Lorentz force questions

[broli]

Hi GB, even before seeing this article I was playing around with different kind of setups in my mind. I always have and still believe that the homopolar motor/generator is one of the least researched aspects in physics/relativity while there's still much to discover. Following in the footsteps of people like Stefan Marinov, J. Guala-Valverde, Bruce DePalma, Robert J Distinti...and many more, I decided to continue where they left off.

Especially the "electrometer" probe mentioned in that article you show is something I've been thinking about for a while. That is, a way to perform truly "single piece" voltage measurements without having to close the loop which would end up raising the endless question as to where the voltage is truly generated. The open probe circuit can actually be very easily be constructed, here's such circuit..

http://www.amasci.com/emotor/chargdet.html

My only question is about sensitivity. however this is also mentioned

Regular foil-leaf electroscopes deal with electrostatic potentials in the range of many hundreds or thousands of volts. The above device can detect one volt. Its sensitivity is ridiculously high.

[gravityblock]

Broli,

The electrometer you referenced is a great find.  The 1 volt is doable, but out of curiosity, is there a way of cheating by placing a small electret in the vicinity of the electrometer at a distance which would be just shy of turning the LED on/off?  Couldn't we then detect a smaller voltage in the millivolt range during our experiments?  I'm interested in the half moon magnet too.

GB

[broli]

Broli,

The electrometer you referenced is a great find.  The 1 volt is doable, but out of curiosity, is there a way of cheating by placing a small electret in the vicinity of the electrometer at a distance which would be just shy of turning the LED on/off?  Couldn't we then detect a smaller voltage in the millivolt range during our experiments?  I'm interested in the half moon magnet too.

GB

I don't think you need to go that far, you could just cascade a few of those FETs to amplify the signal further. However another issue to note is that most neo magnets have a metallic coating which is conductive. When you spin this with the magnet it will induce a voltage, per homopolar generator rules, and this voltage will thus polarize the coating. The question that then will arise is are you measuring, in the probe, the induced voltage applied by homopolar rules or the induced voltage due to electrostatic induction of the coating. However this can easily be resolved by using a plastic/rubber coated magnet.

[gravityblock]

I don't think you need to go that far, you could just cascade a few of those FETs to amplify the signal further. However another issue to note is that most neo magnets have a metallic coating which is conductive. When you spin this with the magnet it will induce a voltage, per homopolar generator rules, and this voltage will thus polarize the coating. The question that then will arise is are you measuring, in the probe, the induced voltage applied by homopolar rules or the induced voltage due to electrostatic induction of the coating. However this can easily be resolved by using a plastic/rubber coated magnet.

A plastic/rubber coated magnet is an easy fix.  I was thinking the electret idea would allow for lower rotational speeds, higher humidity levels, weaker and smaller diameter magnets, etc.  However, cascading a few FET's to amplify the signal further is a much better setup and provides more flexibility during testing than the electret idea.  This makes things much more doable.

Edit: Added the last sentence.

[lumen]

Broli,

That looks like it might work for a test to see if the field cutting the probe would separate the charges as you show.
A FET probe is very sensitive and you would need to take care that other things were not inducing the charge.

My theory on rotating a magnet on it's axis is that the field always takes the position of less work, whether it rotates with the magnet or not depends on which one does the least work.

If an amount of work could be determined by how fast the charge would accumulate, then this might serve as a path to proving a rotating field!
It may be possible to add some accumulating plates on each end of the probe to improve the charge, or a super low voltage diode to prevent the charge from equalizing when the magnet stops rotating.