# resonance frequency of L C

Discussion in 'General Electronics Chat' started by VALKETEER, Mar 14, 2006.

1. ### VALKETEER Thread Starter New Member

Mar 14, 2006
2
0
I have an electronics math problem that is driving me nutz.

10vAC in series with a 10k resistor, a .5mH coil, and a 560pF capacitor. Question is what is the resonance frequency?

Problem:
1
---------------------------------
Fr = 2Pi * square root(.5 mH * 560 pF)

I get (9.5 kH) do you have an idea what step Im missing?

2. ### Papabravo Expert

Feb 24, 2006
10,340
1,850
I don't know where you went wrong, but here is my solution
0.5 mH = 0.5e-3 Henry, and 560 pF = 560e-12 Farad
Code ( (Unknown Language)):
1.
2. Compute the denominator
3. 2 * pi * √ (0.5e-3 * 560e-12) =
4. 6.28 * √ (280e-15) =
5. 6.28 * 529e-9 =
6. 3.324e-6 and
7. Take the reciprocal
8. 1 / 3.324e-6 = 300.77e3 =
9. 301 kHz
10.
11.

3. ### VALKETEER Thread Starter New Member

Mar 14, 2006
2
0
Thanks, I see where I went wrong now.

4. ### hgmjr Moderator

Jan 28, 2005
9,030
214
When I run the numbers through your expresssion, I get 300,774 Hz.

hgmjr