Bill Sloman wrote:> On Nov 7, 6:41 am, John S <Soph...@invalid.org> wrote: > >>On 11/4/2012 3:37 PM, Jamie wrote: > > > <snip> > >>> I just love those that talk shit and most likely hardly even touch a >>>piece of equipment. When they do I am sure they're all thumbs and >>>fingers with it and most likely end up getting some one else to do it >>>for them and take all the credit for it. >> >>Like you, right? People like you tend to join a crowd of similar people. >>That's why you are only tolerated here. Find your own crowd. >> >> >>> Those guilty of this need not to step forward, I already know who >>>most of you are. >> >>Of course. You are omnipotent. > > > I think you meant omniscient. Which Jamie may believe - but only > within the rather circumscribed universe of discourse - and the rest > of us know to be quite a way from the truth. > > -- > Bill Sloman, SydneySpeak for yourself, you hardly have enough energy in that singularity on your solders to think, let alone operate a keyboard and wipe your ass. You spend all your time searching the web for that black hole of yours to suck up in hopes that there is some shred of information you can use to mislead the public with great deception. Don't be including the general public in your punitive deceitful appearance. Many here don't know any better, they are simple minded sheep lost in the propaganda orchestrated by the likes of you. Jamie
Bifilar Wound Balun Transformer
Started by ●November 3, 2012
Reply by ●November 6, 20122012-11-06
Reply by ●November 6, 20122012-11-06
John S wrote:> On 11/5/2012 8:25 PM, Jamie wrote: > >> Bill Sloman wrote: >> >>> On Nov 6, 12:17 pm, John Larkin <jlar...@highlandtechnology.com> >>> wrote: >>> >>>> On Mon, 5 Nov 2012 14:40:55 -0800 (PST), Bill Sloman >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> <bill.slo...@ieee.org> wrote: >>>> >>>>> On Nov 5, 1:53 pm, John Larkin >>>>> <jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >>>>> >>>>>> On Sun, 4 Nov 2012 19:43:52 -0600, "Tim Williams" >>>>>> <tmoran...@charter.net> wrote: >>>>>> >>>>>>> "John Larkin" <jjlar...@highNOTlandTHIStechnologyPART.com> wrote in >>>>>>> messagenews:u2rd98l8ie7ucnfqk2em03grjthvdmoo1q@4ax.com... >>>> >>>> >>>>> <snip> >>>> >>>> >>>>>> That particular transformer in the photo was driven by a gaasfet. It >>>>>> worked fine, made really pretty isolated pulse outputs, about 500 ps >>>>>> edges. About 2000 of those transformers trigger most all the various >>>>>> gadgets at NIF. >>>> >>>> >>>>> But what's the inter-winding capacitance? I could probably work it >>>>> out, but you presumably know the exact number. >>>> >>>> >>>> It's just a few pF. The winding is just a few inches long. >>> >>> >>> >>> That's a "don't know". >>> >>> >>>>> Whatever it is, 2000 of it is going to be a lot of capacitance across >>>>> a galvanic isolation barrier. >>>> >>>> >>>> The 2000 outputs are separate triggers, "clients" (things that we >>>> trigger) scattered all over the site. The isolation is only to break >>>> ground loops and keep jitter down. >>> >>> >>> >>> Of course. But it's capacitance across a galvanic isolation barrier, >>> and - as such - injects AC current into the isolated ground. If your >>> clients aren't keeping track of that, they aren't doing their job >>> right. >>> >>> >>>> http://arxiv.org/ftp/physics/papers/0111/0111046.pdf >>>> >>>> (one of my very few published papers) >>> >>> >>> >>> 155.52-MHz seems surprisingly low. I would have thought that there >>> were faster standard frequencies that they might have adopted, with >>> correspondingly lower edge jitter. And it's not "your" paper - you >>> aren't first author, and clearly didn't write it. >>> >>> It may be one of the few published papers that list you as an author, >>> which is no small thing, but it's not "your" paper. >>> >>> -- >>> Bill Sloman, Sydney >> >> You're not racking up many points either. >> >> Jamie >> > > And you think you are? Go away and leave these professionals alone. At > least they understand the subject whereas you don't even know your job > function.Professionals? If you only knew what one was. Impersonation is more your style. Jamie
Reply by ●November 6, 20122012-11-06
John S wrote:> On 11/4/2012 3:24 PM, Jamie wrote: > >> John S wrote: >> >>> On 11/3/2012 10:25 PM, rickman wrote: >>> >>>> On 11/3/2012 9:42 PM, John Larkin wrote: >>>> >>>>> On Sat, 3 Nov 2012 20:40:37 -0500, "Tim Williams" >>>>> <tmoranwms@charter.net> wrote: >>>>> >>>>>> "John Larkin"<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in >>>>>> message news:ffcb985qk94e0cf265odu97o95d90sp1bh@4ax.com... >>>>>> >>>>>>> We do exactly that in a bunch of products, namely use the shield >>>>>>> as a >>>>>>> primary winding and the inner as the fully isolated secondary of a >>>>>>> transformer. We do 1:1 and 1:2 (voltage step up) at levels from 5 >>>>>>> volts to over 100. >>>>>>> >>>>>>> https://dl.dropbox.com/u/53724080/Circuits/Xfmrs.JPG >>>>>>> >>>>>>> This makes a transformer with very low leakage inductance, so we get >>>>>>> sub-ns rise times into a 50 ohm load. >>>>>> >>>>>> >>>>>> >>>>>> Except that, as I said, the leakage is not particularly low. One >>>>>> gets >>>>>> better performance in that regard from, say, copper foil pairs >>>>>> (which, >>>>>> ultimately, is still doing the same thing, but with a low impedance >>>>>> symmetrical stripline, not 50 ohm coax). Which is often done in >>>>>> power >>>>>> circuitry. But "very low leakage" is not what you're going for, so >>>>>> it's >>>>>> best not to claim that's what you're doing. >>>>>> >>>>>> Tim >>>>> >>>>> >>>>> >>>>> But it works. >>>> >>>> >>>> >>>> See, this is the sort of stuff that, if I were a potential customer, >>> >>> >>> >>> Well, apparently you're not. >>> >>>> would turn me off to doing business with you. >>> >>> >>> >>> Oops! One potential customer lost! Damn, John, this will put you out >>> of business. >>> >>> >>> Geeze, if I am talking to >>> >>>> someone about what is going on in a system and they say to me, "but it >>>> works", I would think they didn't understand it at all. >>> >>> >>> >>> Maybe the foot is on the other shoe. Maybe you didn't understand it at >>> all. >>> >>>> Do you not see how your posts make you look? >>>> >>>> Rick >>> >>> >>> >>> And you understand how your posts look? That's curious. >>> >>> >> Those that don't know shit, should shit elsewhere ! Get it? > > > Yeah. Okay. Keep your mouth open. >After you imbecile. Jamie
Reply by ●November 6, 20122012-11-06
Bill Sloman wrote:> On Nov 6, 2:25 pm, John Larkin > <jjlar...@highNOTlandTHIStechnologyPART.com> wrote: > >>On Mon, 5 Nov 2012 18:11:07 -0800 (PST), Bill Sloman >><bill.slo...@ieee.org> wrote: >> >>>On Nov 6, 12:17 pm, John Larkin <jlar...@highlandtechnology.com> >>>wrote: >>> >>>>On Mon, 5 Nov 2012 14:40:55 -0800 (PST), Bill Sloman >>>><bill.slo...@ieee.org> wrote: >>>> >>>>>On Nov 5, 1:53 pm, John Larkin >>>>><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >>>>> >>>>>>On Sun, 4 Nov 2012 19:43:52 -0600, "Tim Williams" >>>>>><tmoran...@charter.net> wrote: >>>>>> >>>>>>>"John Larkin" <jjlar...@highNOTlandTHIStechnologyPART.com> wrote in >>>>>>>messagenews:u2rd98l8ie7ucnfqk2em03grjthvdmoo1q@4ax.com... >> >>>>><snip> >> >>>>>>That particular transformer in the photo was driven by a gaasfet. It >>>>>>worked fine, made really pretty isolated pulse outputs, about 500 ps >>>>>>edges. About 2000 of those transformers trigger most all the various >>>>>>gadgets at NIF. >> >>>>>But what's the inter-winding capacitance? I could probably work it >>>>>out, but you presumably know the exact number. >> >>>>It's just a few pF. The winding is just a few inches long. >> >>>That's a "don't know". >> >>>>>Whatever it is, 2000 of it is going to be a lot of capacitance across >>>>>a galvanic isolation barrier. >> >>>>The 2000 outputs are separate triggers, "clients" (things that we >>>>trigger) scattered all over the site. The isolation is only to break >>>>ground loops and keep jitter down. >> >>>Of course. But it's capacitance across a galvanic isolation barrier, >>>and - as such - injects AC current into the isolated ground. >> >>Ground loops are usually low frequencies, like 60 Hz. > > > 50Hz in some countries, 400Hz in aircraft. However circulating current > at an unusual frequency can create problems too. > > >>If your >> >>>clients aren't keeping track of that, they aren't doing their job >>>right. >> >>My clients do their jobs right, and so do I. > > > So you tell us. You presumably convinced them of your competence, or > maybe you were just the low bidder. > > >>You don't have a job. > > > What's that got to do with their competence? Or yours for that matter? > > >>>>http://arxiv.org/ftp/physics/papers/0111/0111046.pdf >> >>>>(one of my very few published papers) >> >>>155.52-MHz seems surprisingly low. I would have thought that there >>>were faster standard frequencies that they might have adopted, with >>>correspondingly lower edge jitter. And it's not "your" paper - you >>>aren't first author, and clearly didn't write it. >> >>>It may be one of the few published papers that list you as an author, >>>which is no small thing, but it's not "your" paper. >> >>My timing modules work; you don't. > > > You claim ownership of a paper of which you were a minor author. > Should we trust your claims about your timing modules? > > -- > Bill Sloman, Sydney >Just for you slow-man. http://www.youtube.com/watch?v=s8zn63ADiIE Jamie
Reply by ●November 6, 20122012-11-06
On Tue, 6 Nov 2012 15:26:09 -0800 (PST), Bill Sloman <bill.sloman@ieee.org> wrote:>On Nov 7, 2:06�am, John Larkin ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >> On Tue, 6 Nov 2012 00:36:11 -0800 (PST), Bill Sloman >> <bill.slo...@ieee.org> wrote: >> >On Nov 6, 2:25 pm, John Larkin >> ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >> >> On Mon, 5 Nov 2012 18:11:07 -0800 (PST), Bill Sloman >> >> <bill.slo...@ieee.org> wrote: >> >> >On Nov 6, 12:17 pm, John Larkin <jlar...@highlandtechnology.com> >> >> >wrote: >> >> >> On Mon, 5 Nov 2012 14:40:55 -0800 (PST), Bill Sloman >> >> >> <bill.slo...@ieee.org> wrote: >> >> >> >On Nov 5, 1:53 pm, John Larkin >> >> >> ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >> >> >> >> On Sun, 4 Nov 2012 19:43:52 -0600, "Tim Williams" >> >> >> >> <tmoran...@charter.net> wrote: >> >> >> >> >"John Larkin" <jjlar...@highNOTlandTHIStechnologyPART.com> wrote in >> >> >> >> >messagenews:u2rd98l8ie7ucnfqk2em03grjthvdmoo1q@4ax.com... > ><snip> > >> >> My clients do their jobs right, and so do I. >> >> >So you tell us. �You presumably convinced them of your competence, or >> >maybe you were just the low bidder. >> >> >>You don't have a job. >> >> >What's that got to do with their competence? Or yours for that matter? >> >> >> >>http://arxiv.org/ftp/physics/papers/0111/0111046.pdf >> >> >> >> (one of my very few published papers) >> >> >> >155.52-MHz seems surprisingly low. I would have thought that there >> >> >were faster standard frequencies that they might have adopted, with >> >> >correspondingly lower edge jitter. And it's not "your" paper - you >> >> >aren't first author, and clearly didn't write it. >> >> >> >It may be one of the few published papers that list you as an author, >> >> >which is no small thing, but it's not "your" paper. >> >> >> My timing modules work; you don't. >> >> >You claim ownership of a paper of which you were a minor author. >> >Should we trust your claims about your timing modules? >> >> Why would I care what you trust? Do you think the NIF paper was faked? > >It seems most unlikely, but - accepting that the paper is honest - >which I'm more than happy to do - all it says is that you were the >supplier, and your gear worked well enough to be satisfactory in the >application.What more can one expect in life, but to do good work, to build things, and, with luck, be appreciated for it?> >As you have mentioned here, when physicists publish about electronics, >they usually have exaggerated ideas about how good their electronics >is and how close it is to the state of the art. I've got a couple of >comments in Review of Scientific Instruments that criticise >particularly flagrant examples of this kind of defect. > >> We did two systems for NIF, got some awards, made some money, learned >> an awful lot. That's what sometimes happens whan you DO stuff. > >I've noticed. That's one of the reasons why I'd like to do some more >stuff, and why I'm frustrated by being confined to doing stuff I can >afford which solves the kinds of problems that I can dream up without >much help from the outside world. I learned a great deal when I was >working on the Cambridge Instruments Electron Beam Tester, and I >enjoyed the process.I think you could find companies that need someone who can understand their science and help them with the electronics. There's a lot of scientific gear out there that, as Phil says, needlessly throws away 30 dB of performance. (Remember the insane FTMS preamp I posted about here? Down 30 dB, but still better than Brand B, who tossed 40 dB.) It wouldn't be very hard to explore that possibility. It would be fun. -- John Larkin Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation
Reply by ●November 6, 20122012-11-06
On Tue, 6 Nov 2012 15:29:35 -0800 (PST), Bill Sloman <bill.sloman@ieee.org> wrote:>On Nov 7, 8:23�am, John Larkin <jlar...@highlandtechnology.com> wrote: >> On Sun, 04 Nov 2012 19:49:14 +0100, Fred Bartoli <" "> wrote: >> >> >> >> >> >> >> >> >> >> >John Larkin a crit : >> >> On Sun, 04 Nov 2012 18:57:27 +0100, Fred Bartoli <" "> wrote: >> >> >>> Fred Abse a crit : >> >>>> On Sat, 03 Nov 2012 18:50:54 -0500, Tim Williams wrote: >> >> >>>>> The important thing about transmission line transformers is to forget >> >>>>> about using them as transformers. �Use them as transmission lines! >> >>>> Anybody know how to accurately model a transmission line transformer in >> >>>> Spice, taking into account core properties? >> >> >>> For a simple one, just as it is: >> >>> use a TLine/RLC tline and between the 2 ""shield/ref plane" connections >> >>> you just tie the magnetizing inductance, with maybe your core model >> >>> (losses, non linearities, hysteresis,...) >> >> >> What's interesting about the LT Spice transmission lines is that they >> >> have no common-mode DC continuity between ends. They act as if there >> >> is an ideal 1:1 isolation transformer in the circuit. >> >> >> That sort of makes sense, since, say, the outer conductor of a coax >> >> has its own complex impedance against the universe, and Spice elects >> >> to not model that. Still, it can throw you if you don't know about it, >> >> and make baluns seem to work much better than they will in real life. >> >> >If you want to accurately model a coax cable you need two TLines. One >> >modeling the center/shield transmission line, and a second one to model >> >the shield WRT to "space". >> >> >> So a txline can make a handy 1:1 ideal transformer. Unlike a 1:1 VCVS, >> >> it's bidirectional and the output loads the input. >> >> >The "standard" perfect transformer is composed of a vcvs to transport >> >voltage to the secondary and a CCCS to reflect the secondary current >> >back to the primary, and a 0 voltage source to probe it. >> >It is much less computationally demanding than the Tline which has to >> >maintain history. >> >> I guess there's nothing stopping one from making a couple of gigahenry >> inductors coupled with K=1. > >That's the joy of simulation. You can test ideas that would cost a >mint in superconducting wire and liquid helium if you wanted to try >them out on the bench. > >The are applications where that kind of expenditure on real parts >might be justifiable.It's cool to stick a micro-ohm resistor somewhere in a circuit to sample current, and follow that with a 1e6 gain amp with infinite CMRR. I like to build analog error computers into my circuits too, so I can graph error or goodness on the same plot as actual signals. I do tend to worry about power dissipation and real-world stuff in sims, where it just doesn't matter. A couple of 1 ohm resistors make a good divider, but I worry about the current, so I use 1Ks. -- John Larkin Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation
Reply by ●November 6, 20122012-11-06
John Larkin a �crit :> On Tue, 6 Nov 2012 15:29:35 -0800 (PST), Bill Sloman > <bill.sloman@ieee.org> wrote: > >> On Nov 7, 8:23 am, John Larkin <jlar...@highlandtechnology.com> wrote: >>> On Sun, 04 Nov 2012 19:49:14 +0100, Fred Bartoli <" "> wrote: >>> >>> >>> >>> >>> >>> >>> >>> >>> >>>> John Larkin a crit : >>>>> On Sun, 04 Nov 2012 18:57:27 +0100, Fred Bartoli <" "> wrote: >>>>>> Fred Abse a crit : >>>>>>> On Sat, 03 Nov 2012 18:50:54 -0500, Tim Williams wrote: >>>>>>>> The important thing about transmission line transformers is to forget >>>>>>>> about using them as transformers. Use them as transmission lines! >>>>>>> Anybody know how to accurately model a transmission line transformer in >>>>>>> Spice, taking into account core properties? >>>>>> For a simple one, just as it is: >>>>>> use a TLine/RLC tline and between the 2 ""shield/ref plane" connections >>>>>> you just tie the magnetizing inductance, with maybe your core model >>>>>> (losses, non linearities, hysteresis,...) >>>>> What's interesting about the LT Spice transmission lines is that they >>>>> have no common-mode DC continuity between ends. They act as if there >>>>> is an ideal 1:1 isolation transformer in the circuit. >>>>> That sort of makes sense, since, say, the outer conductor of a coax >>>>> has its own complex impedance against the universe, and Spice elects >>>>> to not model that. Still, it can throw you if you don't know about it, >>>>> and make baluns seem to work much better than they will in real life. >>>> If you want to accurately model a coax cable you need two TLines. One >>>> modeling the center/shield transmission line, and a second one to model >>>> the shield WRT to "space". >>>>> So a txline can make a handy 1:1 ideal transformer. Unlike a 1:1 VCVS, >>>>> it's bidirectional and the output loads the input. >>>> The "standard" perfect transformer is composed of a vcvs to transport >>>> voltage to the secondary and a CCCS to reflect the secondary current >>>> back to the primary, and a 0 voltage source to probe it. >>>> It is much less computationally demanding than the Tline which has to >>>> maintain history. >>> I guess there's nothing stopping one from making a couple of gigahenry >>> inductors coupled with K=1. >> That's the joy of simulation. You can test ideas that would cost a >> mint in superconducting wire and liquid helium if you wanted to try >> them out on the bench. >> >> The are applications where that kind of expenditure on real parts >> might be justifiable. > > It's cool to stick a micro-ohm resistor somewhere in a circuit to > sample current, and follow that with a 1e6 gain amp with infinite > CMRR. > > I like to build analog error computers into my circuits too, so I can > graph error or goodness on the same plot as actual signals. > > I do tend to worry about power dissipation and real-world stuff in > sims, where it just doesn't matter. A couple of 1 ohm resistors make a > good divider, but I worry about the current, so I use 1Ks. > >On complex designs (well simulations) it's better to worry about matrix conditioning and in this regards a 0V voltage source and a CCVS in lieu of your 1�ohm and 1E6 gain VCVS is much better. I have some applications where convergence is sometimes hard to obtain and I sure wouldn't want to make the situation worse than it needs to be. -- Thanks, Fred.
Reply by ●November 6, 20122012-11-06
John Larkin wrote:> On Tue, 6 Nov 2012 15:29:35 -0800 (PST), Bill Sloman > <bill.sloman@ieee.org> wrote: > >>>I guess there's nothing stopping one from making a couple of gigahenry >>>inductors coupled with K=1. >> >>That's the joy of simulation. You can test ideas that would cost a >>mint in superconducting wire and liquid helium if you wanted to try >>them out on the bench. >> >>The are applications where that kind of expenditure on real parts >>might be justifiable. > > > It's cool to stick a micro-ohm resistor somewhere in a circuit to > sample current, and follow that with a 1e6 gain amp with infinite > CMRR. >Micro ohms?, we use micro ohms for measuring current but they are kind of large in mass. Or are we not talking about copper? Jamie
Reply by ●November 6, 20122012-11-06
On Wed, 07 Nov 2012 02:30:01 +0100, Fred Bartoli <" "> wrote:>John Larkin a �crit : >> On Tue, 6 Nov 2012 15:29:35 -0800 (PST), Bill Sloman >> <bill.sloman@ieee.org> wrote: >> >>> On Nov 7, 8:23 am, John Larkin <jlar...@highlandtechnology.com> wrote: >>>> On Sun, 04 Nov 2012 19:49:14 +0100, Fred Bartoli <" "> wrote: >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>>> John Larkin a crit : >>>>>> On Sun, 04 Nov 2012 18:57:27 +0100, Fred Bartoli <" "> wrote: >>>>>>> Fred Abse a crit : >>>>>>>> On Sat, 03 Nov 2012 18:50:54 -0500, Tim Williams wrote: >>>>>>>>> The important thing about transmission line transformers is to forget >>>>>>>>> about using them as transformers. Use them as transmission lines! >>>>>>>> Anybody know how to accurately model a transmission line transformer in >>>>>>>> Spice, taking into account core properties? >>>>>>> For a simple one, just as it is: >>>>>>> use a TLine/RLC tline and between the 2 ""shield/ref plane" connections >>>>>>> you just tie the magnetizing inductance, with maybe your core model >>>>>>> (losses, non linearities, hysteresis,...) >>>>>> What's interesting about the LT Spice transmission lines is that they >>>>>> have no common-mode DC continuity between ends. They act as if there >>>>>> is an ideal 1:1 isolation transformer in the circuit. >>>>>> That sort of makes sense, since, say, the outer conductor of a coax >>>>>> has its own complex impedance against the universe, and Spice elects >>>>>> to not model that. Still, it can throw you if you don't know about it, >>>>>> and make baluns seem to work much better than they will in real life. >>>>> If you want to accurately model a coax cable you need two TLines. One >>>>> modeling the center/shield transmission line, and a second one to model >>>>> the shield WRT to "space". >>>>>> So a txline can make a handy 1:1 ideal transformer. Unlike a 1:1 VCVS, >>>>>> it's bidirectional and the output loads the input. >>>>> The "standard" perfect transformer is composed of a vcvs to transport >>>>> voltage to the secondary and a CCCS to reflect the secondary current >>>>> back to the primary, and a 0 voltage source to probe it. >>>>> It is much less computationally demanding than the Tline which has to >>>>> maintain history. >>>> I guess there's nothing stopping one from making a couple of gigahenry >>>> inductors coupled with K=1. >>> That's the joy of simulation. You can test ideas that would cost a >>> mint in superconducting wire and liquid helium if you wanted to try >>> them out on the bench. >>> >>> The are applications where that kind of expenditure on real parts >>> might be justifiable. >> >> It's cool to stick a micro-ohm resistor somewhere in a circuit to >> sample current, and follow that with a 1e6 gain amp with infinite >> CMRR. >> >> I like to build analog error computers into my circuits too, so I can >> graph error or goodness on the same plot as actual signals. >> >> I do tend to worry about power dissipation and real-world stuff in >> sims, where it just doesn't matter. A couple of 1 ohm resistors make a >> good divider, but I worry about the current, so I use 1Ks. >> >> > >On complex designs (well simulations) it's better to worry about matrix >conditioning and in this regards a 0V voltage source and a CCVS in lieu >of your 1�ohm and 1E6 gain VCVS is much better. >I have some applications where convergence is sometimes hard to obtain >and I sure wouldn't want to make the situation worse than it needs to be.Spice is all double floats, no? 1e6 isn't a very big number. A current sampler is open-loop so won't have convergence problems. LT Spice sometimes does weird things with time steps, especially if a circuit has radically different time constants here and there, or mysterious stuff inside a part model. Real transistors seem to stress it, too. Somebody should write a book or article about all that. -- John Larkin Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation
Reply by ●November 6, 20122012-11-06
On Tue, 06 Nov 2012 20:31:14 -0500, Jamie <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:>John Larkin wrote: > >> On Tue, 6 Nov 2012 15:29:35 -0800 (PST), Bill Sloman >> <bill.sloman@ieee.org> wrote: >> >>>>I guess there's nothing stopping one from making a couple of gigahenry >>>>inductors coupled with K=1. >>> >>>That's the joy of simulation. You can test ideas that would cost a >>>mint in superconducting wire and liquid helium if you wanted to try >>>them out on the bench. >>> >>>The are applications where that kind of expenditure on real parts >>>might be justifiable. >> >> >> It's cool to stick a micro-ohm resistor somewhere in a circuit to >> sample current, and follow that with a 1e6 gain amp with infinite >> CMRR. >> > Micro ohms?, we use micro ohms for measuring current but they are kind >of large in mass. Or are we not talking about copper? > >JamieSpice makes great micro-ohm resistors somehow! We do make our own current shunts, punched or photoetched from rolled manganin, but generally in the milli-ohms. -- John Larkin Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation
