How to use .param and .tran simulation in LtSpice?
Please show its use in this question-
Use SPICE to plot the output characteristic for NMOS transistors with different Length's (constant W/L). For each curve, use the waveform viewer to plot the small-signal output resistance, r0, hence verify the theoretical dependence of trans-conductance on Length that you have studied in class. Use minimum feature size of 0.18μm.
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Re: USE OF PWL FILE IN I SOURCE
What Andy said. What editor you use to generate PWL files with is the whole ball of wax, beyond just the more obvious PWL entry errors. Even the manner/format of the saved file, aside from the editor output, can mess things up. These sorts of gotcha;s have been around since the advent of personal computers. ________________________________ From: Andy <Andrew.Ingraham@...> To: LTspice@... Sent: Thursday, April 11, 2013 9:11 PM Subject: Re: [LTspice] USE OF PWL FILE IN I SOURCE ? I am trying to use a PWL file in a current (I) source however an error pops
up every time saying "Missing value for final PWL time in source I1".
I've examined my data file many times and no value seems to be missing.
Any help in explaining/resolving the error would be greatly appreciated. We can't read your mind so we can't fix the problem if you don't show us the data that causes the problem. But speaking generically ... PWL data must have an even number of values. The error message implies you have an odd number. But I assume you knew that already. Look carefully for an extra space, or some other character which might have caused a value to be split into two. If it is a very large file, does it have linefeeds? That's just another thought. [Non-text portions of this message have been removed]
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Re: USE OF PWL FILE IN I SOURCE
I am trying to use a PWL file in a current (I) source however an error pops
up every time saying "Missing value for final PWL time in source I1".
I've examined my data file many times and no value seems to be missing.
Any help in explaining/resolving the error would be greatly appreciated. We can't read your mind so we can't fix the problem if you don't show us the data that causes the problem. But speaking generically ... PWL data must have an even number of values. The error message implies you have an odd number. But I assume you knew that already. Look carefully for an extra space, or some other character which might have caused a value to be split into two. If it is a very large file, does it have linefeeds? That's just another thought.
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Re: USE OF PWL FILE IN I SOURCE
it would help a lot if you uploaded your circuit to the website. Attachments do NOT work on yahoo.
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-----Original Message-----
From: LTspice@... [mailto:LTspice@...] On Behalf Of imtiazk
Sent: Thursday, April 11, 2013 5:20 PM
To: LTspice@...
Subject: [LTspice] USE OF PWL FILE IN I SOURCE
Dear All
I am trying to use a PWL file in a current (I) source however an error pops up every time saying "Missing value for final PWL time in source I1". I've examined my data file many times and no value seems to be missing. Any help in explaining/resolving the error would be greatly appreciated.
Regards
ik
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Yahoo! Groups Links
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USE OF PWL FILE IN I SOURCE
Dear All
I am trying to use a PWL file in a current (I) source however an error pops up every time saying "Missing value for final PWL time in source I1". I've examined my data file many times and no value seems to be missing. Any help in explaining/resolving the error would be greatly appreciated.
Regards
ik
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Thank you very much aurora_iii it's all clear to me now. Another input from a friend re. using the Hierarchy to create symbols and the realisation that one can open one's own directory in the component symbol window to enable one to place the sub circuit in usual manner solves the problem. The real question is WHY ISN'T THIS PROCEDURE WRITTEN DOWN IN THE HELP FILE ? I've wasted a week trying allsorts of combinations until you answered my query. Thank you again.
Rgds
Mike Sykes
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----- Original Message -----
From: aurora_viii
To: LTspice@...
Sent: Wednesday, April 10, 2013 6:09 PM
Subject: [LTspice] Re: Sub Circuits
If it means make a subckt in a library file, this needs an ASCII text editor - I copy the net list text (menu: View > SPICE Netlist)
Paste into text editor, at the top put '.subckt [name] [nodes]'
[name] is name of your 'device', whatever; [nodes] is the node numbers or node labels of all the circuit's external connections.
At the bottom change '.backanno / .end' to '.ends'
It also needs models of any specific components (diodes, transistors etc.) as .model lines.
Text file can then be saved as, .sub .txt .lib as you prefer.
Next you need to create a symbol for it, using LTspice symbol editor. The numbering order of the symbol ports must be the same as in the subckt nodes list; '1' is first and '5' is last for .subckt name 1 2 3 4 5; or 'in+' is first and 'vout' is last for .subckt name in+ in- v+ v- vout
If as I did you look at examples it clicks into place how it all works.
HTH
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Re: Solar cell in Lt spice
--- In LTspice@..., "heitham_hh" <krouz_83@...> wrote:
--- In LTspice@..., "Helmut" <helmutsennewald@> wrote:
--- In LTspice@..., "heitham_hh" <krouz_83@> wrote:
--- In LTspice@..., "Helmut" <helmutsennewald@> wrote:
--- In LTspice@..., "heitham_hh" <krouz_83@> wrote:
hi,
how can i make a spice model for this cell?
Hello Heitham,
I have uploaded an example with your solar cell.
Files > Temp > solar_cell_4V_35mA.asc
Best regards,
Helmut
thank you Helmut for the answer,just two more question : why in I=V(VLUX)*50u you have 50u? and how did you know R2=5?
Best regards,
Heitham
Hello Heitham,
I=V(VLUX)*50u you have 50u? and how did you know R2=5? It's just a wild guess. Your datasheet contains too less
information. You may have to do a measurement on the next
sunny day to get better data. One cannot make a precise model
from nearly zero information.
Maybe you should better use 45uA and 4 Ohm.
Best regards,
Helmut
Hallo Helmut,
what you mean with same measurement to do a better model?
is it short circuit current and no-load voltage? or i need some other values?
thank you
Hello, 1. You can check with the simulation that you hit the same numbers(current, voltage) in the operating point for maximum power as in the datasheet. 2. Verify the open voltage, short current and optimum power point with a measurement. Then adjust your model. Best regard, Helmut
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Re: Solar cell in Lt spice
--- In LTspice@..., "Helmut" <helmutsennewald@...> wrote:
--- In LTspice@..., "heitham_hh" <krouz_83@> wrote:
--- In LTspice@..., "Helmut" <helmutsennewald@> wrote:
--- In LTspice@..., "heitham_hh" <krouz_83@> wrote:
hi,
how can i make a spice model for this cell?
Hello Heitham,
I have uploaded an example with your solar cell.
Files > Temp > solar_cell_4V_35mA.asc
Best regards,
Helmut
thank you Helmut for the answer,just two more question : why in I=V(VLUX)*50u you have 50u? and how did you know R2=5?
Best regards,
Heitham
Hello Heitham,
I=V(VLUX)*50u you have 50u? and how did you know R2=5? It's just a wild guess. Your datasheet contains too less
information. You may have to do a measurement on the next
sunny day to get better data. One cannot make a precise model
from nearly zero information.
Maybe you should better use 45uA and 4 Ohm.
Best regards,
Helmut
Hallo Helmut, what you mean with same measurement to do a better model? is it short circuit current and no-load voltage? or i need some other values? thank you
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Both file names still say PNP. Does someone know how to rename the AC127 file to NPN?
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--- In LTspice@..., "aurora_viii" <aurvii@...> wrote:
--- In LTspice@..., ¨¢???????? ?????????¡Á <BordodunovAlex@> wrote:
Hi.
I changed the models transistors AC127, AC128. Now the model is more correct. See the new Standard.zip file.
Bordodynov.
Excellent - this may need to be experimented with, but you're right Is is different for germaniums. I had to use 2.7e-5 to make a realistic OC35, as according to the behaviour of actual real ones.
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Ops, that didn't turn out that crisp. It all depends on the font your email program uses. You probably drew it in ASCII for a fixed font. Schematic symbols in LTspice are easily modified. LTspice includes the symbol editor. Draw it the way you like it. Change the squiggly lines to a simple rectangle. Or find someone else's. Since potentiometers are not built-in to LTspice, people add their own, and I believe several such models have been made, so you can probably find someone else's that looks the way you want yours to look. According to this group's Table of Contents file: (files > Tables of Contents > all_files.htm) there is a collection of European symbols at Andy
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.MODEL 15ljq100 D(IS=6.15446e-05 RS=0.0153982 N=1.88088 EG=1.3 ... I don't know much about the details ... but EG=1.3 might be a bit high for a Schottky diode. The LTspice help docs imply a value of 0.69 would be more typical for a Schottky. But I would be very reluctant to change any of the parameters and have something depend on the results. You could try searching the Internet for "SPICE diode model" and see what pops out. For example, this document looks interesting: Also there is the PSPICE reference manual, easily found by searching the net for "PSPCREF.pdf". Andy
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--- In LTspice@..., George <jasoto32@...> wrote:
Helmut, are there formulas or equations to change those parameters?
Sent from my iPad
Hello, You could change the parameter Eg and then rerun a temperature simulation while watching the forward voltage. You should get something like -1.5mV/¡ãC to -2mV/¡ãC. Best regards, Helmut
On 04/10/2013, at 1:02 a.m., "Helmut" <helmutsennewald@...> wrote:
--- In LTspice@..., "j_asoto" <jasoto32@> wrote:
I have to simulate a complex circuit that have zeners, magnetics, MOSFET, resistors, capacitors and different diodes. the simulation shall be performed at three different temperatures (+25C, -34C, +71C). I already have all the components model at each temperatures, but there is a model of a SCHOTTKY DIODE, that is only at +25C, which is the following:
.MODEL 15ljq100 D(IS=6.15446e-05 RS=0.0153982 N=1.88088 EG=1.3 XTI=3.60437 BV=100 IBV=0.0001 CJO=1.08848e-09 VJ=0.4 M=0.371667 FC=0.5 TT=1e-09 KF=0 AF=1)
These are the questions: In order to have the model behavior on other temperatures (-34C and +71C), which parameters from the model above I have to change? How the parameter are change?(there is a tutorial or formulas that take the temperature as a function of the parameters)?
Thanks
Hello,
The change of the forward voltage versus temperature can be set
with the parameter Eg. This allows you to adjust the -x.xmV/?¡ãC.
What also depend on temperature is leakage current in reverse
operation and series resistance Rs in forward operation.
Best regards,
Helmut
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--- In LTspice@..., ¨¢???????? ?????????¡Á <BordodunovAlex@...> wrote:
Hi.
I changed the models transistors AC127, AC128. Now the model is more correct. See the new Standard.zip file.
Bordodynov.
Excellent - this may need to be experimented with, but you're right Is is different for germaniums. I had to use 2.7e-5 to make a realistic OC35, as according to the behaviour of actual real ones.
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Re: Solar cell in Lt spice
--- In LTspice@..., "heitham_hh" <krouz_83@...> wrote:
--- In LTspice@..., "Helmut" <helmutsennewald@> wrote:
--- In LTspice@..., "heitham_hh" <krouz_83@> wrote:
hi,
how can i make a spice model for this cell?
Hello Heitham,
I have uploaded an example with your solar cell.
Files > Temp > solar_cell_4V_35mA.asc
Best regards,
Helmut
thank you Helmut for the answer,just two more question : why in I=V(VLUX)*50u you have 50u? and how did you know R2=5?
Best regards,
Heitham
Hello Heitham, I=V(VLUX)*50u you have 50u? and how did you know R2=5? It's just a wild guess. Your datasheet contains too less information. You may have to do a measurement on the next sunny day to get better data. One cannot make a precise model from nearly zero information. Maybe you should better use 45uA and 4 Ohm. Best regards, Helmut
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If it means make a subckt in a library file, this needs an ASCII text editor - I copy the net list text (menu: View > SPICE Netlist)
Paste into text editor, at the top put '.subckt [name] [nodes]'
[name] is name of your 'device', whatever; [nodes] is the node numbers or node labels of all the circuit's external connections.
At the bottom change '.backanno / .end' to '.ends'
It also needs models of any specific components (diodes, transistors etc.) as .model lines.
Text file can then be saved as, .sub .txt .lib as you prefer.
Next you need to create a symbol for it, using LTspice symbol editor. The numbering order of the symbol ports must be the same as in the subckt nodes list; '1' is first and '5' is last for .subckt name 1 2 3 4 5; or 'in+' is first and 'vout' is last for .subckt name in+ in- v+ v- vout
If as I did you look at examples it clicks into place how it all works.
HTH
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Re: The reordering of node numbers makes me crazy - is there a workaround?
To be honest I don't know the answer, but I might make a wild guess that A. it is more efficient, or safer, or something, that when a schematic is edited, to renumber unlabelled nodes as the simplest way to make sure they are all unique; B. the part that does the sim and plots is separate from the schematic editor so that it cannot possibly know beforehand, or be told even, that a node has been 'moved' to a different part of the schematic. I might also hazard a guess that it wasn't originally envisaged that anybody would edit and sim, edit and sim, edit and sim, with the plots window still open all the while, although that's what we do. I.e. by the time of the sim stage the schematic is assumed to be finished? Perhaps we're supposed to always close the plots window before changing it? Although we don't. :D
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Re: Solar cell in Lt spice
--- In LTspice@..., "Helmut" <helmutsennewald@...> wrote:
--- In LTspice@..., "heitham_hh" <krouz_83@> wrote:
hi,
how can i make a spice model for this cell?
Hello Heitham,
I have uploaded an example with your solar cell.
Files > Temp > solar_cell_4V_35mA.asc
Best regards,
Helmut
thank you Helmut for the answer,just two more question : why in I=V(VLUX)*50u you have 50u? and how did you know R2=5? Best regards, Heitham
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Ops, that didn't turn out that crisp. If you click reply you'll probably see the editing text and then what I tried to post.
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--- In LTspice@..., "per_normann@..." <per_normann@...> wrote:
There is an other symbol. It's basically the same but with a European resistor symbol instead of the Usa symbol. How would I go about changing the looks of a LTspice-component?
The symbol I look for looks something like this.
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--- In LTspice@..., "Helmut" <helmutsennewald@> wrote:
--- In LTspice@..., "per_normann@" <per_normann@> wrote:
I have a circuit that I like to present in a European
style. Most of the needed components seems to be default,
but I can't find potentiometers. Are there any European
potentiometers to be found somewhere?
Cheers!
Hello,
I only know the potentiometer symbols from our Files section.
Files > Lib > Potentiometer.
You could simply modify one of these symbol.
Best regards,
Helmut
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There is an other symbol. It's basically the same but with a European resistor symbol instead of the Usa symbol. How would I go about changing the looks of a LTspice-component?
The symbol I look for looks something like this.
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--- In LTspice@..., "Helmut" <helmutsennewald@...> wrote:
--- In LTspice@..., "per_normann@" <per_normann@> wrote:
I have a circuit that I like to present in a European
style. Most of the needed components seems to be default,
but I can't find potentiometers. Are there any European
potentiometers to be found somewhere?
Cheers!
Hello,
I only know the potentiometer symbols from our Files section.
Files > Lib > Potentiometer.
You could simply modify one of these symbol.
Best regards,
Helmut
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Helmut, are there formulas or equations to change those parameters? On 04/10/2013, at 1:02 a.m., "Helmut" <helmutsennewald@...> wrote:
--- In LTspice@..., "j_asoto" <jasoto32@...> wrote:
I have to simulate a complex circuit that have zeners, magnetics, MOSFET, resistors, capacitors and different diodes. the simulation shall be performed at three different temperatures (+25C, -34C, +71C). I already have all the components model at each temperatures, but there is a model of a SCHOTTKY DIODE, that is only at +25C, which is the following:
.MODEL 15ljq100 D(IS=6.15446e-05 RS=0.0153982 N=1.88088 EG=1.3 XTI=3.60437 BV=100 IBV=0.0001 CJO=1.08848e-09 VJ=0.4 M=0.371667 FC=0.5 TT=1e-09 KF=0 AF=1)
These are the questions: In order to have the model behavior on other temperatures (-34C and +71C), which parameters from the model above I have to change? How the parameter are change?(there is a tutorial or formulas that take the temperature as a function of the parameters)?
Thanks
Hello,
The change of the forward voltage versus temperature can be set
with the parameter Eg. This allows you to adjust the -x.xmV/¡ãC.
What also depend on temperature is leakage current in reverse
operation and series resistance Rs in forward operation.
Best regards,
Helmut
[Non-text portions of this message have been removed]
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aurvii