Win Hill: Inverse Marx Generator ??
in [Design]
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From: John Larkin on 12 Jul 2010 16:39 On Mon, 12 Jul 2010 12:32:54 +0200, o pere o <me(a)somewhere.net> wrote: >John Larkin wrote: >> On Sun, 11 Jul 2010 09:05:34 +0100, John Devereux >> <john(a)devereux.me.uk> wrote: >> >>> Jim Thompson <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> writes: >>> >>>> In the next few days, when I have time, I will issue a mathematical >>>> proof that Larkin is totally wrong. Watch for it ;-) >>>> >>>> Why haven't Win Hill and Phil Hobbs come to Larkin's defense? >>>> >>>> Bwahahahaha! >>> 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! >> >> Right. This being an electronics design group, and specifically a >> discussion about capacitors on schematics and not electrostatics, I >> assume that when we talk about the charge on a capacitor, it's zero if >> there's no voltage across its terminals, and any subsequent charge >> stored by the cap is equal to the integral of applied current. >> >> Q = CV = integral(I.dt) >> >> where V is the voltage across the cap >> C in farads, V volts, t seconds >> >> or in the rectangular case, >> >> Q = CV = IT >> >> starting from some initial point of Q=0, V=0. >> >> Q is measured in coulombs, which are dimensionally ampere-seconds. >> >> Given this definition of charge on/in a capacitor, one could further >> define the "total charge" in a circuit somehow. Carefully. >> >> Does anybody want to argue about that? >> >> John >> >> > >Hi John. > >Just trying to give some insight. q(t) is _defined_ (see my previous >post and the reference therein) as the integral of i(t) for _any_ >two-terminal element. For a capacitor it only equals C�v(t) if C is >time-invariant. > >If C is time-varying, i(t)=C(t)�dv(t)/dt+dC(t)/dt�v(t). In this case, >for instance, a discontinuity in C(t) causes an impulse in i(t) which >may be overlooked. > >Pere Time-variant caps are unusual in electronics. Varicaps, of course, but we don't often care about their energy considerations. Any voltage-variable capacitor, like a varicap or a high-K ceramic cap, can be used parametrically to get power gain. Both are also used to make shock lines, nonlinear transmission lines that have output risetimes faster than their inputs. Fun stuff. I guess the reason we don't have any true three-terminal variable capacitors (like, say, a gate that controls the capacitance between two other terminals) is that CV would be conserved so 0.5*C*V^2 would have to change, so where would the energy come from? John
From: Jim Thompson on 12 Jul 2010 17:24 On Mon, 12 Jul 2010 13:39:05 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Mon, 12 Jul 2010 12:32:54 +0200, o pere o <me(a)somewhere.net> wrote: > >>John Larkin wrote: >>> On Sun, 11 Jul 2010 09:05:34 +0100, John Devereux >>> <john(a)devereux.me.uk> wrote: >>> >>>> Jim Thompson <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> writes: >>>> >>>>> In the next few days, when I have time, I will issue a mathematical >>>>> proof that Larkin is totally wrong. Watch for it ;-) >>>>> >>>>> Why haven't Win Hill and Phil Hobbs come to Larkin's defense? >>>>> >>>>> Bwahahahaha! >>>> 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! >>> >>> Right. This being an electronics design group, and specifically a >>> discussion about capacitors on schematics and not electrostatics, I >>> assume that when we talk about the charge on a capacitor, it's zero if >>> there's no voltage across its terminals, and any subsequent charge >>> stored by the cap is equal to the integral of applied current. >>> >>> Q = CV = integral(I.dt) >>> >>> where V is the voltage across the cap >>> C in farads, V volts, t seconds >>> >>> or in the rectangular case, >>> >>> Q = CV = IT >>> >>> starting from some initial point of Q=0, V=0. >>> >>> Q is measured in coulombs, which are dimensionally ampere-seconds. >>> >>> Given this definition of charge on/in a capacitor, one could further >>> define the "total charge" in a circuit somehow. Carefully. >>> >>> Does anybody want to argue about that? >>> >>> John >>> >>> >> >>Hi John. >> >>Just trying to give some insight. q(t) is _defined_ (see my previous >>post and the reference therein) as the integral of i(t) for _any_ >>two-terminal element. For a capacitor it only equals C�v(t) if C is >>time-invariant. >> >>If C is time-varying, i(t)=C(t)�dv(t)/dt+dC(t)/dt�v(t). In this case, >>for instance, a discontinuity in C(t) causes an impulse in i(t) which >>may be overlooked. >> >>Pere > >Time-variant caps are unusual in electronics. Varicaps, of course, but >we don't often care about their energy considerations. > >Any voltage-variable capacitor, like a varicap or a high-K ceramic >cap, can be used parametrically to get power gain. Both are also used >to make shock lines, nonlinear transmission lines that have output >risetimes faster than their inputs. Fun stuff. > >I guess the reason we don't have any true three-terminal variable >capacitors (like, say, a gate that controls the capacitance between >two other terminals) is that CV would be conserved so 0.5*C*V^2 would >have to change, so where would the energy come from? > >John > From your drool ?:-) ...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 | Obama isn't going to raise your taxes...it's Bush' fault: Not re- newing the Bush tax cuts will increase the bottom tier rate by 50%
From: UltimatePatriot on 12 Jul 2010 17:30 On Mon, 12 Jul 2010 13:17:45 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > >I thought the "police special" rounds were about right. I guess the >police did too, since they were called "police specials." That term was coined by Colt long before cops decided on them. It is the original .38 Long Colt revolver round with a bit more juice and a few variations on the projectile as well. It is actually .357 caliber. It has been around since 1899 and economics had more to do with its ongoing selection than any other factor.
From: UltimatePatriot on 12 Jul 2010 17:33 On Mon, 12 Jul 2010 13:49:03 -0700, Fred Abse <excretatauris(a)invalid.invalid> wrote: >The link I quoted explains the difference. > Ding! Good way to get killed. Always count your shots and stop short of the last one, and reload *without* the telltale fling-and-ring.
From: krw on 12 Jul 2010 19:31
On Sun, 11 Jul 2010 20:12:07 -0700, UltimatePatriot <UltimatePatriot(a)thebestcountry.org> wrote: >On Sun, 11 Jul 2010 20:00:25 -0700, "JosephKK"<quiettechblue(a)yahoo.com> >wrote: > >>On Sat, 10 Jul 2010 14:40:56 -0500, Vladimir Vassilevsky >><nospam(a)nowhere.com> wrote: >> >>> >>> >>>John Larkin wrote: >>> >>>> On Sat, 10 Jul 2010 13:59:51 -0500, Vladimir Vassilevsky >>>> <nospam(a)nowhere.com> wrote: >>>> >>>> >>>>> >>>>>John Larkin wrote: >>>>> >>>>> >>>>> >>>>>>I'm an engineer. I design circuits. Philosophy is useless to me unless >>>>>>it allows me to quantify and measure things and predict what the >>>>>>numbers will mean. >>>>> >>>>>Yea, this is what good soldier Schweik used to say: >>>>> >>>>>"When a car runs out of gas, it stops. Even after been faced with this >>>>>obvious fact, they dare to talk about momentum". >>>>> >>>>> >>>> >>>> >>>> If Schweik has emptied the clip of his machine gun into you, you >>>> mostly likely would have died, and his philosophy would have worked >>>> better than yours. >>> >>>The philosophy can't stop a bullet, however it helps staying away from >>>the places where the bullets are whistling. >>> >>>> As an engineer, I use the theories that involve measurable phenomena >>>> and subsequently make electronics work, and avoid the ones that don't. >>> >>>As an engineer, you should know that machine guns don't use clips. >>> >>>VLV >> >>Which subset of machine guns are you talking about? Heard of AK47 or Uzi >>or M16? > > Those are "automatic rifles". > > They are what is a subset of 'machine gun'. If they are a subset of "machine gun", then he's right; (some) machine guns have clips/magazines. If you define a "machine gun" as one where an outside power source drives the mechanism, then I can't think of any that aren't belt-fed. OTOH, gas-driven automatics generally are magazine fed. |