With reference to the circuit on attached. If we don't know the value of L, before we go to measure it, Is there any ways to calculate for C' without knowing the value of L? I believe this story would be involve to the frequency-domain. Therefore, if we have the data of frequency response, such as the point where frequency starts to rise or cut-off frequency, can we use it instead?

 

Hello and welcome.

What is the goal, is it to make the circuit look purely resistive?

 

With reference to the circuit on attached. If we don't know the value of L, before we go to measure it, Is there any ways to calculate for C' without knowing the value of L? I believe this story would be involve to the frequency-domain. Therefore, if we have the data of frequency response, such as the point where frequency starts to rise or cut-off frequency, can we use it instead?

What would you base your calculation of C' on?

If you have the data of the frequency response of what? The loudspeaker by itself? The whole thing (using what value of C'?)

 

What would you base your calculation of C' on?

If you have the data of the frequency response of what? The loudspeaker by itself? The whole thing (using what value of C'?)

What the heck are you doing?
This isnt the homework section!

Is there some reason you dont want to actually answer this question?

 

Hello and welcome.

What is the goal, is it to make the circuit look purely resistive?

Yes, to make the circuit look purely resistive and to flatten the rising impedance at higher frequency due to voilce coil's self-inductance of loudspeaker.

 

What would you base your calculation of C' on?

If you have the data of the frequency response of what? The loudspeaker by itself? The whole thing (using what value of C'?)

The basis of calculation of C' referred to the formula in the attached: C' = L/R^2. Also, I'm searching for its derivation. If anyone know it, please help to educate me.

The frequency response is of loudspeaker.

 

Yes, to make the circuit look purely resistive and to flatten the rising impedance at higher frequency due to voilce coil's self-inductance of loudspeaker.

Ok then you have to be able to apply an AC voltage and measure the AC current.
You can then use this:
L=sqrt(v^2-i^2*Re^2)/(2*pi*f*i)

where
'v' is the applied AC voltage at frequency 'f' in Hertz,
'i' is the measured AC current,
Re is the directly measured DC voltage of the speaker,
pi=3.14169...

You may want to measure and calculate over several values of voltage and form a consensus of what L should be for the best range.

 

What the heck are you doing?
This isnt the homework section!

Is there some reason you dont want to actually answer this question?

Why did you ask what the goal was? Could it be, perhaps, that you weren't sure what the goal was and wanted clarification?

Well, I'm not sure what the calculation of C' is supposed to be based on if it is being done before anything is being made to determine L. I also wanted clarification as to just what the frequency response data was for.

Sorry if trying to get a better understanding of what the TS is doing and what they have to work with so offends you; I didn't realize that you are the only one that gets to ask for clarification on anything. So have fun. I was going to walk through the derivation of where the formula for C comes from, but I don't want to further offend you.

 

Why did you ask what the goal was? Could it be, perhaps, that you weren't sure what the goal was and wanted clarification?

Well, I'm not sure what the calculation of C' is supposed to be based on if it is being done before anything is being made to determine L. I also wanted clarification as to just what the frequency response data was for.

Sorry if trying to get a better understanding of what the TS is doing and what they have to work with so offends you; I didn't realize that you are the only one that gets to ask for clarification on anything. So have fun. I was going to walk through the derivation of where the formula for C comes from, but I don't want to further offend you.

Oh ok sorry i guess i read into it differently
It sounded like you didnt want to give too much away and make the OP think for themself which is what we usually do in the Homework section.

You can go over the derivation if you like and maybe take a look at the calculation for C. It appears that the formula i see on the web says C should be 1.25 times L/Re^2 but instead of what seems like an arbitrary 1.25 i think 1.00 works better. I am not sure if they want a purely resistive load though.