Recent content by Leo Freeman

I get it now.:cry: Thank you for explaining this so patiently! So the fact that the inner mesh plates are actively charged by an external voltage, it still doesn't have any effect on the capacitance of the outer plates? How about using an electret as a dielectric? Well, if Nature is not going...

Thank you for this info. I can see how a single mesh would make two capacitors in series, but what about two meshes? Two meshes forming an inner capacitor, with a polarity that's the reverse of that of the outer plates? Discrete capacitors in circuits have their own self-contained electric...

Thanks for the tip about the gyrator! This is turning into a learning experience for a non EE like me. I'm not looking so much for a variable capacitor, but to simulate a "super-dielectric", using applied potentials to force a capacitor soak up a huge amount of charge, by canceling any field...

Is it possible that the dielectric may not the the thing which really changes the capacitance? If an air capacitor had another inner set of plates made of mesh, like this: wouldn't the inner electric field modify the outer plate field (and hence, vary the capacitance) just like a dielectric...

Thanks for all this. It has illuminated the murky world of patent law. My take-home message in all of this is that an inventor doesn't have to prove his invention actually works in order to get a Patent!

It certainly doesn't look workable by relying on some property of the dielectric. I wonder what was the point of patenting the device before a suitable material could be found?

Thank you again for that information. Leeper says in the patent: "It is known that altering the electromagnetic field within or surrounding a dielectric material will alter the relative permittivity of the dielectric. It is upon this principle that the present invention is based." It sounds...

Thank you very much, Jim, for that info! Can we assume, then, that this device actually works? If so, why do people waste time with varicaps and cumbersome mechanically-variable capacitors? How come this important device is not more widely known to the electronics community? (I hope there's a...

Thanks for that. Yes, at first I was amused by Paul's account of the patenting of the FET, but now I'm angry; that sort of "patent squatting" on vague half-baked ideas should not be allowed. It's corruption, I say.

Wow, That was a long-term gamble! Do you think Leeder is trying the same trick, just with capacitors? I noticed he said in the patent: "As a practical matter, there are no limitations as to the size or geometry of the capacitor of the present invention or the type of dielectric material used."...

Yes, I just read about varicaps. They have two leads only, though, and apparently limited to the pFarad range. This patent, however, seems to describe a triode-like device, and not using semiconductors.

Thanks for your reply. It is a bit of a mystery; no-one seems to have heard of this idea, but the patent definitely claims it works. I can't imagine why someone would spend the money patent a fake device?

Is the "Voltage variable capacitor" described in patent US 20070242410 A1 a commercially available component? Has anyone heard of this method of changing the dielectric constant using a biasing voltage? It has been nearly 13 years since the patent was filed, but I've never heard of it. It would...