Let's Take A Vote...
in [Design]
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From: John Fields on 24 Jul 2010 17:50 On Sat, 24 Jul 2010 13:48:57 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Sat, 24 Jul 2010 15:23:53 -0500, John Fields ><jfields(a)austininstruments.com> wrote: > >>On Sat, 24 Jul 2010 10:32:36 -0700, John Larkin >><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >> >>>On Sat, 24 Jul 2010 12:25:15 -0500, John Fields >>><jfields(a)austininstruments.com> wrote: >>> >>>>On Sat, 24 Jul 2010 10:13:48 -0700, John Larkin >>>><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>>> >>>>>On Sat, 24 Jul 2010 11:49:38 -0500, John Fields >>>>><jfields(a)austininstruments.com> wrote: >>>>> >>>>>>On Sat, 24 Jul 2010 08:30:43 -0700, John Larkin >>>>>><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>>>>> >>>>>>>On Sat, 24 Jul 2010 09:04:41 -0500, John Fields >>>>>>><jfields(a)austininstruments.com> wrote: >>>>>>> >>>>>>>>On Sat, 24 Jul 2010 08:15:03 -0500, John Fields >>>>>>>><jfields(a)austininstruments.com> wrote: >>>>>>>>On F>> >>>>>>>>>On Fri, 23 Jul 2010 17:38:45 -0700, John Larkin >>>>>>>>><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>>>>> >>>>>> >>>>>>>>>>Charge is measured in coulombs. Force is measured in newtons. So how >>>>>>>>>>is charge "a measure of force"? >>>>>>>>> >>>>>>>>>--- >>>>>>>>>news:2apl46hr8s01os8dv1aipdm19bcf64nec4(a)4ax.com >>>>>>>> >>>>>>>>--- >>>>>>>>Oh, and the first sentence of the cited Wikipedia article reads: >>>>>>>> >>>>>>>>"Electric charge is a physical property of matter which causes it >>>>>>>>to experience a force when near other electrically charged matter." >>>>>>>> >>>>>>>> >>>>>>>>JF >>>>>>> >>>>>>>If you experience a pig, does that make you a pig? >>>>>> >>>>>>--- >>>>>>That's just a silly diversionary tactic; measuring a force doesn't >>>>>>make you the force. >>>>>>--- >>>>>> >>>>>>>Look at the SI units if you want to determine if things are the same. >>>>>> >>>>>>--- >>>>>>That's just another silly diversionary tactic. >>>>> >>>>>Were you ever taught dimensional analysis? >>>>> >>>>>Obviously not. Give it a try: >>>>> >>>>>http://en.wikipedia.org/wiki/Dimensional_analysis >>>>> >>>>>The basic concept is that you can test all sorts of relationships for >>>>>plausibility by reducing their SI units. If the units don't agree, the >>>>>things can't be equal. Newtons aren't coulombs, so charge can't be >>>>>force. >>>> >>>>--- >>>>No one said it was. >>> >>> >>>You did: >>> >>>>>On the other hand, if Larkin's right and energy is conserved but >>>>>charge isn't, then since charge is a measure of force, unbalanced lost >>>>>charge might be able to be used for propulsion. >> >>--- >>Ah, now I see. >> >>You can't tell the difference between: "charge is force" and: "charge >>is a measure of force." >> >>JF > > >You might read this > >http://en.wikipedia.org/wiki/Dimensional_analysis#Commensurability > >since it's the easiest part of the article to understand. > >Engineers do sometimes break the rules and add non-commensurable >units, like designing a foldback power supply that limits the sum of a >voltage and a current. Addition is a poor substitute for >multiplication, but it's a lot easier to do with cheap parts. --- Yawnnnnnn... And, has nothing to with the _fact_ that charges attract or repel each other and that those attractions and repulsions are _mechanical_ in nature and can be measured using any convenient system and converted into any other convenient system as required. You do agree that one newton is equal to about 0.1020 kg wt or 0.2248 pounds avoirdupois, yes? For more fascinating reading, peruse: http://en.wikipedia.org/wiki/Avoirdupois
From: Grant on 24 Jul 2010 17:53 On Sat, 24 Jul 2010 13:38:23 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Sat, 24 Jul 2010 15:14:41 -0400, Phil Hobbs ><pcdhSpamMeSenseless(a)electrooptical.net> wrote: > >>Grant wrote: >>> On Sat, 24 Jul 2010 08:51:58 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>> >>>> On Sat, 24 Jul 2010 09:45:53 +0100, Martin Brown >>>> <|||newspam|||@nezumi.demon.co.uk> wrote: >>>> >>>>> On 23/07/2010 23:52, Jim Thompson wrote: >>>>>> Let's Take A Vote... >>>>>> >>>>>> While I write this up, hopefully sometime this weekend, let me ask for >>>>>> votes... >>>>>> >>>>>> How many think, as Larkin opines, "charge is not conserved" ?? >>>>> Hopefully not too many. But it is difficult to predict the behaviour of >>>>> electronics engineers - about half of them think Einstein was wrong :( >>>>>> How many think charge IS conserved ?? >>>>> Just about every physicist on the planet since Ben Franklin. >>>>> >>>>> It was the inconsistency of Ampere's Law with conservation of charge >>>>> that led Maxwell to formulate his famous equations and show that >>>>> oscillating fields of electromagnetic radiation travel at a constant >>>>> speed c in a vacuum. >>>>>> Just curious what I'm up against here. >>>>>> >>>>>> ...Jim Thompson >>>>> A idealised physics version of your original capacitor problem but >>>>> without the switch can be stated as the following problem: >>>>> >>>>> Two identical metal spheres with capacitance C are used. >>>>> Initially one is uncharged and the other with a charge Q >>>>> >>>>> They are brought together from infinity until they touch. >>>>> >>>>> Describe what happens and how the charge is distributed after they are >>>>> in electrical contact. You can add an infinite ground plane under the >>>>> experiment if it makes you feel better about the circuit analogue. >>>>> >>>> Where can I buy 0.33 uF surface-mount metal spheres? Are they >>>> expensive? I'd need ROHS, of course, on reels. [1] >>> >>> Second terminal optional?! >>> >>> But then, we sorta cater to 'monopole' charge when using human >>> body model's charge for anti-static measures. >>> >>> Grant. >>>> John >>>> >>>> [1] extra credit: how big would they be? >>>> >> >>Objects have both self-capacitance and mutual capacitance, so it's quite >>sensible to talk about a capacitor with only one lead. In Gaussian >>units, the self-capacitance of an isolated sphere of radius r >>centimetres is r. (The CGS unit of capacitance is the centimetre.) >> >>One cm ~= 1.12 pF, so 330,000 pF is about 30 km radius. That's quite a >>big reel! >> >>Cheers >> >>Phil Hobbs > >The entire planet is only about a 700 uF cap, but the voltage rating >is pretty good. Bob Pease presided over a debate a few years ago about >the capacitance between the earth and the moon; there were two >distinct values cited, and he came down on the side of the smaller one >and ridiculed the other. I think it depends on whether you do a >2-terminal or a 3-terminal measurement. One equation approaches zero C >with distance, the other levels off. > >I wonder what the net voltage of "ground" is. Since we keep getting >whacked with solar wind (net protons?) we might actually be heavily >charged. There's a considerable gradient at the surface. Net voltage with respect to what? Solar wind goes a long way. We get those huge CMEs that wipeout power lines over large areas very rarely. And, sun is building up to next cycle, I've read they're not sure how bad it could be this time around because so much been put up in orbit since the last cycle. Grant. > >John >
From: Jim Thompson on 24 Jul 2010 18:22 On Sun, 25 Jul 2010 07:44:25 +1000, Grant <omg(a)grrr.id.au> wrote: >On Sat, 24 Jul 2010 10:57:27 -0700, Jim Thompson <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote: > >>On Sun, 25 Jul 2010 03:52:05 +1000, Grant <omg(a)grrr.id.au> wrote: >> >>>On Sat, 24 Jul 2010 08:51:58 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>> >>>>On Sat, 24 Jul 2010 09:45:53 +0100, Martin Brown >>>><|||newspam|||@nezumi.demon.co.uk> wrote: >>>> >>>>>On 23/07/2010 23:52, Jim Thompson wrote: >>>>>> Let's Take A Vote... >>>>>> >>>>>> While I write this up, hopefully sometime this weekend, let me ask for >>>>>> votes... >>>>>> >>>>>> How many think, as Larkin opines, "charge is not conserved" ?? >>>>> >>>>>Hopefully not too many. But it is difficult to predict the behaviour of >>>>>electronics engineers - about half of them think Einstein was wrong :( >>>>>> >>>>>> How many think charge IS conserved ?? >>>>> >>>>>Just about every physicist on the planet since Ben Franklin. >>>>> >>>>>It was the inconsistency of Ampere's Law with conservation of charge >>>>>that led Maxwell to formulate his famous equations and show that >>>>>oscillating fields of electromagnetic radiation travel at a constant >>>>>speed c in a vacuum. >>>>>> >>>>>> Just curious what I'm up against here. >>>>>> >>>>>> ...Jim Thompson >>>>> >>>>>A idealised physics version of your original capacitor problem but >>>>>without the switch can be stated as the following problem: >>>>> >>>>>Two identical metal spheres with capacitance C are used. >>>>>Initially one is uncharged and the other with a charge Q >>>>> >>>>>They are brought together from infinity until they touch. >>>>> >>>>>Describe what happens and how the charge is distributed after they are >>>>>in electrical contact. You can add an infinite ground plane under the >>>>>experiment if it makes you feel better about the circuit analogue. >>>>> >>>> >>>>Where can I buy 0.33 uF surface-mount metal spheres? Are they >>>>expensive? I'd need ROHS, of course, on reels. [1] >>> >>>Second terminal optional?! >>> >>>But then, we sorta cater to 'monopole' charge when using human >>>body model's charge for anti-static measures. >>> >>>Grant. >>>> >>>>John >>>> >>>>[1] extra credit: how big would they be? >>>> >> >>The human body model tester has a ground terminal. >> >> ...Jim Thompson > >Yes, I know the body model has a ground. But my point was that >the human can deliver a static shock without being grounded. >Carrying a static charge above (below?) ground. > >Grant. A human being is a capacitor when wearing Ecco shoes ;-) ...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 | Spice is like a sports car... Only as good as the person behind the wheel.
From: Phil Hobbs on 24 Jul 2010 18:37 John Larkin wrote: > On Sat, 24 Jul 2010 15:14:41 -0400, Phil Hobbs > <pcdhSpamMeSenseless(a)electrooptical.net> wrote: > >> Grant wrote: >>> On Sat, 24 Jul 2010 08:51:58 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>> >>>> On Sat, 24 Jul 2010 09:45:53 +0100, Martin Brown >>>> <|||newspam|||@nezumi.demon.co.uk> wrote: >>>> >>>>> On 23/07/2010 23:52, Jim Thompson wrote: >>>>>> Let's Take A Vote... >>>>>> >>>>>> While I write this up, hopefully sometime this weekend, let me ask for >>>>>> votes... >>>>>> >>>>>> How many think, as Larkin opines, "charge is not conserved" ?? >>>>> Hopefully not too many. But it is difficult to predict the behaviour of >>>>> electronics engineers - about half of them think Einstein was wrong :( >>>>>> How many think charge IS conserved ?? >>>>> Just about every physicist on the planet since Ben Franklin. >>>>> >>>>> It was the inconsistency of Ampere's Law with conservation of charge >>>>> that led Maxwell to formulate his famous equations and show that >>>>> oscillating fields of electromagnetic radiation travel at a constant >>>>> speed c in a vacuum. >>>>>> Just curious what I'm up against here. >>>>>> >>>>>> ...Jim Thompson >>>>> A idealised physics version of your original capacitor problem but >>>>> without the switch can be stated as the following problem: >>>>> >>>>> Two identical metal spheres with capacitance C are used. >>>>> Initially one is uncharged and the other with a charge Q >>>>> >>>>> They are brought together from infinity until they touch. >>>>> >>>>> Describe what happens and how the charge is distributed after they are >>>>> in electrical contact. You can add an infinite ground plane under the >>>>> experiment if it makes you feel better about the circuit analogue. >>>>> >>>> Where can I buy 0.33 uF surface-mount metal spheres? Are they >>>> expensive? I'd need ROHS, of course, on reels. [1] >>> Second terminal optional?! >>> >>> But then, we sorta cater to 'monopole' charge when using human >>> body model's charge for anti-static measures. >>> >>> Grant. >>>> John >>>> >>>> [1] extra credit: how big would they be? >>>> >> Objects have both self-capacitance and mutual capacitance, so it's quite >> sensible to talk about a capacitor with only one lead. In Gaussian >> units, the self-capacitance of an isolated sphere of radius r >> centimetres is r. (The CGS unit of capacitance is the centimetre.) >> >> One cm ~= 1.12 pF, so 330,000 pF is about 30 km radius. That's quite a >> big reel! >> >> Cheers >> >> Phil Hobbs > > The entire planet is only about a 700 uF cap, but the voltage rating > is pretty good. Bob Pease presided over a debate a few years ago about > the capacitance between the earth and the moon; there were two > distinct values cited, and he came down on the side of the smaller one > and ridiculed the other. I think it depends on whether you do a > 2-terminal or a 3-terminal measurement. One equation approaches zero C > with distance, the other levels off. > > I wonder what the net voltage of "ground" is. Since we keep getting > whacked with solar wind (net protons?) we might actually be heavily > charged. There's a considerable gradient at the surface. > > John > > <dim-memory-on> The Sun is nearly electrically neutral, because it continuously streams plasma, which is electrically conductive. If there were any really big excess charge, there would be an excess of one polarity in the solar wind until it was dissipated. (There may be some solar processes that act to maintain a smallish charge on the Sun, but it won't be much.) The whole Earth (solid plus atmosphere) is also nearly electrically neutral, due to being immersed in a conducting medium (the solar wind). The solid Earth has a net negative charge of something like 1E10 coulombs, iirc, and the atmosphere a nearly equal positive charge, maintained by thunderstorms. (Google will have a better handle on it, I expect.) <dim-memory-off> Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net
From: John Larkin on 24 Jul 2010 18:46
On Sat, 24 Jul 2010 16:50:09 -0500, John Fields <jfields(a)austininstruments.com> wrote: >On Sat, 24 Jul 2010 13:48:57 -0700, John Larkin ><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > >>On Sat, 24 Jul 2010 15:23:53 -0500, John Fields >><jfields(a)austininstruments.com> wrote: >> >>>On Sat, 24 Jul 2010 10:32:36 -0700, John Larkin >>><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>> >>>>On Sat, 24 Jul 2010 12:25:15 -0500, John Fields >>>><jfields(a)austininstruments.com> wrote: >>>> >>>>>On Sat, 24 Jul 2010 10:13:48 -0700, John Larkin >>>>><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>>>> >>>>>>On Sat, 24 Jul 2010 11:49:38 -0500, John Fields >>>>>><jfields(a)austininstruments.com> wrote: >>>>>> >>>>>>>On Sat, 24 Jul 2010 08:30:43 -0700, John Larkin >>>>>>><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>>>>>> >>>>>>>>On Sat, 24 Jul 2010 09:04:41 -0500, John Fields >>>>>>>><jfields(a)austininstruments.com> wrote: >>>>>>>> >>>>>>>>>On Sat, 24 Jul 2010 08:15:03 -0500, John Fields >>>>>>>>><jfields(a)austininstruments.com> wrote: >>>>>>>>>On F>> >>>>>>>>>>On Fri, 23 Jul 2010 17:38:45 -0700, John Larkin >>>>>>>>>><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>>>>>> >>>>>>> >>>>>>>>>>>Charge is measured in coulombs. Force is measured in newtons. So how >>>>>>>>>>>is charge "a measure of force"? >>>>>>>>>> >>>>>>>>>>--- >>>>>>>>>>news:2apl46hr8s01os8dv1aipdm19bcf64nec4(a)4ax.com >>>>>>>>> >>>>>>>>>--- >>>>>>>>>Oh, and the first sentence of the cited Wikipedia article reads: >>>>>>>>> >>>>>>>>>"Electric charge is a physical property of matter which causes it >>>>>>>>>to experience a force when near other electrically charged matter." >>>>>>>>> >>>>>>>>> >>>>>>>>>JF >>>>>>>> >>>>>>>>If you experience a pig, does that make you a pig? >>>>>>> >>>>>>>--- >>>>>>>That's just a silly diversionary tactic; measuring a force doesn't >>>>>>>make you the force. >>>>>>>--- >>>>>>> >>>>>>>>Look at the SI units if you want to determine if things are the same. >>>>>>> >>>>>>>--- >>>>>>>That's just another silly diversionary tactic. >>>>>> >>>>>>Were you ever taught dimensional analysis? >>>>>> >>>>>>Obviously not. Give it a try: >>>>>> >>>>>>http://en.wikipedia.org/wiki/Dimensional_analysis >>>>>> >>>>>>The basic concept is that you can test all sorts of relationships for >>>>>>plausibility by reducing their SI units. If the units don't agree, the >>>>>>things can't be equal. Newtons aren't coulombs, so charge can't be >>>>>>force. >>>>> >>>>>--- >>>>>No one said it was. >>>> >>>> >>>>You did: >>>> >>>>>>On the other hand, if Larkin's right and energy is conserved but >>>>>>charge isn't, then since charge is a measure of force, unbalanced lost >>>>>>charge might be able to be used for propulsion. >>> >>>--- >>>Ah, now I see. >>> >>>You can't tell the difference between: "charge is force" and: "charge >>>is a measure of force." >>> >>>JF >> >> >>You might read this >> >>http://en.wikipedia.org/wiki/Dimensional_analysis#Commensurability >> >>since it's the easiest part of the article to understand. >> >>Engineers do sometimes break the rules and add non-commensurable >>units, like designing a foldback power supply that limits the sum of a >>voltage and a current. Addition is a poor substitute for >>multiplication, but it's a lot easier to do with cheap parts. > >--- >Yawnnnnnn... > >And, has nothing to with the _fact_ that charges attract or repel each >other and that those attractions and repulsions are _mechanical_ in >nature and can be measured using any convenient system and converted >into any other convenient system as required. > >You do agree that one newton is equal to about 0.1020 kg wt or 0.2248 >pounds avoirdupois, yes? > "kg wt" is not an SI unit, so no. The units don't conform, so the quantities can't be equal. SI units were inventented to clarify things like this. If by "pounds avoirdupois" you mean lbf, pounds force, yes. The relation there is a dimensionless scaler, so is OK. John |