# One more question on Tesla coils :)

1. Nov 29, 2016

### fog37

Dear Forum,
I have recently tried to understand how a Tesla coil works.
A Tesla coil seems very similar to a regular transformer. Based on my understanding, a transformer is fundamentally composed of two inductors (with possibly a different number of windings) interlinked by an iron core. A transformer has many uses. Once of them is to step up or step down an input AC voltage (vice versa for the AC current).

Tesla coils, which can wirelessly turn on nearly fluorescent lights, are said to be resonant transformers.
In what sense are ordinary transformers not resonant? The word "resonant" brings to mind an LC or RLC circuit which has a resonant angular frequency $\omega_0= 1/ \sqrt{LC}$. So a transformer surely has an inductance L in virtue of the fact that it is composed of two inductors.
I guess regular transformers, which seem to work any any frequency $f$, actually work better at a certain frequency, the resonant frequency?

Thanks!

2. Nov 29, 2016

### Staff: Mentor

3. Nov 29, 2016

### sophiecentaur

I would avoid getting too taken up with all the Tesla culture. The basics of Maxwells Equations, Antenna and RF Propagation theory are very well proven and have been successfully used for more than a hundred years. Tesla's ideas are far from the mainstream theories. This appeals to some people but it should be born in mind that Tesla was a lot better at hand waving ideas and flowery language than providing mathematical proof or repeatable measurements. Personally, I prefer to stick with something that actually works every day and all over the World, rather than going for the Magic of the Tesla scene.
PS He did, of course, successfully champion AC electrical power distribution. So he was not all bad.