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Re: Current Sensor
--- In LTspice@..., "danfly09" <da.nc3262@...> wrote:
I'm looking for a hall effect current sensor like the ACS712. You are in luck. Here is a subcircuit I made, but you will have to make your own symbol for it. Change the gain parameter to corresponding to the dash number of interest. -- a.s. .subckt ACS712 I+ I- Filter Out V+ V- .param gain=185m; 185m -05B, 100m -20A, 66m -30A V1 I+ I- 0 F1 V- 2 V1 {gain} T1 1 V- 2 V- Td=1u Zo=1 R1 2 V- 1 R2 Filter 2 1k7 G1 V- 3 Filter V- 1 C1 3 V- 1?3 Rpar=1 R3 Out 3 50 G2 V- 3 V+ V- 0.5 R4 V+ V- 2k .ends ACS712 |
Re: General SPICE environment setup
Lewis
For those wishing to create 'permanent' LTspice parts that appear in
your drop down menu of LTspice, please reference Adding a component to LTspice - Ltwiki.org <; ice> and a section on already completed parts following this approach at Components Library - LTwiki <> Further contributions to this library are welcomed, as well. This approach has also already been included in the messages here over the years, so I won't repeat it now. It's a little different that what is called out for in scad3.pdf. These parts are portable, but you must be aware of what the symbol and subcircuit names are, that you put in a folder of the \sym directory and \sub directory. I personally add a folder below the \sym directory for my own permanent parts. Then I make subcircuit names that are easily recognizable to sync to my other computers using LTspice. To make these parts portable, and part of any design you'd want to share, just include those specified sym and sub files in the same folder (all zipped together) as your shared schematic. The receiver can keep these in the same folder as the provided schematic and all goes on as before. Alternately, they can copy these provided symbols and subcircuits to their respective folders as outlined in the wiki, and they will become their own custom permanent parts. (You must restart LTspice to see them.) Sometimes, when exchanging schematics between my desktop and laptop I'll get a little sloppy and forget I'd used one of my permanent parts. So, LTspice tells me if I try to do an analysis. The bigger embarrassment is to professionally provide a schematic, or upload on to this group - just to have it be incomplete. I hate to elaborate on this topic, as everyone here as justified strong opinions about it. But you asked - and here is my complete answer. --- In LTspice@..., eaneonakis@... wrote: not such a bad idea. Best Regardswrote:
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Re: Time varying coupling coefficient for 2 inductors
Ganesan
I forgot to add..
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The flux doesn't collapse instantaneously... This can be modeled by putting V(X) through an RC low pass. Cheers AG On 9/16/2011 5:55 PM, Ganesan wrote:
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Re: Time varying coupling coefficient for 2 inductors
Ganesan
I have modeled an ideal transformer with time varying coupling
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coefficient.. File is in Temp--> Non_ideal_transformer.asc <> Your feedback will be appreciated. Cheers A. Ganesan On 9/16/2011 11:02 AM, ttakeshian wrote:
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Re: Current Sensor
Google is your friend. Search on the phrase "spice hall effect"
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Howard On 9/16/2011 4:39 PM, danfly09 wrote:
Hi, i'm looking for a hall effect current sensor like the asc712... there isn't a .lib that i could simulate?? or anything possible solution but without use a shunt resistor |
Re: Ideal Swich Model missing
Another problem with the LTspice Help, is that just about everything
starts with the old non-graphical input format of traditional (i.e. Berkeley) SPICE: Syntax: Sxxx n1 n2 nc+ nc- <model> [on,off]And then we tell everyone to use the schematic editor, and upload schematic files instead of netlists. So the Help file is a little like using DOS in a Windows world. Plus the references to a SPICE "deck", a model "card", etc. Imagine if the Help for MS-Windows gave everything in terms of DOS commands and command-line switches. It probably makes little sense to anyone coming to LTspice for the first time. For those of us who used SPICE before, the relationship between the element and the model, by way of the model name, was obvious. And we take for granted that the element is now a schematic symbol, but the model is a "SPICE directive" ... which is mentioned in the Help description but not really explained. So yes, there are lots of problems. Andy |
Re: Time varying coupling coefficient for 2 inductors
--- In LTspice@..., "ttakeshian" <ttakeshian@...> wrote:
Tony, LTspice can be used to model any system of ordinary (not partical) differential equations using "analog computer" techniques. The coefficients can be made time varying by using BV elements that are a function of time. Rick |
Re: Ideal Swich Model missing
John Woodgate
In message <j50avg+6kln@...>, dated Fri, 16 Sep 2011, analogspiceman <analogspiceman@...> writes:
Well, in the switch example, Help offered,I would add a few more words. 'Open the downloaded LTspiceIV folder, open examples and then Educational, and open the schematic file Vswitch.asc'.... In doing that, I've assumed no more than beginner level understanding of Windows (at least in English) as well. That dot in .\examples\Educational\Vswitch.aschides a lot of meaning. It would certainly have minimised doubt anyway, but I agree with you that 'card' [and 'deck'] are archaisms that should be eliminated. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK When I point to a star, please look at the star, not my finger. The star will be more interesting. |
Re: Ideal Swich Model missing
--- In LTspice@..., John Woodgate wrote:
A constructive, serious answer! Thank you. [Y]ou have initially to forget all you know about the product,This much I already supposed, but the reemphasis is appreciated. Looking back at the original poster's difficulty in processing this sentence from Help, "A model card is required to define the behavior of the switch.", which to me clearly indicates that the user must create a model statement in which he assigns values to the switch parameters. Also implied is that this model statement is usually created in the form of a SPICE text directive and placed upon the schematic. A complete novice probably wouldn't know this without an example or pouring over the manual (which I did when I was brand new to LTspice, by the way). Also the sentence refers to a model card, which is most likely a meaningless term to those who weren't around in the days of punch card input (I wish Mike would expunge that term from any and all non-historical documentation). Still, these shortcomings would be overcome and answered by an example, a link to which Help *did* provide in this case. For each question, you then 'switch on' ONLY that part of yourThis is really good advice, as it would tend to overcome the problems from reading comprehension and information overload that were mentioned earlier. I wonder if this technique can be done in a way that is compatible with Help remaining an efficient reference manual. Anyway, thanks for the idea. Hundreds of questions are likely to be required. The limitedTrue, but a well done wiki could offer unlimited possibilities, both in links and graphics. Answers should include examples wherever possible.Well, in the switch example, Help offered, "See the schematic file .\examples\Educational\Vswitch.asc to see an example of a model card placed directly on a schematic as a SPICE directive.", which the original poster seemed not to have read (or at least ignored, hence my legitimate question about the possibility of there being either a reading comprehension problem or laziness at play). Note that this example would have answered any lingering questions about what "a model card" could mean. Regards -- analogspiceman |
Re: Ideal Swich Model missing
John Woodgate
In message <075FBDBF-7FC5-4AE8-921F-42D73C76DF0D@...>, dated Fri, 16 Sep 2011, Jim Wagner <wagnerj@...> writes:
As a further example, there is not a single screen snapshot in the whole documentation.I found several. 'Adding attributes', 'Adding the pins' and 'Attached cursors', for example, all include graphics if not exactly screen-shots. 'Colour palette editor' is another. It just says "do this... " or "do that...". For MANY people, that is simply not sufficient. That is not the way that many people learn.Agreed; it's not always the best way to communicate. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK When I point to a star, please look at the star, not my finger. The star will be more interesting. |
Re: Ideal Swich Model missing
John Woodgate
In message <744FF547-789E-48F5-9AE6-A4FF04DCCB25@...>, dated Fri, 16 Sep 2011, Jim Wagner <wagnerj@...> writes:
As far as I can see, "constructive criticism" does no good. The documentation appears to be the sole perview of Mike and it will be what he wants it to be.Mike obviously has a responsibility to ensure that the Help is completely accurate. But to extend that to saying that no improvement will be entertained is not justified. By no means. Simply don't accept the 'shoot down'. You can write, if you choose, your own 'Jim's Guide to LTspice' and put it on your web site or even in the Files or Files -> Tut folders on the list's web site. If so, it needs to be fixed. Now, that is NOT a constructive criticism. I hope this message will de-frustrate you, at least a bit. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK When I point to a star, please look at the star, not my finger. The star will be more interesting. |
Re: Ideal Swich Model missing
Jim Wagner
On Sep 16, 2011, at 11:12 AM, John Woodgate wrote:
In message <j500ob+lpdp@...>, dated Fri, 16 Sep 2011,As a further example, there is not a single screen snapshot in the whole documentation. It just says "do this... " or "do that...". For MANY people, that is simply not sufficient. That is not the way that many people learn. Another example: the documentation has few REAL examples. Step-by- step, picture-by-picture, of how you add a model, or a sub-circuit. Again, words are fine, words are necessary, but words are not sufficient. Jim Wagner Oregon Research Electronics [Non-text portions of this message have been removed] |
Re: Ideal Swich Model missing
Jim Wagner
On Sep 16, 2011, at 10:24 AM, analogspiceman wrote:
--- In LTspice@..., John Woodgate wrote:As far as I can see, "constructive criticism" does no good. The--- In LTspice@..., analogspiceman wrote:Well, people keeping complaining about Help, but so far no one,How to make Help continue to function as a compact and efficientThis is, in my experience, a problem with ALL Helps. I could write documentation appears to be the sole perview of Mike and it will be what he wants it to be. End of story. I have offered several positive suggestions about documentation improvement, including the "go check PSpice documentation, its mostly the same" and put what needs to be put into single document. That was shot down by you and others. So, what else is one to do? I would be delighted to contribute to the Wiki, but its not clear how. The front page of the Wiki says "create an account to contribute" but there is no link or information about creating an "account". Clearly,j genuine input is not wanted. Jim Wagner Oregon Research Electronics [Non-text portions of this message have been removed] |
Re: Ideal Swich Model missing
John Woodgate
In message <j500ob+lpdp@...>, dated Fri, 16 Sep 2011, analogspiceman <analogspiceman@...> writes:
Well, people keeping complaining about Help, but so far no one, including the complainers, has been willing or able to offer any concrete constructive criticism. It remains a puzzle. -- a.s.It needs a complete re-write, but the necessary combination of skills is extremely rare - a way to put over intricate concepts in simple language AND a deep understanding of LTspice. I have had some success in the first, but I am nowhere in the second. To do the first, you have initially to forget all you know about the product, program or application and consider ONLY what questions the user is likely to ask. For each question, you then 'switch on' ONLY that part of your product knowledge needed to answer the question. If you feel compelled to add more, formulate another question to introduce the addition. Hundreds of questions are likely to be required. The limited lists of up to 20 or so, offered by Microsoft and other Helps, are pitifully inadequate. Answers should include examples wherever possible. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK When I point to a star, please look at the star, not my finger. The star will be more interesting. |
Re: Ideal Swich Model missing
--- In LTspice@..., John Woodgate wrote:
--- In LTspice@..., analogspiceman wrote: Well, people keeping complaining about Help, but so far no one,How to make Help continue to function as a compact and efficientThis is, in my experience, a problem with ALL Helps. I could write including the complainers, has been willing or able to offer any concrete constructive criticism. It remains a puzzle. -- a.s. |
Re: Time varying coupling coefficient for 2 inductors
--- In LTspice@..., Tony "ttakeshian" wrote:
I need to model the coupling coefficient of two inductors asAs you have noted, K must be a fixed value. However, LTspice includes a behavioral inductor that may be a function of time. I suppose you could set up a T-network of three such inductors to vary with time the percentage of inductance shared between each side of the "T" while keeping the total inductance "seen" from each side fixed (this is what K effectively does). If you require other than a one-to-one turns ration, you could add an ideal transformer to one side of the T. -- a.s. PS: The behavioral inductor is well described in Help and in the many examples available here in the group archive, both in past messages and in files posted. |
Re: Ideal Swich Model missing
John Woodgate
In message <j4vu3g+ano2@...>, dated Fri, 16 Sep 2011, analogspiceman <analogspiceman@...> writes:
How to make Help continue to function as a compact and efficient reference while also being able to effectively provide answers that neophytes can actually see, process and put to use?This is, in my experience, a problem with ALL Helps. I could write a 3-screen post but I won't. It's a good PhD project on communication for someone. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK When I point to a star, please look at the star, not my finger. The star will be more interesting. |
Re: Freqeucny Dependent resistor
An emphatic yes. In one of my courses, Network Synthesis, one learns that for minimum phase networks (no zeros in the right half plane), the phase response of the network can be determined from the magnitude frequency response. As to A.S.'s remarks, I do not believe you have a physically realizable circuit by replacing a Laplace transform by its magnitude response. Complex poles and zeros need to occur in pairs in order for the time function to be a real valued function -- and to have a physically realizable circuit.
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Hubert ----- Original Message -----
From: John Fields To: LTspice@... Sent: Thursday, September 15, 2011 4:38 PM Subject: Re: [LTspice] Re: Freqeucny Dependent resistor On Thu, 15 Sep 2011 13:20:01 -0700, you wrote: >I believe it is impossible to have a physically realizable resistor that is frequency >dependent and has no reactive component. --- Carbon button microphone? -- JF |
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