Re: Problem with my trying to add a potentiometer in LTSpice
On Sat, May 31, 2025 at 06:32 PM, John Woodgate wrote:
I think it would be good and logical to allow a click on the symbol terminal to plot the voltage there.
LTspice has never allowed that.
?
You can click on a wire as a short-cut way to plot its voltage.? Or you can click on a pin as the short-cut to plot its current (the current into the pin).? But clicking on a pin never works to plot a voltage, and I would argue that it should not.
?
There isn't really any way to guess that the steps that you explain will make it work.
Ah, but there is.? The plot window shows the names of the things being plotted, at the top of the pane.? There are other ways to get those names up there, besides only point-and-click with a mouse on your schematic.? Among them are:
- Plot Settings > Add Trace
- Plot Settings > Visible Traces (once the plot window is already displayed)
- Alt-P-V
- Right-click > Add Traces
- Right-click > View > Visible Traces (once the plot window is there)
- Ctrl-A
- Right-click on any name at the top of the plot and change it to something else
Any way that you have to enter a node voltage, or a pin current, and make it appear at the top of a plot pane, works.? Most of the choices listed above come with a selection menu from which you can choose what signal you want to plot.? I told you which signal name you needed to plot in this case, which I discovered by hovering the mouse pointer over the pin.? That is always how it works in LTspice.? LTspice can't read your mind, so you need to use actions like clicking, or hovering over something.
?
We often talk about doing things like editing the name at the top of the waveform plots.? It might not be immediately obvious to the very first-time user, but neither is it obvious that clicking on a wire could plot its voltage.? Everything comes with experience, plus reading the Help for guidance.
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Re: Problem with my trying to add a potentiometer in LTSpice
I think it would be good and logical to allow
a click on the symbol terminal to plot the voltage there. There
isn't really any way to guess that the steps that you explain
will make it work.
On 2025-05-31 23:19, Andy I via
groups.io wrote:
On Sat, May 31, 2025 at 06:11 PM, John Woodgate wrote:
Well, when I try it,
LTspice will not plot the voltage on pin 2.
That's right, if you try to point to a net to plot its
voltage.? Because there is no net (node) to point to, you can't
just click on the net to plot its voltage.
?
But that is not the end of the story.? The net (or node)
exists, under the name "NC_01".? You can plot
it if you go to the Add Traces menu and find that net.? Look for
"V(nc_01)" and select it and click OK.
?
And, because it is just a pin but not a net, you can plot the
current into the pin by clicking on it.? The current is, of
course, 0.
?
It's the lack of a wire
that causes that. When I add a wire, it works.
You are right.? But the simulation works with or without the
wire.? It's just that you can't click on the wire when there is
no wire to click on.? That's all.
?
Andy
?
--
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: Problem with my trying to add a potentiometer in LTSpice
On Sat, May 31, 2025 at 06:11 PM, John Woodgate wrote:
Well, when I try it, LTspice will not plot the voltage on pin 2.
That's right, if you try to point to a net to plot its voltage.? Because there is no net (node) to point to, you can't just click on the net to plot its voltage.
?
But that is not the end of the story.? The net (or node) exists, under the name "NC_01".? You can plot it if you go to the Add Traces menu and find that net.? Look for "V(nc_01)" and select it and click OK.
?
And, because it is just a pin but not a net, you can plot the current into the pin by clicking on it.? The current is, of course, 0.
?
It's the lack of a wire that causes that. When I add a wire, it works.
You are right.? But the simulation works with or without the wire.? It's just that you can't click on the wire when there is no wire to click on.? That's all.
?
Andy
?
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Re: Problem with my trying to add a potentiometer in LTSpice
Well, when I try it, LTspice will not plot the
voltage on pin 2. That's what I meant.? It's the lack of a wire
that causes that. When I add a wire, it works.
On 2025-05-31 22:58, Andy I via
groups.io wrote:
On Sat, May 31, 2025 at 05:50 PM, John Woodgate wrote:
... However, the way you
have made your symbol and potentiometer.asc doesn't work.
LTspice can't understand pin 2.
I disagree.? Pin 2 of the potentiometer just has nothing
connected to it, so it is "floating" externally to the pot.?
That does not make it a floating net, however, because it has
the resistive path to ground, so it's OK, SPICE-wise.
?
In the netlist, it just lacks a wire and a "proper" netname,
so LTspice assigns it a netname of "NC_01" where the "NC"
suggests "Not Connected", as in nothing else is connected to
it.? Drawing even just a wire to that pin would change it from
"NC_01" to "N002" which really is just a change of names.
?
Regardless, LTspice understands it just fine and the
simulation works.
?
?
--
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: Problem with my trying to add a potentiometer in LTSpice
Sorry, this came out wrong.? I wrote:
FYI, I noticed that you defined values for parameters R and Val that you passed to the potentiometer.
What I meant to say is that you defined those values twice.? It should be done only once.? One of the two should be deleted.
?
Andy
?
?
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Re: Problem with my trying to add a potentiometer in LTSpice
On Sat, May 31, 2025 at 05:50 PM, John Woodgate wrote:
... However, the way you have made your symbol and potentiometer.asc doesn't work. LTspice can't understand pin 2.
I disagree.? Pin 2 of the potentiometer just has nothing connected to it, so it is "floating" externally to the pot.? That does not make it a floating net, however, because it has the resistive path to ground, so it's OK, SPICE-wise.
?
In the netlist, it just lacks a wire and a "proper" netname, so LTspice assigns it a netname of "NC_01" where the "NC" suggests "Not Connected", as in nothing else is connected to it.? Drawing even just a wire to that pin would change it from "NC_01" to "N002" which really is just a change of names.
?
Regardless, LTspice understands it just fine and the simulation works.
?
?
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Re: Problem with my trying to add a potentiometer in LTSpice
On Sat, May 31, 2025 at 05:30 PM, Oliver Barrett wrote:
Hello,
I'm having trouble adding a potentiometer component in LTSpice, and I've uploaded a zip file to the Files area of this group (Potentiometer circuit.zip) to show my data.? The simulation does not recognize my .param statements.
?
Included in the zip file are three files:
Potentiometer.asc (contains the separate resistors and the .param statements)
Potentiometer.asy (contains the custom symbol)
Potentiometer test circuit.asc (contains the separate resistors, the .param statements and the custom symbol
?
Do the circuit elements and my parameter settings look correct in the screenshot (included in the zip file)?
Apparently, the circuit you uploaded is not the same one you tried to simulate.
?
I ran the simulation of the circuit you uploaded, and it worked perfectly - after I added the missing simulation command.? That is a clear sign that you never simulated the circuit that you uploaded.? A second clue of that, is the fact that the image you uploaded does not look like the schematic you uploaded
?
Please download and unzip the .ZIP file you uploaded, and try it again.
?
FYI, I noticed that you defined values for parameters R and Val twice, that you passed to the potentiometer.? It is not necessary to do that twice, but it is a good idea to make both of them visible on the schematic.? Notice the missing "X" in the "Vis." column for the Value attribute (after Ctrl-right-click on the potentiometer symbol).??Again, this does not look like the image you uploaded.? Please get your files straight first, then try simulating it again.
?
Are you seriously simulating from within a Dropbox drive?? That is not a good idea.
?
Andy
?
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Re: Problem with my trying to add a potentiometer in LTSpice
Your .ASC doesn't have a simulation directive,
but .TRAN 1m would do. However, the way you have made your
symbol and potentiometer.asc doesn't work. LTspice can't
understand pin 2. But you could have saved a lot of effort by
searching the list archives, the 'z_xxx' folders within Files.
There are several examples of potentiometers already that work.
It's a bit of a pity that we haven't persuaded ADI to include
one in LTspice native components yet.
The JPG is no help, and should have been
uploaded to Photos, not Temp.
On 2025-05-31 22:23, Oliver Barrett via
groups.io wrote:
Hello,
I'm having trouble adding a potentiometer component in
LTSpice, and I've uploaded a zip file to the Files area of this
group (Potentiometer circuit.zip) to show my data.? The
simulation does not recognize my .param statements.
?
Included in the zip file are three files:
Potentiometer.asc (contains the separate resistors and the
.param statements)
Potentiometer.asy (contains the custom symbol)
Potentiometer test circuit.asc (contains the separate
resistors, the .param statements and the custom symbol
?
Do the circuit elements and my parameter settings look
correct in the screenshot (included in the zip file)?
?
Thank you for your help.
--
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
|
Problem with my trying to add a potentiometer in LTSpice
Hello,
I'm having trouble adding a potentiometer component in LTSpice, and I've uploaded a zip file to the Files area of this group (Potentiometer circuit.zip) to show my data.? The simulation does not recognize my .param statements.
?
Included in the zip file are three files:
Potentiometer.asc (contains the separate resistors and the .param statements)
Potentiometer.asy (contains the custom symbol)
Potentiometer test circuit.asc (contains the separate resistors, the .param statements and the custom symbol
?
Do the circuit elements and my parameter settings look correct in the screenshot (included in the zip file)?
?
Thank you for your help.
|
Re: AD8476 model in ltspice
A SPICE macro model is available from Analog Devices.
On Fri, May 30, 2025, 5:22?PM Tony Casey via <antoniustrevorum= [email protected]> wrote:
On 30/05/2025 23:09, john23 via
wrote:
Hello,I want to build a single ended to differential
converter described in the circuit bellow.
There is no ltspice model for AD8476 in the program? library.
Is there some alternastive source for the spice model?
I guess you didn't check the ADI website on the AD8476 product page:
--
Regards,
Tony
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Re: AD8476 model in ltspice
On 30/05/2025 23:09, john23 via
groups.io wrote:
Hello,I want to build a single ended to differential
converter described in the circuit bellow.
There is no ltspice model for AD8476 in the program? library.
Is there some alternastive source for the spice model?
I guess you didn't check the ADI website on the AD8476 product page:
--
Regards,
Tony
|
?
Hello,I want to build a single ended to differential converter described in the circuit bellow.
There is no ltspice model for AD8476 in the program? library.
Is there some alternastive source for the spice model?
Thanks.
?
https://www.analog.com/en/resources/analog-dialogue/articles/versatile-precision-single-ended-to-differential-converter.html
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Re: Flip Flop and NAND gate
Another thing you can try is Google Books ngram viewer.
This shows you what made it to publication (and when).? Best regards,? Spehro Pefhany?
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Show quoted text
On May 29, 2025, at 5:49?PM, eewiz via groups.io <eewiz@...> wrote:
? Hi Andy,
?
After searching for something on Google, look upper-right and click the down arrow next to the tools word.
?
All for now
?
?
Sent:?Thursday, May 29, 2025 at 4:27 PM
From:?"Andy I via groups.io" <AI.egrps+io@...>
To:[email protected]
Subject:?Re: [LTspice] Flip Flop and NAND gate
eewiz wrote:
Colleges with textbooks may teach that it is an "SR latch" but people in general prefer the term "RS latch."
Even agrees with "SR latch".
?
Wikipedia is not the authority.? But I would judge it more dependable than Google searches.
?
I have forgotten how to get counts of 'hits' from Google searches.
?
Andy
?
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Re: Using exported gate signals from PLECS
Thank you very much.
On 2025-05-30 07:41, Mathias Born via
groups.io wrote:
In the documentation of the independent voltage source, where
the PWL parameter is explained. "SCOPEDATA"
in the search box will find it.
?
Of
course, I'm referring to the latest LTspice version, which is
what the vast majority of users use.
?
Best
Regards,
Mathias
?
On Fri, May 30, 2025 at 12:24 AM, John Woodgate wrote:
Can you please say where
it is in the Help? I cannot find it, and 'Find keyword'
doesn't work.
On 2025-05-29 22:44, Mathias Born
via groups.io wrote:
SCOPEDATA=...
was introduced precisely for what the OP is trying to do. It
provides the legacy behavior. PWL=... will only work for
data with montonically increasing x-values. All documented
in great detail in the help.
--
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
|
Re: Using exported gate signals from PLECS
On 30/05/2025 08:41, Mathias Born via
groups.io wrote:
Of course, I'm
referring to the latest LTspice version, which is what the vast
majority of users use.
I wouldn't be too sure about that. Unless, of course LTspice has a
little "phone home" routine that reports usage, like Microsoft . In
any event, those don't work for computers not connected.
Many people stick with whatever version they first installed. I
don't have the latest version. That would require updating every few
days, recently.
--
Regards,
Tony
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Re: Using exported gate signals from PLECS
In the documentation of the independent voltage source, where the PWL parameter is explained. "SCOPEDATA" in the search box will find it.
?
Of course, I'm referring to the latest LTspice version, which is what the vast majority of users use.
?
Best Regards,
Mathias
?
On Fri, May 30, 2025 at 12:24 AM, John Woodgate wrote:
Can you please say where it is in the Help? I cannot find it, and 'Find keyword' doesn't work.
On 2025-05-29 22:44, Mathias Born via groups.io wrote:
SCOPEDATA=... was introduced precisely for what the OP is trying to do. It provides the legacy behavior. PWL=... will only work for data with montonically increasing x-values. All documented in great detail in the help.
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Re: Flip Flop and NAND gate
Andy,? Do you know where I can find an integrated circuit model that functions as a JK flip-flop, such as the CD4027?
I’ve searched through several suppliers and websites, but I couldn’t find a SPICE model.
I need to use a JK flip-flop in my inverter to introduce a delay between the switching of transistors and allow my RL load enough time to discharge properly.
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On 29 May 2025, at 16:24, Andy I via groups.io <AI.egrps+io@...> wrote:
? On Thu, May 29, 2025 at 10:58 AM, Guilherme Souza wrote:
I had the idea of building a JK flip-flop circuit (after finishing the RS) using digital gates in LTspice, and then using it to control the PWM of my inverter circuit.
This should not influence you....? But I never understood the purpose of JK flip-flops.? Logically speaking, they are just a little weird.? Maybe there is a place for them but I never understood it.
?
Mind you, a JK flip-flop was the first one I experimented with.? But in the years since, I think I never encountered a circuit that used them.
?
I'll leave the flip-flop construction for another software like LogiSim.
That is not a bad idea, when all you want to know is what are their logic states.? Actual circuits with actual voltages can be a bigger challenge, and simulating them has its own challenges too.? Those are worth knowing too, but not necessary to understand the basics of binary logic.
?
Andy
?
?
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Re: Using exported gate signals from PLECS
I read Pedro’s comment, and figured he *probably* misunderstood “Time must be monotonically increasing”, which I believe is the case, not Value.
?
Dave
?
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From: [email protected] <[email protected]>
On Behalf Of Andy I via groups.io
Sent: Thursday, May 29, 2025 1:37 PM
To: [email protected]
Subject: EXTERNAL: Re: [LTspice] Using exported gate signals from PLECS
?
The "PWL file" is only for monotonically increasing sources. Since mine is another simulation's export that does not happen. That's why I am using this SCOPEDATA definition.
I'm afraid that is incorrect.
PWL, either with or without "PWL file=", is not only for monotonically increasing sources.? Were you taught that?? ?That would be incorrect.? It is for any kind of point-by-point
(piecewise linear in time) signal description.
(And be aware of the difference between a PWL I/V curve, and a PWL V/time description.? The PL in PLECS stands for Piecewise Linear, which I believe refers to its use of piecewise linear electrical descriptions of a device's nonlinear I/V
characteristics at any instant in time.? That is not the same thing as a SPICE source that is piecewise-linear in time.)
SPICE/LTspice does not have the name "SCOPEDATA".? Maybe it came from a scope or from another simulation (MATLAB?), but if it is a piecewise-linear voltage/time table, then that is what it is.? You need to call it a "PWL file" to use it
in LTspice.? Don't use the term "SCCOPEDATA" in LTspice.
By the way, I point out again that LTspice is spelled "LTspice", not "LTSpice".
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Re: Using exported gate signals from PLECS
Can you please say where it is in the Help? I
cannot find it, and 'Find keyword' doesn't work.
On 2025-05-29 22:44, Mathias Born via
groups.io wrote:
SCOPEDATA=... was
introduced precisely for what the OP is trying to do. It provides
the legacy behavior. PWL=... will only work for data with
montonically increasing x-values. All documented in great detail
in the help.
--
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
|
Re: Flip Flop and NAND gate
On 29/05/2025 16:58, Guilherme Souza
via groups.io wrote:
Thank you for the feedback.
I will study more about all the points that were raised.
I had the idea of building a JK flip-flop circuit (after
finishing the RS) using digital gates in LTspice, and then using
it to control the PWM of my inverter circuit.
But I believe a less labor-intensive path would be to import a
model of an integrated circuit into LTspice.
I'll leave the flip-flop construction for another software like
LogiSim.
If you're wanting to use use digital blocks for a real application,
you should note that there are libraries in the LTspice group Files section for
CD4000, 74HC, 74HCT and 74LVC series gates that are based on the
real world devices.
--
Regards,
Tony
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John Woodgate
Tony Casey
Bell, Dave