Spontaneous charging radiantly charged capacitor research group

[rave154]

INQ, my mind is Full! right now, ( soo many thoughtssssssssssss )

but, just wanted to give you this,

being australian youre probbaly already aware of this guy and maybe this song.....if youre not.......brace yourself cos youre ( and your missus ) are in for a treat ( song that im learning btw )...

YouTube - John Butler Trio - Ocean (Live at Federation Square)

[Inquorate]

John Butler trio

Yep seen him live a couple of times. Best guitarist I've ever seen.

Love and light

[lamare]

Hi all,

This sure is an interesting phenomenon. It may be that it is possible to form a (non-permanent?) electret inside (certain types?) of capacitors.

The dielectric material inside a capacitor can be polarized using an electric field. When the capacitor discharges, this polarization normally gets lost pretty fast. However, there is a "memory" effect in that the polarization is not immediately gone when a cap is short circuited:

Understand Capacitor Soakage to Optimize Analog Systems

This effect is also known as "dielectric relaxation":

Journeys End: Self charging behaviour of electrolyte capacitors

"During my physics lab this afternoon, I found that discharged electrolyte capacitors re-charges to a percentage of its original voltage when left alone as open circuit. I was informed this effect is called dielectric relaxation by one of the tutors."


Now, it appears logical that when the capacitor is charged with high voltage pulses, you perhaps somehow "super polarize" the dielectric. That would mean you can enhance this "dielectric relaxation" effect to such an extent that you practically create a non-permanent electret, that keeps alive much longer then a few microseconds, perhaps up to minutes or even hours.

If that is the case, you could come up with a system that feeds "spikes" to the cap in order to maintain that non-permanent electret effect for a prolonged period of time, while only taking a minimal amount of energy to maintain the electret.


Also see:

TopTinkers.com :: The Self-charging Capacitor

"The Self-charging Capacitor

I have observed several situations where this phenomenon arises - a capacitor which spontaneously builds up a charge after being short circuited. Some of the experiments to observe this effect are remarkably simple, and can be done with little more than kitchen utensils. "

[lamare]

Some more info on electrets..

Electret - Wikipedia, the free encyclopedia

"Electrets can also be manufactured by embedding excess negative charge within a dielectric using a particle accelerator, or by stranding charges on, or near, the surface using high voltage corona discharges, a process called corona charging. Excess charge within an electret decays exponentially. The decay constant is a function of the material's relative dielectric constant and its bulk resistivity. Materials with extremely high resistivity, such as Teflon, may retain excess charge for many hundreds of years. Most commercially produced electrets are based on fluoropolymers (eg. amorphous Teflon) machined to thin films."


Electrets

"A dielectric is a non-conducting material which has the unique ability of preventing electrical conduction but is at the same time capable of absorbing electric charge. Indeed, it will carry on absorbing charge until its saturation capacity is reached, whereupon, if its power source is still connected and still trying to pour more electricity into it it will rupture and a path will be created through it for current to discharge. This phenomenon, called dielectric breakdown is most certainly to be avoided for it renders the solid material useless thereafter. If, however, before it ruptures the charge accumulated within the dielectric rises toward its saturation point and reaches a level of voltage higher than the voltage of the charging circuit, then the dielectric’s voltage will discharge itself (just like a short circuit - very violently) back through the power source.

From the very earliest days of electronics discoverers such as Faraday, Maxwell, and Lord Kelvin found that dielectrics didn’t merely insulate; and that even the humble Leyden jar condenser was found to hold significantly more electricity, surface area for surface area, than a flat-sheet condenser with air between it’s sheets – because it had a dielectric of glass sandwiched between its electrodes. Dielectrics were found to exhibit what was then termed ‘elastic stress’ which enabled its structure to absorb unusually large quantities of charge. "

"Since 1919 until 1970's thermal method was used (DC voltage applied by electrodes to heated samples).

The original method, using dipolar polarisation with space charge is linked to the "two-charge theory", applicable to waxes and to polymers like Mylar.

Electron beam method (low-energy beams of about 20KeV in vacuum) was used for controlled charging and for research application from the 1960's to today.

Nowadays (since 1970's), the usual method is to use polymer materials. Many modern electrets have only space or surface charge (like Teflon or Polypropylene electrets), but no dipole polarisation. The modern electrets need few kV (3 to 10) to be made. The voltage is applied through external electrodes to a piece of Teflon foil, 25 to 100 microns thick (preferably metalized on one side). Or, better a corona discharge operates with a needle voltage of 5 to 10kV. Then the non metalized side of the Teflon is charged. Polypropylene as well as Mylar can be used.

Corona method is preferred nowadays for industrial production, often applied at elevated temperatures.

The current required is usually less than 1 mA, since the materials are highly insulated and the current is therefore very small.

Concerning the ratio of applied voltage and output voltage :

It depends on the charging process and on many other parameters. In corona charging, surface potential of 2kV can be easily obtained with a needle voltage of 5 to 10kV. With contact charging electrodes, one could expect the resulting voltage to be about 50 percent of the applied voltage, up to about 1 to 2kV. No general rule can be given, since many parameters enter."


http://www.zju.edu.cn/jzus/2004/0408/040806.pdf

"When electrets are formed by corona charging, various kinds of ions derived from the corona discharge in the air are injected from electrode to materials. Some of the ions recombine on the surface of the materials, giving rise to chemical changes in it, while the remaining ions penetrate into the bulk of the materials, where their charge becomes trapped, first by deep traps, then by shallow traps, following which may be released by corona-generated excited molecules and transferred into the bulk of the material in the internal electric field related to the injected charge (Hilczer and Malecki, 1986)."


It doesn't seem too far-fetched to assume that high-voltage spikes can produce similar results in a dielectricum...

Also see:
http://ether.sciences.free.fr/acroba...anelectret.pdf

The similarity between that recipe and pulse-charging a capacitor is striking....

[rave154]

Cap swapping circuits

INQ, im going to post these circuits here, its not strictly on topic, but may play a part, so at least its here for reference....

[Inquorate]

Series parallel

INQ, im going to post these circuits here, its not strictly on topic, but may play a part, so at least its here for reference....

Sweet dude, Thankyou for posting these schematics!

Love and light

[Inquorate]

The first day of christmas

When I finally get back into the lab I'm going to have a crack at something like this;

05/12/2009 schematic - Vox

Just thought I'd share

[Inquorate]

re the above; some of the transistors are the wrong way around etc. But you get the idea

Love and light

[Inquorate]

A question

A fully charged capacitor or a battery sitting on a bench will in a short or long period of time, lose it's charge.

Why?

Consider the capacitor; do the electrons disappear on one plate of the capacitor?

Or do they appear on the other plate?

Or does the electrostatic tension of the dielectric relax, causing the electrons on the plate to decrease the amount and polarity of energy they had been forced to hold?

The third option sounds more reasonable to me on account of the MIT experiment but I'm interested in other's opinions.

[Matthew Jones]

Well there could be others.
The environment is adding oppositely charged energies to the capacitor plate, neutralizing the charge.
The energy on the plate is in a more rapid state of entropy and is degraded to a smaller particle reducing the charge.


Just a thought.

Matt

[sucahyo]

A fully charged capacitor or a battery sitting on a bench will in a short or long period of time, lose it's charge.

Why?

Another option:
- internal discharge, the electrical isolation between pole is not infinite. Isolation will act as load. low isolation resistance value allow faster self discharge.

- chemical reaction, ion between pole may pass through the isolation and reduce the potential overtime. kind of reverted electrolysis.

[Inquorate]

Next question

Thanks Sucahyo and mathew jones.

Now, which answer fits the situation where a conditioned (Electret effect in the dielectric) capacitor charges quicker, discharges longer, and holds it's charge better?

Ps I'm not 'testing', I don't have the 'right' answer. I just really want to know.

[CosmicFarmer]

Charging observed

@ rave Thanks for the cap swap circuits!


I was testing my 2.7v 650F caps if they could maintain a charge because I doubted them. Gave them all a zap from 2 "dead" batteries from a microsoft Xbox controller which was at 2.4 volts. Gave them all 75mv or higher initial holding charge. 3 out of 4 dropped 10mv overnight. one gained 5mv.

I dont know. I read voltages 3 times, each time 5 hours apart and about 5 mv drop on all of them. the third reading, 10 hours later on capacitor "triangle" I named it, it held at 91.3 from a charge of 85. These all were shorted previously.

I dont know what I did but I do know 1 of those 4 I experimented with my sec and ever since then I couldn't short it past 100mv so I think that was the one. I short them all and eventually one gets a charge back. Hmm.

[Inquorate]

That's the one

@ rave Thanks for the cap swap circuits!


I was testing my 2.7v 650F caps if they could maintain a charge because I doubted them. Gave them all a zap from 2 "dead" batteries from a microsoft Xbox controller which was at 2.4 volts. Gave them all 75mv or higher initial holding charge. 3 out of 4 dropped 10mv overnight. one gained 5mv.

I dont know. I read voltages 3 times, each time 5 hours apart and about 5 mv drop on all of them. the third reading, 10 hours later on capacitor "triangle" I named it, it held at 91.3 from a charge of 85. These all were shorted previously.

I dont know what I did but I do know 1 of those 4 I experimented with my sec and ever since then I couldn't short it past 100mv so I think that was the one. I short them all and eventually one gets a charge back. Hmm.

Sounds like one of your supercaps is slightly conditioned. Might have to try condition my own supercaps..

Love and light

[Inquorate]

Youtube comments

@ cosmic - in reply to your youtube video comment (youtube disabled 'normal desktop page' for mobile phones so I can't reply to comments and messages)

The effect does seem to wear off, but then again, I have one 100v 10000 uF cap that builds up 18v after a day or two. It's done this repeatedly.