Let's Take A Vote...
in [Design]
|
From: Phil Hobbs on 29 Jul 2010 23:59 George Herold wrote: > On Jul 29, 11:46 am, Phil Hobbs > <pcdhSpamMeSensel...(a)electrooptical.net> wrote: >> John Larkin wrote: >>> On Thu, 29 Jul 2010 15:10:41 +0100, John Devereux >>> <j...(a)devereux.me.uk> wrote: >>>> John Larkin <jjlar...(a)highNOTlandTHIStechnologyPART.com> writes: >>>>> On Thu, 29 Jul 2010 13:38:51 +0300 (EEST), Okkim Atnarivik >>>>> <Okkim.Atnari...(a)twentyfout.fi.invalid> wrote: >>>>>> John Larkin <jjlar...(a)highnotlandthistechnologypart.com> wrote: >>>>>> : Do thermals matter to you? Latching relays are fabulous. As analog >>>>>> : switches, no semiconductor comes close. We recently measured the wiper >>>>>> Interestingly, in the LHe temperature OptoMOS switches can be closed >>>>>> but not opened. Switch-off relies on the charge leaking away from the >>>>>> MOSFET gate, and this leak obviously freezes. >>>>> Maybe you're just not waiting long enough. A 2N7002 will keep itself >>>>> on or off, gate floating, for days. A cryo temps, that might extend to >>>>> a few million years. I'm impressed that they work at all. >>>>> Possibly they use a silicon resisor for the pulldown, and the >>>>> resistance goes way, way up when it's cold. So it might turn off in a >>>>> few weeks. >>>>> Optomos SSRs are great signal switches too. I recently blew up a bunch >>>>> of Clare parts, to find their voltage:current destruct limits. The >>>>> datasheets are horrible about that. >>>> Yes, pathetic for something clearly intended as an I/O component. I got >>>> no answer from them either about it. >>>> [...] >>> I have some crude point-of-destruction SOAR graphs if you're >>> interested, on their CPC1008N part. After blowing a bunch up, I >>> learned that you can look at waveforms and pretty accurately >>> anticipate second breakdown (or whatever makes them fail) just before >>> it happens. Plotting graphs is much faster when you don't have to >>> replace the part every data point, like the civil engineering students >>> breaking concrete beams. >>> John >> It's amazing that they remain civil--I mean, War between the States, sorry. >> >> Cheers >> >> Phil Hobbs >> >> (Recently saw the Confederate Correct-orrr episode of Rocky & Bullwinkle >> again. Brilliant.) > > What? Phil I thought your nose was always in a book, not pointed at > the TV? > > George H. > I don't watch TV or movies normally, but I'm not ideological about it. (Of course the last movie I watched was in 1987, but that's because there haven't been any good ones lately.) My winsome #1 daughter (who grew up with no TV in the house, courtesy of her cruel and inhuman father) bought the Nth season of Rocky & Bullwinkle on DVD, and I happened to pass by the room she was watching it in. I always did like the Confederate Corrector episode. (And #2 daughter is winsome too, in case she's reading this.) My kids also keep me in good reading material--on Sunday, when I was getting ready to go on my monthly trip to NM, the same daughter gave me a book on the Trojan War to read on the airplane, and my son gave me his favourite Hemingway. So yeah, I read a lot, and I've been doing more normal circuit design in the past year than I have in a looong time. Fun. :) 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: Richard Henry on 30 Jul 2010 00:29 On Jul 29, 8:59 pm, Phil Hobbs <pcdhSpamMeSensel...(a)electrooptical.net> wrote: > George Herold wrote: > > On Jul 29, 11:46 am, Phil Hobbs > > <pcdhSpamMeSensel...(a)electrooptical.net> wrote: > >> John Larkin wrote: > >>> On Thu, 29 Jul 2010 15:10:41 +0100, John Devereux > >>> <j...(a)devereux.me.uk> wrote: > >>>> John Larkin <jjlar...(a)highNOTlandTHIStechnologyPART.com> writes: > >>>>> On Thu, 29 Jul 2010 13:38:51 +0300 (EEST), Okkim Atnarivik > >>>>> <Okkim.Atnari...(a)twentyfout.fi.invalid> wrote: > >>>>>> John Larkin <jjlar...(a)highnotlandthistechnologypart.com> wrote: > >>>>>> : Do thermals matter to you? Latching relays are fabulous. As analog > >>>>>> : switches, no semiconductor comes close. We recently measured the wiper > >>>>>> Interestingly, in the LHe temperature OptoMOS switches can be closed > >>>>>> but not opened. Switch-off relies on the charge leaking away from the > >>>>>> MOSFET gate, and this leak obviously freezes. > >>>>> Maybe you're just not waiting long enough. A 2N7002 will keep itself > >>>>> on or off, gate floating, for days. A cryo temps, that might extend to > >>>>> a few million years. I'm impressed that they work at all. > >>>>> Possibly they use a silicon resisor for the pulldown, and the > >>>>> resistance goes way, way up when it's cold. So it might turn off in a > >>>>> few weeks. > >>>>> Optomos SSRs are great signal switches too. I recently blew up a bunch > >>>>> of Clare parts, to find their voltage:current destruct limits. The > >>>>> datasheets are horrible about that. > >>>> Yes, pathetic for something clearly intended as an I/O component. I got > >>>> no answer from them either about it. > >>>> [...] > >>> I have some crude point-of-destruction SOAR graphs if you're > >>> interested, on their CPC1008N part. After blowing a bunch up, I > >>> learned that you can look at waveforms and pretty accurately > >>> anticipate second breakdown (or whatever makes them fail) just before > >>> it happens. Plotting graphs is much faster when you don't have to > >>> replace the part every data point, like the civil engineering students > >>> breaking concrete beams. > >>> John > >> It's amazing that they remain civil--I mean, War between the States, sorry. > > >> Cheers > > >> Phil Hobbs > > >> (Recently saw the Confederate Correct-orrr episode of Rocky & Bullwinkle > >> again. Brilliant.) > > > What? Phil I thought your nose was always in a book, not pointed at > > the TV? > > > George H. > > I don't watch TV or movies normally, but I'm not ideological about it. > (Of course the last movie I watched was in 1987, but that's because > there haven't been any good ones lately.) > > My winsome #1 daughter (who grew up with no TV in the house, courtesy of > her cruel and inhuman father) bought the Nth season of Rocky & > Bullwinkle on DVD, and I happened to pass by the room she was watching > it in. I always did like the Confederate Corrector episode. (And #2 > daughter is winsome too, in case she's reading this.) > > My kids also keep me in good reading material--on Sunday, when I was > getting ready to go on my monthly trip to NM, the same daughter gave me > a book on the Trojan War to read on the airplane, and my son gave me his > favourite Hemingway. > Which Hemingway was the favorite?
From: JosephKK on 30 Jul 2010 01:10 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. It's that simple. > >They taught us this our first freshman semister in EE school, in a >course called "Engineering Design Analysis" which was taught in a >small classroom by the Dean of Engineering, just to get us started on >the right track. It's been a great friend ever since. > >John So sorry that you had to wait to get dimensional analysis until college, i got it in my sohpmore year physics in high school.
From: JosephKK on 30 Jul 2010 02:00 On Thu, 29 Jul 2010 11:01:24 -0500, John Fields <jfields(a)austininstruments.com> wrote: >On Thu, 29 Jul 2010 07:06:50 -0700, John Larkin ><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > >>On Thu, 29 Jul 2010 06:13:05 -0700 (PDT), George Herold >><gherold(a)teachspin.com> wrote: > >>>(I'm just tired of the snipping back and forth... I should have just >>>kept my mouth shut and moved on.) >>> >>>George H. >>>> >>>> John- Hide quoted text - >>>> >>>> - Show quoted text - >> >>Just try injecting technical riffs - braininstorming in public - into >>the hen-clucking OT personal rants. Not only does that steer us back >>on topic, it annoys the hell out of some people who really deserve >>being annoyed. > >--- >Like this one?: > >I am so sick of grey, white, black, silver, and repulsive >pearl-colored cars. You can drive for blocks around here and see >nothing but asphalt-colored cars. When I saw that true-red Audi for >sale, I had to have it. > >That Mercedes is a decent shade of red, sort of arterial blood color. >I've started to see a few new cars on the street that are actual >colors, not just midnight blue or mud red, but *colors*. Maybe things >are turning around. > >Those Germans sure know how to make cars. 0-60 in 3.7 seconds isn't >bad at all. That's 0.75 Gs, if I did the math right. > >John > > >or this one?: > >Nobody is going to do anything serious about CO2. And maybe we >shouldn't anyhow. > >This is serious > >http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2010/07/28/MN5H1EK6BV.DTL > >and we *can* do something about it. > >John Given the well known issues with getting realistic data from SPICE which has well calibrated and tested models, do you really want to trust anybody making climate predictions with models whose very theory is suspect as well? Particularly when there is no track record of model testability or calibratability?
From: JosephKK on 30 Jul 2010 02:23
On Thu, 29 Jul 2010 07:14:56 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Thu, 29 Jul 2010 01:53:29 -0400, Phil Hobbs ><pcdhSpamMeSenseless(a)electrooptical.net> wrote: > >>Robert Baer wrote: >>> John Larkin wrote: >>>> On Wed, 28 Jul 2010 00:52:53 -0700, Robert Baer >>>> <robertbaer(a)localnet.com> wrote: >>>> >>>>> John Fields wrote: >>>>>> On Tue, 27 Jul 2010 07:01:58 -0700, John Larkin >>>>>> <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>>>>> >>>>>>> On Tue, 27 Jul 2010 04:00:22 -0500, John Fields >>>>>>> <jfields(a)austininstruments.com> wrote: >>>>>>> >>>>>>> >>>>>>>>> It has to do with >>>>>>>>> getting SI units right. Did you ever read the wiki piece on >>>>>>>>> dimensional analysis? Do you think it is smoke and mirrors? >>>>>>>>> >>>>>>>>> So, where did I say that charges can't generate forces? If you can't >>>>>>>>> find such a statement, YOU are the one with emotions clouding your >>>>>>>>> reason. >>>>>>>> --- >>>>>>>> Nonsense. >>>>>>>> >>>>>>>> All it means is that its location has slipped my mind, that the >>>>>>>> message has been deleted or, who knows??? >>>>>>> Who knows??? I know. You are deluded or just a liar. I would never say >>>>>>> anything so silly. >>>>>> --- >>>>>> You would, you have, and you will again, so you're the liar. >>>>>> >>>>>> "Latching relays have infinite gain." is a pretty silly thing to say, >>>>>> yes? >>>>>> >>>>>> >>>>>> JF >>>>> I think i "made a case" that the "gain" was not too hot, using >>>>> rough numbers for input power to switch states, and power handling >>>>> capability. >>>>> For an infinite "gain", either the power to switch states must be >>>>> zero, and/or the power handling capability must be infinite. >>>>> Clearly, NEITHER exists. >>>> >>>> Power gain is Pload/(Pcoil*DutyCycle), where Dutycycle is the fraction >>>> of time that the coil is energized. In plain English, power gain is >>>> averaged load power divided by averaged coil power. That has no upper >>>> bound as duty cycle approaches zero. In, say, a home thermostat that >>>> uses one AA battery, Dutycycle might be a few tens of PPM, which is >>>> why the battery will last a year or two. Probably the clock/LCD run >>>> the battery down more than the relay does. >>>> >>>> So the argument devolves to whether a number that is unboundedly large >>>> can be referred to as "infinite." Go for it. >>>> >>>> John >>>> >>>> >>> By your own statement, you admit that the duty cycle IS NOT ZERO, and >>> therefore there IS a bound. >>> And "duty cycle" does not cut it; if so, one could take a very large >>> (latching, if that "helps") relay and operate it *once* using its >>> required 200KW of power, to control one microwatt of load - and >>> "therefore" have an absurdly large "gain" based on the "duty cycle" of >>> almost zero. >>> >> >>The amount of bandwidth we've been wasting recently on exactifussitudes >>like this makes arguing about angels dancing on the head of a pin seem >>positively practical. >> >>Personally, I make an average of about six stupid mistakes before >>breakfast, so I'm used to it by now. Fields has a private meaning for >>the word 'force', and Larkin is using 'infinite' in a loose sense. > >As working engineers, we use a lot of terms in a loose sense. Like >charge, average, infinite, heat, "Gaussian", power factor, Q, >impedance, noise, exponential, "final", linear, all sorts of stuff >that's mathematically imprecise. Because it's good enough to make >things work. Somebody accused me here of not being a good scientist: >guilty! > >John It is nice to hear, but no one else here abuses that difference to the extent you do, not do many others claim to be so scientific in approach as you do. Grow up some, Mr. Businessman, and acknowledge what you have become really good at: the regular manufacture of test equipment at reasonable prices. |