Win Hill: Inverse Marx Generator ??
in [Design]
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From: Michael A. Terrell on 18 Jul 2010 15:41 Jim Thompson wrote: > > On Thu, 15 Jul 2010 18:34:23 -0700, "Artemus" <bogus(a)invalid.org> > wrote: > > >"Jim Thompson" <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote in message > >news:1ibv36d2lmvvptmtq7e58cjvb8qqhq90ci(a)4ax.com... > >> > >> It's _really_ easy once you stare at the waveforms for awhile... I > >> _knew_ charge has to be conserved, but I finally saw the answer while > >> half dozing at a granddaughter's swim party :-) > > > >A capacitor in an electronic circuit doesn't store charge, it stores energy. > >The circuit passes a charge thru a capacitor. For every electron that enters > >the + end another electron leaves the - end. So the capacitor doesn't store > >charge with respect to the external circuit any more than a resistor does. > >Art > > Huh? All his capacitors are shorted! What do you expect from an invalid, anyway? -- Anyone wanting to run for any political office in the US should have to have a DD214, and a honorable discharge.
From: Michael A. Terrell on 18 Jul 2010 15:42 Tim Williams wrote: > > "Artemus" <bogus(a)invalid.org> wrote in message news:i1of1p$g66$1(a)news.eternal-september.org... > > Said another way - the external circuit uses energy to move charge > > (electrons) from one plate of the capacitor to the other. No net electrons > > are added to the capacitor, ergo it has no charge with respect to the rest > > of the circuit. > > To be specific, that current is the displacement current. > > Curiously, that current even appears to flow in free space, in the absence of matter. I don't know if the quantum vacuum has anything to say about that. > > Maxwell's original derivation of displacement current assumed polarization charge seperation occured in a polarizable medium. That works for plastic, and it could even work for air, but it's a lot harder to explain for a vacuum. That's why no one can explain dimbulb... -- Anyone wanting to run for any political office in the US should have to have a DD214, and a honorable discharge.
From: Jim Thompson on 20 Jul 2010 19:21
On Wed, 14 Jul 2010 17:52:32 -0700, Jim Thompson <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote: >On Wed, 14 Jul 2010 18:52:48 +0100, John Devereux ><john(a)devereux.me.uk> wrote: > >>Jim Thompson <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> writes: >> >>> On Wed, 14 Jul 2010 08:25:33 -0700, John Larkin >>> <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>> >>>>On Tue, 13 Jul 2010 08:07:40 +0100, John Devereux >>>><john(a)devereux.me.uk> wrote: >>>> >>>>>"JosephKK"<quiettechblue(a)yahoo.com> writes: >>>>> >>>>>> On Sun, 11 Jul 2010 09:05:34 +0100, John Devereux <john(a)devereux.me.uk> >>>>>> wrote: >> >>[...] >> >>>>>>>I'm no Phil Hobbs, but isn't all this argument because we are conflating >>>>>>>two different usages of "charge"? >>>>>>> >>>>>>>The "charge" on a capacitor, as somone pointed out already, is really >>>>>>>charge *separation* (dilectric polarization). The Q=CV refers to a >>>>>>>*separation* of charge, not an absolute quantity. The "absolute" charge >>>>>>>- the total number of electrons minus the number of protons - is >>>>>>>normally low or zero. Unless your whole circuit picks up an >>>>>>>electrostatic charge from somewhere else. It is this "absolute" charge >>>>>>>which is conserved, the "Q=CV" "charge" of normal electronics is >>>>>>>not. Take a solar cell charging a battery for one obvious example. As >>>>>>>Larkin would say, where did the charge come from? Photons don't carry >>>>>>>charge! >>>>>> >>>>>> Gosh, in all the semiconductor physics i have seen it is "pair >>>>>> generation". No net charge change involved. >>>>> >>>>>But in normal electronics usage, we would say that the battery or >>>>>capacitor was charged by the solar cell! "Charge separation" or "pair >>>>>generation" - there *is no* physical net charge in reality. Yet we >>>>>always talk of the "charge of a capacitor" or "charging a battery". It >>>>>is what this whole thread has been about (and I believe it is this usage >>>>>that Larkin had in mind). >>>> >>>>Of course. This is an electronics design group, not a >>>>retired-physics-teacher debating society. We can measure the charge >>>>that we pump into a capacitor and measure what we get out. We can >>>>watch a resistor charge a capacitor at a mathematically predictable >>>>rate. Statements like "there is no net charge on the capacitor" that's >>>>got 100 volts across it don't help a lot in real life. >>>> >>>>John >>> >>> John Larkin _still_ can't answer where the charge came from... must >>> have been immaculate conception :-) >> >>Of course he can. It depends on how you want to use the word. It is >>either >> >>1) zero >> >>Technically accurate but useless. >> >>or >> >>2) The current through the capacitor produces a charge >>separation. Electrons pile up on one plate and are depleted on the >>other, producing a potential difference. >> >>*Normally* referred to as "charging the capacitor". We *normally* say >>the "charge" in the capacitor is Q = CV = integral of the current. >> >>Or do we have to stop saying that here now? >> >>"C1 experiences a charge separation due to the current through R3. This >>charge separation / electron-hole pair production process produces a >>potential difference equal to that between the non-inverting input and >>the zero reference. The comparator switches. The current through R3 then >>acts to reverse the charge separation process until..." > >Neither is correct! Wheee! I'm finding out who can and who can't >analyze this :-( > I should have issued "partial credit". My apologies! ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | |