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Re: A Huge Glitch
Hello Andy:
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A glitch is an unwanted or unexpected signal transition that occurs in a circuit before it settles to its intended value.
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A TRAP glitch is sometimes just a glitch and sometimes it's the leading edge of TRAP ringing.
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I call it a TRAP glitch by using the same rationale behind the accepted term "TRAP ringing."
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Both TRAP glitches and TRAP ringing essentially disappear when the Alternate solver is selected.
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In Glitch10 it is the massive -100A scale glitch that affects multiple signals simultaneously.
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Glitch11 shows a typical (not the glitch in Glitch10) TRAP glitch after LTspice has been zoomed in to the maximum possible.
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The waveforms in general are not germain, the glitch disturbance with femtosecond resolution is what is represented.
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All for now
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Sent:?Monday, June 02, 2025 at 12:33 AM
From:?"Andy I via groups.io" <AI.egrps+io@...> To:[email protected] Subject:?Re: [LTspice] A Huge Glitch What is a TRAP glitch?
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For that matter, what exactly is your meaning of "glitch" in this particular context?
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What are your waveforms supposed to show us?
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Unfortunately, I think no conclusions can be drawn from waveforms without knowing what they represent.
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Andy
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Re: Problem with my trying to add a potentiometer in LTSpice
¿ªÔÆÌåÓýOn 02/06/2025 19:17, Oliver Barrett via
groups.io wrote:
I looked at the symbol file within that trimpot.zip upload and discovered that the subcircuit file name must be entered into the ModelFile field, within the Attributes page of the symbol file.? I had left that blank, but fixed it this morning and my potentiometer component works correctly now.That's one way of providing the model file name. The other way is to add the directive to the schematic: .lib <modelfilename> This method has the advantages that it makes it obvious what the file name is, and second, that it provides an easy way to read the contents of that file. The disadvantage is that it has to be added to every schematic that uses it. --
Regards, Tony |
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Re: Problem with my trying to add a potentiometer in LTSpice
I looked at the symbol file within that trimpot.zip upload and discovered that the subcircuit file name must be entered into the ModelFile field, within the Attributes page of the symbol file.? I had left that blank, but fixed it this morning and my potentiometer component works correctly now.
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Thanks again for everyone's help!
Oliver |
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Re: A Huge Glitch
¿ªÔÆÌåÓýOn 02/06/2025 17:04, Dennis via
groups.io wrote:
There's no mystery. Just unread information. The official Help has always lagged. Menu > Help > Show LTspice Change log 10/8/24 LTspice 24.1.0 --
Regards, Tony |
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Re: A Huge Glitch
¿ªÔÆÌåÓýPlease always include at least a bit of the post you are replying to.? In this case, a Search for 'debugtran' cause
the Offline Manual to sulk. This is with 24.1.9. On 2025-06-02 16:04, Dennis wrote:
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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: Diode charactoristic differences between modelling tools
¿ªÔÆÌåÓýOn 02/06/2025 16:56, Andrew Lohmann via
groups.io wrote:
The two diodes I used were BAV199 at 10uA to 15mA & 1PS66SB82 at 100uA to 150uA, both running at 25'C.You could have said so. But it's clear that you entered the wrong data into the online calculators. If you hadn't, the results between those and LTspice would have be almost identical, as I showed. I can't decode what you mean about a vast difference. A difference in what? --
Regards, Tony |
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Re: Diode charactoristic differences between modelling tools
The two diodes I used were BAV199 at 10uA to 15mA & 1PS66SB82 at 100uA to 150uA, both running at 25 ¡ãC.
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This is my 1970s multimeter; the lowest ranges are 250 mV DC, 1.5V AC at 50K ohms/V and 10K ohms/V.? It does not have any electronics or a transformer, unlike an older AVO multimeter. So my question is not about small differences but a vast difference.? An |
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Re: Problem with my trying to add a potentiometer in LTSpice
All,
I just uploaded a file called Trimpot.zip.
In the past, I have had many issues with a number of pot designs in the archive.
Some designs required you to place a directive someplace on the schematic,
I thought that it would be better and easier if the part included an actual pin for the control signal.
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Tony Casey and Andy,
Since you have a such a large amount of knowledge and experience with LTspice commands.
Please feel free to modify the file "vcpot.cir" if you desire.
I suspect that one or both of you will see a superior way to control the wiper sweep.
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Comments are welcome.
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Thanks,
Mike? |
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Re: A Huge Glitch
Have you tried a run in 24.1.9 with
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.options debugtran
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This will produce diagnostic in the log file which might allow you to fix the problem.
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Best Regards,
Mathias ?
On Mon, Jun 2, 2025 at 04:49 AM, eewiz wrote:
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Re: A Huge Glitch
Hello Roy:
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The project embodied by the circuit schematic is proprietary and will be sold in commercial markets.
Therefore I am not permitted to upload the project.
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But I can say that the circuit is moderately complex, consusting of:
A's 42
B's 21 C's 105 D's 93 E's 23 F's 9 G's 16 H's 3 I's 23 L's 35 M's 7 Q's 153 R's 269 S's 21 V's 41 Which is a total of 861 elements. ?
Typical processing time for 24.0.12 is about 3400 seconds with the Alternate Solver.
The Normal Solver takes about 1800 seconds but throws more than a hundred DefCons during the simulation.
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I have no typical processing time available for 24.1.9 because it has never finished a full simulation of the project.
24.1.9 always stalls, SM aborts or TS aborts. (SM=Singular Matrix, TS=Time Step) ?
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All for now
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Sent:?Sunday, June 01, 2025 at 8:56 PM
From:?"Roy McCammon via groups.io" <roymccammon@...> To:[email protected] Subject:?Re: [LTspice] A Huge Glitch What is the circuit?
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Re: Problem with my trying to add a potentiometer in LTSpice
Hello again, I renamed the extraneous file as you requested so that it will not be used again.? Potentiometer test circuit.asc (the top level schematic) is now associated with only 2 files:? symbol file ¡°potentiometer.asy¡± and subcircuit file ¡°potentiometer.sub¡±.? When I tried running the simulation, I received this response: ? LTspice 24.1.9 for Windows Circuit: C:\Users\hoosa\Dropbox\Radio equipment_USB drive\LTSpice\Potentiometer test circuit.net Start Time: Sun Jun? 1 16:12:29 2025 C:\Users\hoosa\Dropbox\Radio equipment_USB drive\LTSpice\Potentiometer test circuit.net(4): This sub-circuit name is not defined. X¡ìX N001 0 NC_01 Rtot=10k wiper={w} ????????? ^^^^^^ ? My new upload containing these files is ¡°Potentiometer circuit-2¡±. The symbol file Attributes settings are now: Symbol type:? Cell Prefix:? X Value:? potentiometer Value 2:? Rtot=10k wiper={w} The Spice Model, SpiceLine, SpiceLine2 and ModelFile fields are blank. ? You are correct in that I don¡¯t know what I¡¯m doing, in that I still don¡¯t understand how these fhree files exchange parameter values.? In particular, I don¡¯t see where the variables Ra and Rb (as defined by the subcircuit file¡± are used.? Do I still need a separate .asc file that shows the two discrete resistors and their connection terminals? ? Yes, LTspice accesses these files from the same local hard disk and my PC that the LTspice application executes on, and Dropbox synchronizes these files with its cloud servers.? I¡¯ve not experienced any Dropbox interference issues as far as I¡¯m aware. Thanks again for your help, I hope I¡¯m getting a little closer to understanding my error. |
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Re: A Huge Glitch
¿ªÔÆÌåÓý'tera', not 'terra'. I don't see that a voltage change could be superluminal, because it's based on a field, but a current in a wire is electrons, and they can't exceed the speed of light in a vacuum, although they could exceed the sped of light in the material of the wire, while emitting Cerenkov radiation. The singular matrix must be caused by the
processing not being accurate enough, presumably making at least
one matrix element evaluate to zero instead of a finite number. On 2025-06-01 23:36, eewiz 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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A Huge Glitch
Hello All:
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I managed to catch a TRAP glitch in the wild.
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The photo Glitch10 shows a TRAP glitch that caused a singular matrix failure somewhat later at 96.518252ms.
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The photo Glitch11 shows a TRAP glitch that has been zoomed-in to femtosecond resolution.
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After following Andy's suggestion of changing the X axis to show time-96.517852ms, I was able to eventually zoom in on one of those TRAP glitches down to a fraction of a femtosecond.
As can be seen in Glitch11 in the V(v+15) pane, current changes first.
The current changes 2.88A in 157fs and probably faster because there are only two interpolated time points on the current plot.
Using the data shown, the current changes at the rate 18.3 terraamperes per second.
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The voltage changes 116 millivolts in 2.35 femtoseconds for a slew rate 50 terravolts per second.
I wonder if those changes might be superluminal and therefor impossible in this universe.
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All for now |
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Re: Installing 24.1.9 Removed My 24.0.12
¿ªÔÆÌåÓýI agree that Win32 is not a native Windows
folder, but the preference for running third-party apps is still
to put them in C:\Users\User\AppData\Local\Programs\
Why risk trouble by not doing that? On 2025-06-01 22:49, eewiz via
groups.io wrote:
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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: Installing 24.1.9 Removed My 24.0.12
Hello John:
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Yep, except my seperated versions reside in C:\Win32\LTC.
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C:\Win32 is not a native folder in Windows 10 nor windows 11.
You may be thinking of C:\Windows\System32, which is a Windows native folder, which I am not using.
C:Win32 in no more native to windows than C:\John or C:\William is.
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Windows nor LTspice has any preference where LTspice is installed.
There are places that the LTspice installer puts things because the programmer of the installer decided to put them there.
Those places are not "Preferred."
LTspice will run from wherever the Windows directory points the .asc file extension to.
Or, wherever LTspice is installed if run directly.
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You can even run multiple simultaneous copies of different versions or simultaneous copies of the same version.
The only restriction is that each copy must be cranking a differently named schematic or there will be temporary-file clash, since the .log and .raw files take on the same name as the schematic.
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All for now Sent:?Sunday, June 01, 2025 at 4:58 PM
From:?"John Woodgate via groups.io" <jmw@...> To:[email protected] Subject:?Re: [LTspice] Installing 24.1.9 Removed My 24.0.12 I'm not sure that it's good to put non-Windows files in C:/WIN32. I'm pretty sure that Windows 11 would like it here:? C:\Users\User\AppData\Local\Programs\ADI\LTspice\ltspice.exe Of course, to keep more than one version, you would need something like: C:\Users\User\AppData\Local\Programs\ADI\LTspice2x\ltspice.exe for each version. On 2025-06-01 21:48, eewiz via groups.io wrote:
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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: Installing 24.1.9 Removed My 24.0.12
¿ªÔÆÌåÓýI'm afraid I can't really comment specifically on Win11 because I've never used it. My desktop PC can run it, but my other machines can't because either their motherboard BIOS or CPU don't support Safe Boot. So, I've not considered using it. Linux is much more accommodating. But at least one of my PCs must run Widows (deliberate misspelling) because ithas ATE programs on it that aren't supported on Linux to any reasonable degree. --
Regards, Tony On 01/06/2025 23:18, John Woodgate via
groups.io wrote:
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Re: Diode charactoristic differences between modelling tools
¿ªÔÆÌåÓýThat's the distinction I was trying to make, but obviously failed. The OP mentioned "Shockley" diodes, but clearly meant "Schottky", because of the mention of low Vf.BTW, the Shockley equation works just the same with Schottky diodes, but the diode parameters are different (specifically Is), due to the lower energy gap. It even works for LEDs and UV laser diodes as well as solar panels, so long as Is is chosen appropriately. The Is default value of 1e-14 is appropriate for small BJT, but not for a diode, even though the default value is the same. These days, the equation is often not linked to Shockley, but simply called the "Ideal Diode Equation", presumably due to Shockley's fall from grace on account of his deeply unpopular predatory nature and eugenics proclivities. --
Regards, Tony On 01/06/2025 22:35, eewiz via
groups.io wrote:
Not to be confused with the Schottky metal contact diode that is not the subject of the "Shockley Diode Equation." |