how a self-resonating flywheel is a near-perfect analogy for a self-resonating coil

Dear MileHigh.

On the contrary, I don't think there was a point to be missed.

Your flywheel ceased to be a " Flywheel " the moment it stopped rotating. IMO your analogy is more akin to a mechanical oscillator.

From my perspective any flywheel that's rotating at a fixed speed ( doesn't matter what speed ) is resonant. My reasoning ? The flywheel, once up to speed requires far less energy than it took to get there.

Kind regards,  Graham.

Sure I would be happy to explain this to you again.  Typically high-frequency voltage travels down the single wire.  However, with no current flow you cannot transfer any AC power into the load.  So the question is how do you get current to flow when there is no apparent current loop in the circuit?  As we know, for current to flow, there must be a loop.

We also know that there exists so-called "stray" (a.k.a. parasitic) capacitance everywhere.  A capacitor is just two conducting plates separated by a distance.  Let's look at a trivial example.  Suppose you are outside in your back yard.  Let's say there is an insulating plastic lawn chair that you are sitting in and your feet are not touching the ground.  We know that the ground is conductive and there is always some moisture in the ground that helps it become more conductive.  We also know the human body is basically salty water, and so the human body is conductive.

Therefore, when you sit on an insulating plastic chair in your back yard with your feet not touching the ground we can say that there is a measurable capacitance between your body and the ground.  It may be very small, perhaps 100 pF, but it is there and it is measurable.  In reality, there is stray or parasitic capacitance everywhere.

It is this stray capacitance that allows AC current to conduct in a current loop that allows for so-called "single wire power transmission."

Here is a typical circuit current loop:

<earth ground> ---> <stray capacitor #1> ---> <high frequency AC signal generator> ---> <load> ---> <stray capacitor #2> ---> <back to earth ground>

When you do a "single wire power transmission" experiment there are typically two "invisible" stray capacitors that allow AC current to flow.  Therefore the load sees both voltage and current and therefore AC power gets transferred into the load.  Small neon lights and LEDs require very little power to light up and that's why you often see them lit in experiments like this.

This is a fairly straightforward concept that should be understood by people interested in experimenting with electronics.

I'll just leave this here for anyone who cares:


Gyroscopic Primer by Prof Eric Laithwaite


Dave

Thanks, gread vid. watched it last night.  interesting what a gyroscope does with weight.
but i cant see an anology with a oscilating bifilar coil.  its not alternating, it looks more like Dc. constant velocity (and slowing down).
still the current is pulsed through a spiral coil inward or outward.