# Tank Circuit Equation

Discussion in 'Math' started by The Lightning Stalker, Jul 24, 2008.

1. ### The Lightning Stalker Thread Starter New Member

Jul 24, 2008
2
0
Hello. I'm trying to isolate L to find out the needed inductance based on resonance frequency and capacitance. I can't remember how to get rid of the square root when it's on the bottom of a fraction.

Robert

2. ### Wendy Moderator

Mar 24, 2008
20,772
2,540
You square both sides.

3. ### The Lightning Stalker Thread Starter New Member

Jul 24, 2008
2
0
Okay, but what parts do I square, I'm not sure. Also I have no idea how to get rid of the 1 on top of the fraction. It's been a long time since I had to do an equation like this.

Thank you,
Robert

4. ### Mark44 Well-Known Member

Nov 26, 2007
626
1
I'm assuming you are trying to solve an equation. As Bill said, you can square both sides of the equation, which will get rid of the radical in the denominator. We can't give you any more advice, since we don't know what the equation you're working with is. If you post it, we can give you some more help.

5. ### PinkDalek Member

Dec 18, 2005
10
0
Hi Robert, I've hand drawn the formulas for you, I believe this is probably what you want, but please take care when you use them as it's very easy to make a mistake, I would suggest you do a practice calculation using values for L & C and find the frequency and then apply the frequency value to the other formulas with either known value of L or C and when you get the values correct you will know you've used the correct method of working out.

All the best,
Lorraine

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Last edited: Jul 25, 2008
6. ### PinkDalek Member

Dec 18, 2005
10
0
With regard to my previous post it has occured to me that non members or guests cannot view attached images, so here's a simple text version of the formulas for our guests.

F=1/(2*PI*sqrt(L*C))

L=1/(4*PI*PI*F*F*C)

C=1/(4*PI*PI*F*F*L)

Where F=frequency in Hertz, L=inductance in Henries, C=capacitance in Farads and PI=$\pi$ which is 3.1415927 correct to 7 decimal places.

I hope that helps.

best wishes,
Lorraine

Last edited: Jul 27, 2008