Parallel resonant circuit

Thread Starter

Borne

Joined Jan 7, 2021
6
Which of the following statements is true of a parallel resonant circuit?
  • At resonance, the circulating current within the tank is greater than the line current.
  • At resonance the line current is maximum. (Wrong since this would be for a series circuit)
  • The voltage across the capacitor or coil may be higher than the applied voltage.
  • At resonance the impedance of the tank is found by the formula Z = Q / XL

I've figured out that the second one is not it but struggling to be certain of the correct answer.
 

MrAl

Joined Jun 17, 2014
8,241
Which of the following statements is true of a parallel resonant circuit?
  • At resonance, the circulating current within the tank is greater than the line current.
  • At resonance the line current is maximum. (Wrong since this would be for a series circuit)
  • The voltage across the capacitor or coil may be higher than the applied voltage.
  • At resonance the impedance of the tank is found by the formula Z = Q / XL

I've figured out that the second one is not it but struggling to be certain of the correct answer.
You are right about the second one because of the impedance of LC in parallel.

When i run across questions like this i like to set up a circuit and analyze it for the various quantities being asked for. You should try that.
Calculate the inductor current iL and cap current iC then compare the two.
Figure out how the voltage of the LC pair can be higher than the applied source voltage. Add a resistor in series and try again.
Calculate the Q and inductive reactance to figure out the last one.

LATER:
Another interesting experiment is to equate the inductor current to the capacitor current and see if you can come up with the formula for the LC resonant frequency.
 
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