Ultracaps tested for excess energy

[MileHigh]

Vortex1:

You are the man!  lol   Instead of a scope, I was thinking of using a digital multimeter.  Perhaps more like two minutes to reach the 63% level so that the DMM display update rate issue is minimized.

Also a few questions about the dielectric absorption.  Does charge get "pressed" into the dielectric such that it looks like a parallel "phantom" capacitor with a quasi-exponential decay?  What is the quasi time constant?  A few minutes?

MileHigh

[innovation_station]

beleave me i understand how many things run and i have met  some people one could say ....


if ya know what i mean

peace !

ist

[MileHigh]

Ist:

A little song dedicated to you....  May it play in your head for days and days!  lol

Well there's gonna be a freakers ball
Tonight at the freakers hall
And you know, you're invited one and all

Come on babies grease your lips
Grab your hats and swing your hips
Don't forget to bring your whips
We're going to the freakers ball

Blow your whistle and bang your gong
Roll up something to take along
It feels so good it must be wrong
We're freakin at the freakers ball

Party on Ist!!!

MileHigh

[Vortex1]

MileHigh, you are correct

From wiki

Dielectric absorption (soakage)

Some types of dielectrics, when they have been holding a high voltage for a long time, maintain a "memory" of that voltage. After they have been quickly discharged to zero volts, if they are then left disconnected, the voltage across the capacitor will slowly recover some fixed percentage -- up to 10% -- of the "remembered" voltage. This percentage is a measure of the dielectric absorption, and depends on the type of dielectric.

In the construction of long-time-constant integrators, it is important that the capacitor will not retain a residual charge when shorted. This phenomenon of unwanted charge storage is called dielectric absorption or soakage, and it effectively creates a memory effect in the capacitor. This is a non-linear phenomenon, and is also important when building very low distortion filters. This is also why, for safety, high voltage capacitors are stored with their terminals short circuited.

For long-time-constant integrators and sample-and-hold systems, good designers pick capacitors that have almost no dielectric absorption hysteresis -- capacitors such as those employing polystyrene, polypropylene, NPO ceramic, and Teflon dielectrics.

For more info on modeling, download da.pdf from the wiki site

MileHigh I agree with your earlier comments on cores, wire size etc.

It is useful to note that "copper and iron" are designed out of power supplies for size and cost of materials reasons in favor of "copper and exotic ferrites" and semiconductors as the switching frequencies go higher and higher.

If cost and size are not important, one could minimize switching losses by simply operating at low frequencies and use oversize magnetic cores and a minimum of heavy guage wire (fewer turns).

Of course the switcher would be much bulkier.

I don't know if anyone has ever taken engineering of switchers in the direction opposite the cost/size trends, but it would be interesting to see how far one could go in that direction.

[MileHigh]

Vortex1:

Thank you for all of that great information, it was the icing on the cake.  I realize that what I posted tonight with a "top level" engineering-style description of the issues involved in designing the most efficient Joule Thief possible.  For a lot of people around here the devil is in the details and they won't know to get from top-level point A to how to build it point Z.  However, there is some good stuff on the table for discussion and if there are any keeners out there they can find friends around here that can flesh out the details and hopefully have a lot of fun doing it.

MileHigh