Why this cable on neon sign transformer?

[J_Nichols]

2)
Not. You can have magnetic coupling even when two inductive elements do not have the same inductance. Look at a standard transformer--One winding has a higher inductance than the other (unless it's just an isolation transformer, but let's not get into that right now), but they are still magnetically coupled.

Resonance does not require two coils. Resonance is when a capacitor and an inductor oscillate at their own natural frequency. Resonance is a characteristic of a capacitor and an inductor, not of two inductors.

This is a non sense question, but imagine that we have a circuit with 2 transformers with the outputs not connected to any load. Can be L1 and L2 in some kind of resonance?
In this configuration there is a AC source and there are 2 transformers with only the primary connected to the circuit.

 

[DerStrom8]

This is a non sense question, but imagine that we have a circuit with 2 transformers with the outputs not connected to any load. Can be L1 and L2 in some kind of resonance?
In this configuration there is a AC source and there are 2 transformers with only the primary connected to the circuit.

You need to define L1 and L2. I'm really not understanding the question though, I'm afraid.....

 

[J_Nichols]

You need to define L1 and L2. I'm really not understanding the question though, I'm afraid.....

Something like the next picture.

But it's possible that I have confused the primary of a transformer with a coil + core. What means the coil and the line? A tunable inductor?