Re: Use a TABLE function in a BV to make a custom defined function.
On 14/03/2025 03:38, Andy I via
groups.io wrote:
I just uploaded
"LTspice_TableTest_AI.zip" to the Temp folder.? It corrects your
Bv source with the Table() function, and it shows that it works to
refer to the voltage V(SET) instead of a fixed parameter, as the
index to the table's values.
Be aware that this BV table syntax is broken in LTspice 24.1.x at
the moment. We have been assured that it will be fixed in 24.1.6,
but we don't know when that will happen.
--
Regards,
Tony
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Re: How to create IEC 61000-4-5 surge waveform in time & s behavioral ?
On 14/03/2025 07:32, ericsson.sunshine
via groups.io wrote:
Hi, :
?
May I ask a question about to generate the surge waveform
using time equation & s-equation, on how to do that in
LTspice ?
?
For example, I asked the ChatGPT, about the 6.0KV surge
waveform of time domain, then same as the s-domain equation, but
I don't quite know how to express the s-equation exactly. I
presume maybe some initial condition needed to be given, but
brain twisted. And not sure if that's supported in BV's laplace
expression, often it's for transfer function. In the following,
it shows the equation for time & s as well.
?
Then since I can't upload the file , (the policy of ... some
confidential reason, though I don't know what needed to be
confidential), I beg your pardon, please allow me to paste the
.asc content in the tail if this thread.
?
Have a nice day. Thank you very much.
Best regards.
?
the image about equation description here. (I don't know how
to insert picture correctly here, it said me don't have the
privilege.)
The solution I came up with a few years ago was to use a simple
look-up table. At the time, I needed IEC 61000-4-2. I don't know
what the differences are compared to IEC 61000-4-5, but you could
simply replace the look-up table, as necessary.
Here is a Test
Schematic.
--
Regards,
Tony
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How to create IEC 61000-4-5 surge waveform in time & s behavioral ?
Hi, :
?
May I ask a question about to generate the surge waveform using time equation & s-equation, on how to do that in LTspice ?
?
For example, I asked the ChatGPT, about the 6.0KV surge waveform of time domain, then same as the s-domain equation, but I don't quite know how to express the s-equation exactly. I presume maybe some initial condition needed to be given, but brain twisted. And not sure if that's supported in BV's laplace expression, often it's for transfer function. In the following, it shows the equation for time & s as well.
?
Then since I can't upload the file , (the policy of ... some confidential reason, though I don't know what needed to be confidential), I beg your pardon, please allow me to paste the .asc content in the tail if this thread.
?
Have a nice day. Thank you very much.
Best regards.
?
the image about equation description here. (I don't know how to insert picture correctly here, it said me don't have the privilege.)
?
Version 4
SHEET 1 1120 680
WIRE 0 112 0 96
WIRE 192 112 0 112
WIRE 672 112 672 96
WIRE 864 112 672 112
WIRE 0 208 0 192
WIRE 192 208 192 192
WIRE 672 208 672 192
WIRE 864 208 864 192
FLAG 0 208 0
FLAG 192 208 0
FLAG 0 96 V_time
FLAG 672 208 0
FLAG 864 208 0
FLAG 672 96 V_s
SYMBOL bv 0 96 R0
WINDOW 3 -274 178 Left 2
SYMATTR InstName B1
SYMATTR Value V=6000*( ?exp(-3.5e6*time) - exp(-0.14e6*time) ?)
SYMBOL res 176 96 R0
SYMATTR InstName R1
SYMATTR Value 1
SYMBOL bv 672 96 R0
WINDOW 3 -274 178 Left 2
SYMATTR InstName B2
SYMATTR Value V=1*u(time) laplace=6000*( 1/(s+3.5e6) - 1/(s+0.14e6) )
SYMBOL res 848 96 R0
SYMATTR InstName R2
SYMATTR Value 1
TEXT 148 -90 Left 2 !.tran 200u startup
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Re: Chan model for saturable transformer LTSPICE simulation
#Transformer
Hi.
The ferrite you specified is low-frequency. There is a Fe - Feddy parameter in my model. ?As the frequency increases, the magnetization reversal loop expands. See the file NonLinearTransformer_pulse_AB3.zip in the TEMP folder.
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Re: Use a TABLE function in a BV to make a custom defined function.
jad700,
?
I just uploaded "LTspice_TableTest_AI.zip" to the Temp folder.? It corrects your Bv source with the Table() function, and it shows that it works to refer to the voltage V(SET) instead of a fixed parameter, as the index to the table's values.
?
Andy
?
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Re: Use a TABLE function in a BV to make a custom defined function.
Oops, I had an extra "V=" in my reply.? Should be "V=Table" not "V=V=Table".
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Re: Use a TABLE function in a BV to make a custom defined function.
On Thu, Mar 13, 2025 at 09:50 PM, <jad700@...> wrote:
Hello? ... I need a BV source to use a TABLE to look up a response.? This works if the controlling variable is a .param ( Static for the full sim)? but I need the BV to be dynamic ( Use the TABLE lookup in response to a changing voltage and respond with the voltage result )? I have tried to do this, but no success yet.? I uploaded? LTspice_TableTest.zip to the temp folder.? Thank you so very much for any help you can provide!!? JD
The example in the schematic you uploaded does not make sense.? The syntax is wrong, and that is true even with the Table() function depending on a parameter KK.
?
The answer to your question is: what you want to do works!? Yes, the Table() function can depend on a voltage too.? The reason you had no success is that you did not use the Table() function correctly.
?
Do the following:
- Fix the Table() function.
- In your example, it is short enough so you could paste all the values into the Table() function itself.
- Verify that it works using parameter {KK}.
- Change the index parameter from "{KK}" to "V(SET)".
- Verify that it still works.
?
If you need to have the list of Table() values in an external file, you'll have to do it differently than what you tried to do.? One way to do that (prior to? LTspice V24.1.x, that is), is to write the B1 element and the .INC command as two consecutive SPICE Directive lines.? In other words, you can't use the schematic symbol for this B-source; it must be in a SPICE Directive - immediately followed by the .INC command.? Something like this:
B1 OUT 0 V=Table(V(set),
.inc table_R1.txt
which must be both in the same SPICE Directive on the schematic.? (I did not verify that this works, but I've seen others doing that.)? Also, your file table_R1.txt needs some fixing up.? Get rid of the line with the "+ n".
?
Andy
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Re: Looking for ideal fully differential amplifier spice model
The bottom ?of the E source IS the common mode input.
?
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Use a TABLE function in a BV to make a custom defined function.
Hello? ... I need a BV source to use a TABLE to look up a response.? This works if the controlling variable is a .param ( Static for the full sim)? but I need the BV to be dynamic ( Use the TABLE lookup in response to a changing voltage and respond with the voltage result )? I have tried to do this, but no success yet.? I uploaded? LTspice_TableTest.zip to the temp folder.? Thank you so very much for any help you can provide!!? JD
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Re: Chan model for saturable transformer LTSPICE simulation
#Transformer
Hi, Thanks for the reply. Thank you for correcting my core. I would like to know what do you mean by/ how did you say that my core is small. Which parameters determine the core? If I have to work with a core that has high squareness ratio(=0.96 in this example) and with high voltage high frequency, I only found out that Finemet FT-3SH core is better suitable. However, the B values can be adjusted using the annealing process. I chose the same A, lm values, how to choose H here?
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On Thu, Mar 13, 2025 at 06:04 AM, John Waugaman wrote: The original LM321 (as well as the LM121 and LM221) is described as a
"Precision Preamplifier" in the 1976 to 1982 linear data books, Hello to all, I have looked into my NSC documents and in this threat about LM121/LM221/LM321: 1972 (none) 1976 LM121/LM221/LM321 Precision Amplifier 1980 LM121/LM221/LM321 Precision Amplifier 1988 LM221/LM321 Precision Amplifier 1995 LM221/LM321 Precision Amplifier 1999 (none) 2001 LM321 Single Op Amp The "Precision Amplifier" documentation was published for about 20 years. Between 1980 and 1988 the LM121 version (-55...125 ¡ãC) was discontinued. In April 2001 the Single Op Amp appeared. But a few years earlier LMV321 and LPV321 (single versions of LMV324 resp. LPV324) were published. In 2011 National Semiconductor became part of Texas Instruments. In addition I have just uploaded a 1995 version of NSC AN-79 "IC Preamplifier Challenges Choppers on Drift" - LM121, 1973-02 graphical update 1995. I did not find any difference to the former versions but the quality is a bit better e.g. the LM121 chip foto and scalable text (no pixel scan) Bernhard
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Re: Schematic shows different sized text
On Thu, Mar 13, 2025 at 04:14 PM, <charles@...> wrote:
My file is AC_Coupling.asc ...
Ah.? That was your way of telling us that you uploaded that file.? In the future, please make it a little more obvious, so that even slow people like me notice it.
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Indeed, it looks like it was?saved more than a decade ago, before Mike Engelhardt changed LTspice's "default" font size.? The result is that some of the text now looks tiny - and some doesn't.
?
I ran it through LTspice with the 'FixUpSchematicFonts command-line switch, and saved it as "AC Coupling FixedFonts.asc" in the "Temp" folder.
?
Andy
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Re: Schematic shows different sized text
On Thu, Mar 13, 2025 at 04:14 PM, <charles@...> wrote:
My file is AC_Coupling.asc and has text that has been made smaller than it was in older LTSpice versions. The weird part is some text is small but other text is normal. Using version 24.0.12.
Is there a question in there?
?
Most text on LTspice schematics can be changed to different sizes.
?
There is the global setting, in the Control Panel (Settings) > Drafting Options > Font Properties > Size.? That setting would affect the difference between text, and symbols and wires.? In my opinion, it is best left alone, or else you may end up with schematics that are unreadable when viewed by other LTspice users.
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And then there is the relative text size setting, for some but not all types of text.? You can change the relative size of comment text, as well as text that is attached to symbols, but not Labels (net names).? Right-click on the text and look for "Font Size".? The choices probably are 0.625, 1.0, 1.5(default), 2.0, 2.5, 3.5, 5.0, and 7.0.? These can be used to scale individual texts up or down in size.
?
If you created schematics in VERY old versions of LTspice (probably LTspice III which was MANY years ago), then the text might have been saved differently in the .asc file, causing their text to look tiny when the schematic is opened in newer versions (LTspice IV, LTspice XVII, or LTspice 24).? LTspice has two command-line switches (-FixUpSymbolFonts and -FixUpSchematicFonts) to "repair" those old schematics or symbols that had that problem.? See the Help page for Modes of Operation > Command Line Switches.
Andy
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Re: Schematic shows different sized text
Yes, this is known about, and it's a nuisance.
There is a file that fixes it, but it has to be run from the
command line. Instead, you can click on each small text (use the
magnifier (plus sign on the toolbar) if necessary and rest the
size to 1.5, which is the default.
My file is AC_Coupling.asc and has text that has been made
smaller than it was in older LTSpice versions. The weird part is
some text is small but other text is normal. Using version
24.0.12.
--
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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Schematic shows different sized text
My file is AC_Coupling.asc and has text that has been made smaller than it was in older LTSpice versions. The weird part is some text is small but other text is normal. Using version 24.0.12.
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Re: Schematic drawing issues
Just reporting that in 24.1.5, and using my 65 inch 4k screen....
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When adding a wire, I can very faintly see the extended crosshairs and cursor.
So faintly are the crosshairs that LTspice 24.1.5 is unusable with my 65 inch screen.
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I can see the cursor as long as I don't add a wire.
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Typo alert.??I wrote:
...? It's about a million times easier than combing through 20 years of scattered models, ...
Andy
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Re: Issue with Nexperia BUK7S1R0-40H PET LTspice model
I just uploaded "BUK7S1R0-40H with 2019 model.zip" to the Temp folder.
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Andy
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Re: Issue with Nexperia BUK7S1R0-40H PET LTspice model
Since the model is a .SUBCKT with 3 pins, and the symbol has 3 pins, I conclude that the most likely cause of the problem is user-error (cockpit error).? You did something wrong.? Try again.
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Andy
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FYI, by looking at a diode model, you can't tell how it performs.? You would need to do several simulations of each and every diode model, to extract the data you are looking for.
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Much, MUCH easier to just look at the table that is already built into LTspice itself.
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Andy
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Tony Casey
John Woodgate