Mylar sheets between the plates of the capacitor
  • Correct Answer
    add a resistor to the circuit

Resonance is affected exclusively by Inductance (L in henries for inductors) and Capacitance ( C in farads for capacitors ). Capacitance is affected by the area of the plates and the choice of dielectric. Inductance is affected by the number of turns in a coil.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

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Resonant circuits in a receiver are used to:

  • filter direct current
  • adjust voltage levels
  • amplify audio signals
  • Correct Answer
    select the desired signal frequencies

Resonance is about choosing a frequency (or narrow range of frequencies) over others, either to eliminate it or favour it.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

Resonance is the condition that exists when:

  • the circuit contains no resistance
  • inductive reactance is the only opposition in the circuit
  • resistance is equal to the reactance
  • Correct Answer
    inductive reactance and capacitive reactance are equal and opposite in sign

Resonance is the condition where Inductive Reactance (XL) is equal in value to Capacitive Reactance (XC). For a given Inductance (L, a coil or inductor) and Capacitance (C, a capacitor), resonance happens at one frequency: the resonant frequency. At resonance, the two reactances cancel each other, only resistance is left in the circuit.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

What happens to current when a series RLC circuit is tuned to the frequency of the source?

  • It reaches minimum
  • Correct Answer
    It reaches maximum
  • It is limited by inductive reactance
  • It is limited by capacitive reactance

Key words: SERIES, TUNED. The question refers to Resonance. The one frequency at which Inductive Reactance cancels Capacitive Reactance. In a SERIES circuit, Impedance (Z) at resonance is LOW ( parallel circuit will be the opposite ). If Impedance is low (little total opposition), current will be high. As a memory aid, try to visualize the SERIES circuit as a slim tube, signals slip right through at resonance. Try to visualize the PARALLEL circuit as a tub or tank, signals get trapped at resonance.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

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