Finding LRC circuit values when impedance and frequecy is given

[sean87]

Hi all,

I wonder if you can help me with this question:

The given impedances of the series LRC circuit are established at an angular frequency of 2000 rad/s.

Calculate the resonance angular frequency from the given circuit and calculate the current I through the inductor at resonance, given the voltage across the capacitor is 4j mV at resonance.

First, I think that the given impedances are when the frequency is 2000 rad/s , so I tried to find their values when the frequency is 2000 rad/s. Is the approach correct?

Then I remember the formula for finding the critical frequency was as how I wrote it in part 2 of answer. Any ideas if this is correct?

Also, I have no idea how to find the current across L at resonance. What I remember is that in resonance the impedance of C and L are canceling eachother so the given voltage should be the voltage same across the resistor. Can you check please?

[w2aew]

Check your math for the capacitor value calculation...

[sean87]

OK, I missed the 8 in the denominator...the capacitance should be 62.5 uF


My question is, am I even doing the right thing that the question is asking for?

What about current through inductor at resonance? Is it the same current that goes trough the resistor? how to calculate that?

[kxenos]

What is the type to calculate the resonant freq. of a series RLC???

[w2aew]

Your approach is sound.  Calculate the values of L and C with the info given.  Use that to calculate resonant frequency.  It is a series circuit, so the current is identical through each of the components.