# LC Resonance circuit question

#### warp

Joined Jan 20, 2014
18
Hi,
I am trying to make an LC resonant circuit for driving a small resonant transformer and or experimenting with wireless power transfer
.
I have noticed that there are quite a few different possible combinations of L and C that will resonate at the same frequency.

What I am looking for is the combination that will give the most aggressive oscillations in the tank.

Can this be calculated by finding the sum of the L and C impedences and choosing the combination that has the lowest values or perhaps by some other means.

Regards.

#### WBahn

Joined Mar 31, 2012
29,493
What do you define an aggressive oscillation?

For a given resonant frequency the product of L and C must be a constant. The ratio of L and C determine the Q factor. The higher the L the better the Q. But you quickly run into practical limitations regarding realizable component values, particularly if you want to keep the parasitic resistances from rearing their ugly heads.

#### warp

Joined Jan 20, 2014
18
What do you define an aggressive oscillation?

For a given resonant frequency the product of L and C must be a constant. The ratio of L and C determine the Q factor. The higher the L the better the Q. But you quickly run into practical limitations regarding realizable component values, particularly if you want to keep the parasitic resistances from rearing their ugly heads.

What I was meaning by aggressive was the one that allows the most energy to oscillate backward and forward in the tank. Perhaps this means Q. Actually Im not really sure what Q means. The closest I could gather about that was it has a narrow band width for tuning.

Thanks
Regards.

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#### warp

Joined Jan 20, 2014
18
did a quick search and came up with

Let's define what Q really is. Q = 2*Pi*(maximum stored energy)/(energy dissipated per cycle) .

That sounds good. Perhaps what I should have asked is what is the best ratio for a resonant transformer.

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#### crutschow

Joined Mar 14, 2008
33,335
..................
For a given resonant frequency the product of L and C must be a constant. The ratio of L and C determine the Q factor. The higher the L the better the Q. .................
The Q factor is determined by the resistance in the circuit as well as the L and C.
For a series RLC circuit the Q approaches infinity as the resistance goes to zero (Q = ω0L / R).

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