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Re: creating gm/Id vs Id/W plot in ltspice
john23,
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FYI, in the plot you uploaded today, the lower plotted waveform is -D(Is(M1))/D(V(Vgs)).
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But the denominator is 1.0, because the X-axis is V4, and V4 directly controls V(Vgs).? So it can be eliminated.? Perhaps you did not understand how LTspice's derivative operator D() works.? It should not be written as D(y)/D(x).? It is normally written as just D(expression).? That expression alone takes the derivative of the quantity, with respect to the X-axis variable.
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Also it looks like you are confused about whether to plot the MOSFET's Source current or its Drain current.? Yes, they are almost the same magnitude with opposite polarity, so this is more a question of principle than of numerical error.
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Andy
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Re: Have anyone built black hole model already ?
¿ªÔÆÌåÓýWell, at first glance, not knowing quite what you¡¯re looking for,
? Dave ? From: [email protected] <[email protected]>
On Behalf Of ericsson.sunshine via groups.io
Sent: Wednesday, April 16, 2025 10:48 PM To: [email protected] Subject: EXTERNAL: Re: [LTspice] Have anyone built black hole model already ? ? Hi, boys & girls: ? I have tried this simulation for almost 7 years, but I still can't see the singularity, can you help to fix that ? In the time domain simulation , it didn't show the 'suck everything' effect as the image (someone have successfully seen that.) uploaded in the... ? ? The simulation file I have uploaded in temp,? (I take the risk of IT warning...) ? I can't believe it, 7 years, it took all my fun. ? Wish you all enable to enjoy your life as long as Nexperia possible. ? Best regards. |
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Re: creating gm/Id vs Id/W plot in ltspice
On Thu, Apr 17, 2025 at 10:44 AM, john23 wrote:
Well, as I said, you edited your .PLT file, which you should not have done.? Don't go there.? That would be like "the blind leading the blind".
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But I see this looks wrong:
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It says "traces: 1" but then it lists two traces.? That's a mistake.
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I'll say this once again:? Do not try hand-editing your .PLT file, in hopes that some magic will happen.? Magic usually does not happen.
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Figure out what you want to plot.
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Then set up the plots to give you that plot.
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So -- what exactly do you want to plot?
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Andy
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Re: creating gm/Id vs Id/W plot in ltspice
On Thu, Apr 17, 2025 at 10:35 AM, john23 wrote:
I strongly recommend that you do NOT ever edit your .PLT file.? That is not the way to change your LTspice plots.? It is too dangerous, for one thing.
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Instead, make the changes the normal way: by editing settings in the program (LTspice) itself.
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You told us that you are doing a .DC sweep, but that is not nearly enough information to give you sound advice.? Plus your questions are somewhat spread out over multiple topics and multiple simulations, and I find it difficult to track which one(s) you are talking about.? What EXACTLY are you trying to do, this time?? Did you follow Tony's [oops!] John Woodgate's advice earlier?? Did it work?? If it did not work, what happened instead?
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Sending us a screenshot of a simulation, as you have done this time, is absolutely unhelpful.? How does that screenshot relate to your question?? How can I simulate your screenshot on MY computer to help answer your question?
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And what is your objective, anyway?? You have lost me.
Andy ? |
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Re: creating gm/Id vs Id/W plot in ltspice
UPDATE:
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I tried to change the line as shown below ,However I get a bug saying I got extra curly braces.
Where did I go wrong? Thanks. ?
DC transfer characteristic] { ? ?Npanes: 2 ? ?{ ? ? ? traces: 1 {34668548,0,"Is(M1)"} ? ? ? X: (' ',1,0.01,0.2,1.8) ? ? ? Y[0]: ('?',1,0,8e-07,8e-06) ? ? ? Y[1]: ('_',0,1e+308,0,-1e+308) ? ? ? Amps: ('?',0,0,1,0,8e-07,8e-06) ? ? ? Log: 0 0 0 ? ?}, ? ?{ ? ? ? traces: 1 ?{34603010,0,"Id(M1)"} {524291,1,"d(Id(M1))/d(V(Vgs))"} ? ? ? X: (' ',1,0.01,0.2,1.8) ? ? ? Y[0]: ('?',0,0,1e-06,1.3e-05) ? ? ? Y[1]: ('_',0,1e+308,0,-1e+308) ? ? ? Units: "ohm-1" ('?',0,0,0,0,1e-06,1.3e-05) ? ? ? Log: 0 0 0 ? ?} } |
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Re: creating gm/Id vs Id/W plot in ltspice
Hello ,My original PLT file of the attached photo is shown below.
Where do I need to change this file ? and to what line do I need to change? Thanks. /g/LTspice/photo/294510/3906627?p=Created%2C%2C%2C20%2C2%2C0%2C0 [DC transfer characteristic] { ? ?Npanes: 2 ? ?{ ? ? ? traces: 1 {34668548,0,"Is(M1)"} ? ? ? X: (' ',1,0.01,0.2,1.8) ? ? ? Y[0]: ('?',1,0,8e-07,8e-06) ? ? ? Y[1]: ('_',0,1e+308,0,-1e+308) ? ? ? Amps: ('?',0,0,1,0,8e-07,8e-06) ? ? ? Log: 0 0 0 ? ?}, ? ?{ ? ? ? traces: 1 {524290,0,"-D(Is(M1))/D(V(Vgs))"} ? ? ? X: (' ',1,0.01,0.2,1.8) ? ? ? Y[0]: ('?',0,0,1e-06,1.3e-05) ? ? ? Y[1]: ('_',0,1e+308,0,-1e+308) ? ? ? Units: "ohm-1" ('?',0,0,0,0,1e-06,1.3e-05) ? ? ? Log: 0 0 0 ? ?} } |
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Re: Have anyone built black hole model already ?
On Thu, Apr 17, 2025 at 06:25 AM, Tony Casey wrote:
This is exactly the same phenomenon as with a spectrum analyser requiring slower sweep times as you narrow the resolution bandwidth to avoid spectrum distortion.Also known as (or a variation of) Heisenberg's Uncertainty Principle.? A trade-off between knowledge of time and knowledge of frequency.? Just an FYI. ?
Andy
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Re: Can't get to "Files" or "Photos" (was: LDMOS SPICE MODELS)
¿ªÔÆÌåÓýCollaboration Team, My apologies as I can now see the flow error.? This should be described so that others don¡¯t get stuck.? I made an account on groups.io and subscribed to the ltspice email list but did not add subscription to the LTspice group in group.io (bottom of page) and thus could see messages on the site but not change directories to files or photos. ? Matt ? From: [email protected] <[email protected]>
On Behalf Of Dave Wade via groups.io
Sent: Wednesday, April 16, 2025 8:19 PM To: [email protected] Subject: Re: [LTspice] Can't get to "Files" or "Photos" (was: LDMOS SPICE MODELS) ?
? On 16/04/2025 23:55, John Woodgate via groups.io wrote:
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Re: Have anyone built black hole model already ?
¿ªÔÆÌåÓýOn 17/04/2025 07:48, ericsson.sunshine
via groups.io wrote:
To see anything like the "black hole" singularity, you have increase the resolution. You have not specified the maximum time step. You also have to sweep the frequency very slowly because the higher the Q of the notch filter, the longer its settling time is. This is exactly the same phenomenon as with a spectrum analyser requiring slower sweep times as you narrow the resolution bandwidth to avoid spectrum distortion. -- Regards, Tony |
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Re: Can't get to "Files" or "Photos" (was: LDMOS SPICE MODELS)
¿ªÔÆÌåÓýThat's very good advice. It should be
archived. On 2025-04-17 00:18, Dave Wade via
groups.io wrote:
--
Best wishes John Woodgate RAYLEIGH Essex OOO-Own Opinions Only If something is true: * as far as we know - it's science *for certain - it's mathematics *unquestionably - it's religion |
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Re: Have anyone built black hole model already ?
Hi, boys & girls:
?
I have tried this simulation for almost 7 years, but I still can't see the singularity, can you help to fix that ?
In the time domain simulation , it didn't show the 'suck everything' effect as the image (someone have successfully seen that.) uploaded in the...
?
?
The simulation file I have uploaded in temp,?
(I take the risk of IT warning...)
?
I can't believe it, 7 years, it took all my fun.
?
Wish you all enable to enjoy your life as long as Nexperia possible.
?
Best regards. |
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Re: Can't get to "Files" or "Photos" (was: LDMOS SPICE MODELS)
¿ªÔÆÌåÓýOn 16/04/2025 23:55, John Woodgate via
groups.io wrote:
There are a few options. If you go to any page there is a log-in link top right. If you click that you get a page with various log-in options. I usually suggest that folks just use the "e-mail me a link to log-in" button. That takes you to a page where you can pop-in your email address. It then sends you a link that lets you login without a password.... No need to set or remember a password.. Dave G4UGM |
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Re: Can't get to "Files" or "Photos" (was: LDMOS SPICE MODELS)
On Wed, Apr 16, 2025 at 06:56 PM, John Woodgate wrote:
I think there is no need to do that.? I am 99% sure that you get directed immediately to the webpage to login, which makes it pretty obvious.
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I am confident that you did.? It's possible that you might not if you joined the group from the Web and provided a password at the same time.? I don't know if that is even possible.
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Re: Can't get to "Files" or "Photos" (was: LDMOS SPICE MODELS)
On Wed, Apr 16, 2025 at 06:20 PM, Tony Casey wrote:
I tried logging out of groups.io. None of the groups or their pages are accessible, either directly from a browser, or from a desktop URL link. Either option takes you straight to the login page. Well, it depends.
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When logged-out, you can get to any group at Groups.io that is set to Public.? But your options when logged-out are limited.? In the [LTspice] group, you can see the group's main webpage, and read Messages, but that is almost all you can do, without being logged-in.
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If you try to go directly to the URL for the group (/g/LTspice), it works and you go there.
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If you try to go directly to the URL for the Messages section (/g/LTspice/topics), or to any individual message, it works and you go there.
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If you try to go directly to the URL for the Files section (/g/LTspice/files) or the?Temp folder (/g/LTspice/files/Temp), apparently it redirects you straight to the Login page (not to /g/LTspice as I may have suggested earlier).? I don't know whether this is browser-specific.? It should not me.?
Helmut Sennewald set up this group so that Messages are public.? That means anyone in the universe can read them, even non-members who can't reply to them or send new messages.
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Andy
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Re: Can't get to "Files" or "Photos" (was: LDMOS SPICE MODELS)
¿ªÔÆÌåÓýI think it would be helpful to detail how to
do that log-in. I don't recall having to do it, but then my data
were transferred automagically from the old Yahoo group. On 2025-04-16 23:48, Andy I via
groups.io wrote:
n order to access all the group's web features from your web browser, you must (1) be a group member, and (2) be logged-in to your Groups.io account.? --
Best wishes John Woodgate RAYLEIGH Essex OOO-Own Opinions Only If something is true: * as far as we know - it's science *for certain - it's mathematics *unquestionably - it's religion |
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Re: Can't get to "Files" or "Photos" (was: LDMOS SPICE MODELS)
On Wed, Apr 16, 2025 at 06:41 PM, John Woodgate wrote:
There is no glitch.
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Matt is a group member.? That enables him to send and receive messages.? By email.
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But he can't access all of the group's website features until he logs-in to Groups.io with his web browser.
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Until he logs-in with his web browser, he can't access Files.? But he can send and receive messages.
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Andy
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Re: Can't get to "Files" or "Photos" (was: LDMOS SPICE MODELS)
On Wed, Apr 16, 2025 at 06:24 PM, Matthew D'Entremont wrote:
No, not right.? Please read carefully.?
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When you sign up for the LTspice group, you will be signed up to the LTspice group.? Period.? Being a group member means you are a group member and you can send messages to (and receive messages from) the group.? Via email.
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In order to access all the group's web features from your web browser, you must (1) be a group member, and (2) be logged-in to your Groups.io account.? Without the latter, you are still a group member, and you are still capable of sending and receiving messages via your email, but your web browser does not know that you are a group member, and neither do Groups.io's servers know that some random Chrome or Safari or Firefox browser is being operated by a group member.? You must, must, must sign-in to Groups.io with your web browser, in order to access the web features.
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When not signed-in with your browser:
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Andy
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Re: Can't get to "Files" or "Photos" (was: LDMOS SPICE MODELS)
¿ªÔÆÌåÓýThere appears to be a glitch somewhere,
because if you were not a member of the LTspice group, you could
not post messages: if you tried to do that, a message would be
sent to the moderators, asking for your membership to be
approved.? The membership list is open to the moderators,and you
are listed as an approved member. I just wonder if you are
trying to get access by using a different email address from the
one you have registered, which is Matthew.DEntremont [at] Dal.Ca On 2025-04-16 23:24, Matthew
D'Entremont via groups.io wrote:
--
Best wishes John Woodgate RAYLEIGH Essex OOO-Own Opinions Only If something is true: * as far as we know - it's science *for certain - it's mathematics *unquestionably - it's religion |