wireless transfer of energy?

Question

how can I resonate a coil of wire at 10Mhz or any other given frequency.
I want to use it in the wireless transfer of energy for my science fair project.
Iam in 11th year. What do you think. Is it difficult for me?

Answer 1

It's somewhat difficult, but would be easier if you have access to an electronic workbench. You need to have an oscillator which will drive one of the coils. And it would be a big help if it's a variable-frequency oscillator so you can tune your circuits. Each coil (inductance L) should have a capacitor (C) in parallel to make a resonant circuit. It would help, but is not absolutely necessary, to start with identical coils and capacitors. Use the formula F = 1/(2*pi*sqrt(L*C)) to select values for L and C if you want a specific frequency, or if you want to know the frequency given L and C. See the ref. for the theory of L-C resonance.
I would suggest a frequency that is in the kHz range, not mHz. It's less subject to misreading of voltage and less dependent on well-trimmed wiring. Adjust one or the other C with additional small paralleled capacitors as needed so the two L-C circuits resonate at the same frequency. You can find resonance as the frequency where the voltage across the L-C circuit reaches a peak. When you set up the system, the oscillator will be driving one L-C circuit, and next to that will be the other L-C circuit connected to an AC voltmeter, with the two coils arranged so their axes are roughly aligned. There's a lot I've had to leave out of this quickie answer, such as exactly how to drive the L-C with the oscillator, and ensuring that the L and C values are not grossly mismatched. You should try to get some in-person help if possible.

Answer 2

If you just want to transfer enegery, then use two coils that have the same number of turns and that are the same size. They should resonate.

If you need a specific frequency, then look up how to make a radio, because the coil is used to tune the radio to a specific frequency.