Re: model, subckt tube EC81 = 6R4
--- In LTspice@..., Ganesan <dg1@...> wrote:
Just make it 500 meg or something larger...
Thanx, I hope that will not be an adventuresome simulation :-) Leo
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Re: Ideal Swich Model missing
I think keep the existing terse help in LTspice... Add web links
wherever necessary and clicking the web links will give examples,
simulations and pictures, etc.. As new problems get solved they could be
added under the appropriate heading..
Just a thought..
Cheers
A. Ganesan
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On 9/17/2011 2:24 PM, Lewis wrote:
This help idea sounds great. I drafted a request to 'Panama Mike' on
this group, and copied that request to info@...
<mailto:info%40nuhorizons.com>, to copy and use scad3.pdf as a basis
for a linkable, expanded help section. Nearly all of the work
currently on the wiki can be linked to this help section, as well. If
we get permission, I'll disassemble the help file into a section on
the wiki that will serve as the stub. Hopefully others will then
amplify and illustrate this help as appropriate. I'll let the group
know when something is final on this request.
Any help link to assist others format their submissions would be
appreciated! Your submissions, analogspiceman, are outstanding by
anyone's measure... I found myself looking at your source code to see
how you did some of that stuff!
Best regards, Lewis
--- In LTspice@... <mailto:LTspice%40yahoogroups.com>,
"analogspiceman" <analogspiceman@...> wrote:
I found it much more difficult to find the specialized wiki
language help pages (most html also works at the wiki, by the
way). Perhaps I will add a direct link to the wiki help as well.
I don't think anyone needs to be a wiki language expert to start
contributing to the LTwiki as an author may just describe what the
appearance of their contribution should be and somebody else will
probably add the wiki polish if the underlying piece is compelling.
The most important thing is to write well, concise and clear.
There is a built-in editing tool set for the most common commands
(such as basic text formatting and the creation of hyperlinks),
so the mechanics of contributing soon become easy enough.
Perhaps we could set up a Help file replacement (many bits are
already in place). Many sections would likely mimic LTspice's
Help system and at least start out by heavily borrowing directly
on the existing Help, so I wonder if permission from LTC would be
required? If so, I think you be a more diplomatic choice than me
to ask Mike.
Regards -- analogspiceman
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Re: model, subckt tube EC81 = 6R4
Just make it 500 meg or something larger...
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On 9/17/2011 2:24 PM, Charly Engineering wrote:
--- In LTspice@... <mailto:LTspice%40yahoogroups.com>,
John Woodgate <jmw@...> wrote:
Are you going to operate it with grid positive to cathode? If not, you
don't need Rgk. If you are going to, you will need to find a
characteristic for grid current versus positive grid voltage, or
actually measure it. From that you can calculate Rgk.
-- No, grid will not get positive to cathode. Can I delete Rgk from the
subcircuit?
best regards Leo ...
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Re: model, subckt tube EC81 = 6R4
--- In LTspice@..., John Woodgate <jmw@...> wrote: Are you going to operate it with grid positive to cathode? If not, you
don't need Rgk. If you are going to, you will need to find a
characteristic for grid current versus positive grid voltage, or
actually measure it. From that you can calculate Rgk.
-- No, grid will not get positive to cathode. Can I delete Rgk from the subcircuit? best regards Leo ...
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Re: Ideal Swich Model missing
This help idea sounds great. I drafted a request to 'Panama Mike' on this group, and copied that request to info@..., to copy and use scad3.pdf as a basis for a linkable, expanded help section. Nearly all of the work currently on the wiki can be linked to this help section, as well. If we get permission, I'll disassemble the help file into a section on the wiki that will serve as the stub. Hopefully others will then amplify and illustrate this help as appropriate. I'll let the group know when something is final on this request.
Any help link to assist others format their submissions would be appreciated! Your submissions, analogspiceman, are outstanding by anyone's measure... I found myself looking at your source code to see how you did some of that stuff!
Best regards, Lewis
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Show quoted text
--- In LTspice@..., "analogspiceman" <analogspiceman@...> wrote: I found it much more difficult to find the specialized wiki
language help pages (most html also works at the wiki, by the
way). Perhaps I will add a direct link to the wiki help as well.
I don't think anyone needs to be a wiki language expert to start
contributing to the LTwiki as an author may just describe what the
appearance of their contribution should be and somebody else will
probably add the wiki polish if the underlying piece is compelling.
The most important thing is to write well, concise and clear.
There is a built-in editing tool set for the most common commands
(such as basic text formatting and the creation of hyperlinks),
so the mechanics of contributing soon become easy enough.
Perhaps we could set up a Help file replacement (many bits are
already in place). Many sections would likely mimic LTspice's
Help system and at least start out by heavily borrowing directly
on the existing Help, so I wonder if permission from LTC would be
required? If so, I think you be a more diplomatic choice than me
to ask Mike.
Regards -- analogspiceman
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Re: model, subckt tube EC81 = 6R4
In message <j52p27+bpi2@...>, dated Sat, 17 Sep 2011, Charly Engineering <charly020664@...> writes: I could work out mu and k for that tube-model. Unfortunately I could not get any value for Rgk of the tube. :-(
Rgk is a problem .... Are you going to operate it with grid positive to cathode? If not, you don't need Rgk. If you are going to, you will need to find a characteristic for grid current versus positive grid voltage, or actually measure it. From that you can calculate Rgk. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK When I point to a star, please look at the star, not my finger. The star will be more interesting.
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Re: wanted: opamp browsing, like transistor browsing
--- In LTspice@..., "Tony Casey" <tony@...> wrote: ... Would this do for you, or were you thinking of something else? Maybe a kind of parametric search as provided on distributors pages? Selecting a range on different parameters? I think LTspice is a program for simulation. Not for selecting parts for your hardware-schematic. Yes, it's nice that LTspice provides you the most common parameters for transistors. But choosing the appropriate parts for your hardware is another job. hws
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Re: model, subckt tube EC81 = 6R4
--- In LTspice@..., Ganesan <dg1@...> wrote:
Maybe this will help..
"Spice Models for Vacuum Tube Amplifiers" AES, March 1995
Cheers
A. Ganesan
I could work out mu and k for that tube-model. Unfortunately I could not get any value for Rgk of the tube. :-( Rgk is a problem .... best regards Leo
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Re: plotting magnetic field
--- In LTspice@..., "analogspiceman" <analogspiceman@...> wrote:
--- In LTspice@..., "samadamsspam" wrote:
I'd like to add a trace for the magnetic field for a coil to my
waveform plotting, and not sure how to do that.
I have created a parametrized "step" simulation which steps over
the inductance of a coil. I calculate a parameter for the number
of turns for the coil, which I call N.
I'd like to plot coil current * N, along with other circuit
variables.
I thought maybe a user defined function could be used, but I
don't know how to reference my variable N to pass it to the
function in the "Add Trace" dialog box.
My parameter definitions for the simulation are:
.step param Lcoil list 1m 2m 4m 6m 10m 16m
.param Rcoil = 9.8 * sqrt(Lcoil * 1000)
.param Cres = 1 / (4 * pi * pi * Lcoil * 14.5k * 14.5k)
.param C2 = 1.1 * Cres
.param C1 = 10 * C2
.param N = Rcoil * 100.0 / 24.0
.meas Rcoil_ param Rcoil
.meas Cres_ param Cres
.meas C1_ param C1
.meas C2_ param C2
.meas N_ param N
Can anyone suggest how to do this? Schematic parameters are not available to the Waveform Viewer,
but you could set up a voltage source with its value set to {N}
(be sure to include the curly braces). Label this node "N" as
well, so that the Waveform Viewer will know it as V(N), which
you may then use in waveform arithmetic. -- a.s.
Hello AS, Could not the V(nodename)@N syntax be used in the waveform viewer so that each trace of a stepped sequence can viewed unambiguously? Or have I misread the requirement? Regards, Tony
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At 7/27/2011 02:29 AM, you wrote:
How to make my own ideal diode in ltspice? Does anyone know what is the "Is Rs N Cjo M tt Iave Vpeak mfg type" value of the diode that I should put in? What I meant by ideal diode is that I get 0 current when V<0 and then a sudden peak after V>0. So the Vthreshold is exactly at 0V.
Thanks I would recommend using the level 2 switch model to create an ideal diode, as it often simulates better. You can even make the diode voltage 0. Some examples I have used: zero volt diode: .model sw_diodesw(Ron=1 Roff=1000K Vt=0 Vh=-0.05 level=2) Sdiode anode cathode anode cathode sw_diode Logic using switches: negative threshold switch .model sw_m sw(Ron=1 Roff=1000K Vt=-1.0 Vh=-0.05 level=2) positive threshold switch .model sw_p sw(Ron=1 Roff=1000K Vt=1.0 Vh=-0.05 level=2) logic inverter: Sm1 Vcc vinv 0 Vin sw_m Sp1 vinv 0 Vin 0 sw_p logic buffer: Sp2 vbuf Vcc Vin 0 sw_p Sm2 0 vbuf 0 Vin sw_m
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Re: wanted: opamp browsing, like transistor browsing
--- In LTspice@..., "carlvanwormer" <carlvanwormer@...> wrote:
The "Pick New Transistor" function is wonderful, allowing me to sort by key features for an easy selection of the available library of parts. Is there any way to access a selector menu like this for the wide selection of LT opamps? I really want to use LT opamps in my current design, but I'm getting tired of going up to the LT site and using their feature selection tool to find an appropriate opamp. If I think I need an amplifier with a faster slew rate to solve my immediate problem, it would be nice to get into the LTspice opamp selection menu, sort by slew rate, then select a device that has the proper range of features. I often find myself running simulations in places where I don't have access to the LT website, so this feature would be really nice to have. Is it already there and I just don't know about it?
Hello Carl, I'm not sure whether this would rate as equivalent to the "Pick New Transistor" dialogue, but if you open the parts chooser and browse to the Opamps sub-section, you will find pretty much all of LT's opamps there. If you step through the list, most of them have a potted description of what they are and what they do, alongside the preview of the symbol. Would this do for you, or were you thinking of something else? Regards, Tony
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Re: Ideal Swich Model missing
--- In LTspice@..., "martin562284" <martin.sadler@...> wrote:
--- In LTspice@..., "analogspiceman" <analogspiceman@> >
Well, people keeping complaining about Help, but so far no one,
including the complainers, has been willing or able to offer any
concrete constructive criticism. It remains a puzzle. -- a.s.
I posted a suggestion as to how we could collaborate on maintaining/improving the help document just a few days ago - Message no. 49532.
Hello, I think we will not have any chance to enhance the original help with tutorials. This help is intended to be a reference only. I am sure Mike will not change that. If we want a more tutorial like help, we would have to make our own with e. g. Wiki where many authors can contribute. Such a project should be preferably started from an existing tutorial to get a quicker start. Nevertheless, it will require somebody or a few to define the structure and to check the contents contributed by the many authors. Best regards, Helmut
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Re: Ideal Swich Model missing
--- In LTspice@..., "analogspiceman" <analogspiceman@...> > Well, people keeping complaining about Help, but so far no one,
including the complainers, has been willing or able to offer any
concrete constructive criticism. It remains a puzzle. -- a.s.
I posted a suggestion as to how we could collaborate on maintaining/improving the help document just a few days ago - Message no. 49532.
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Re: model, subckt tube EC81 = 6R4
--- In LTspice@..., Ganesan <dg1@...> wrote:
Maybe this will help..
"Spice Models for Vacuum Tube Amplifiers" AES, March 1995
Cheers
A. Ganesan
Thanx, yes that helps, it's possible to enter the parameters from the data-book ... best regards, Leo
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Re: Ideal Swich Model missing
--- In LTspice@..., "Lewis" <lineblp@...> wrote: LTwiki.org <> is now fixed on the front page with
a link on how to create an 'account'. This capability also exists
if one tries to 'log in'. Sorry, I did not try to make it hard,
only the anonymous spammers were taking many hours of my day to
roll back their destructive work. Hello Lewis, Some of the spammers were ferocious in their persistence, weren't they? They seemed to have had a perplexing, particular interest in the section on transformers. Never understood that. Perhaps they thought that name would attract a lot of visitors from non- techies searching for the fictitious type of "Transformer" (as in the films). Anyway, we have never really net-formally met. I believe I've seen one of your email addresses over at the LTwiki, so I will have to send you a message. By the way, I didn't have any trouble signing up - just took a very small amount of poking around to find the right page. I found it much more difficult to find the specialized wiki language help pages (most html also works at the wiki, by the way). Perhaps I will add a direct link to the wiki help as well. I don't think anyone needs to be a wiki language expert to start contributing to the LTwiki as an author may just describe what the appearance of their contribution should be and somebody else will probably add the wiki polish if the underlying piece is compelling. The most important thing is to write well, concise and clear. There is a built-in editing tool set for the most common commands (such as basic text formatting and the creation of hyperlinks), so the mechanics of contributing soon become easy enough. Perhaps we could set up a Help file replacement (many bits are already in place). Many sections would likely mimic LTspice's Help system and at least start out by heavily borrowing directly on the existing Help, so I wonder if permission from LTC would be required? If so, I think you be a more diplomatic choice than me to ask Mike. Regards -- analogspiceman
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Re: model, subckt tube EC81 = 6R4
Maybe this will help..
"Spice Models for Vacuum Tube Amplifiers" AES, March 1995
Cheers
A. Ganesan
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Show quoted text
On 9/16/2011 7:24 PM, Charly Engineering wrote:
dear friends,
I need that model for noise matching. To ask here for the model or
subckt is my last possibility.
Perhaps s.o. has ...
thanx, best regards Leo
No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 9.0.914 / Virus Database: 271.1.1/3901 - Release Date: 09/16/11 13:34:00
|
Re: Ideal Swich Model missing
LTwiki.org <> is now fixed on the front page with a link on how to create an 'account'. This capability also exists if one tries to 'log in'. Sorry, I did not try to make it hard, only the anonymous spammers were taking many hours of my day to roll back their destructive work. Create an LTwiki account <> Thanks everyone for a great online community. Lewis --- In LTspice@..., John Woodgate <jmw@...> wrote: I would be delighted to contribute to the Wiki, but its not clear
how. The front page of the Wiki says "create an account to contribute" but
there is no link or information about creating an "account". If so, it needs to be fixed.
Clearly,j genuine input is not wanted.
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Re: Ideal Swich Model missing
Hello Jim,
I agree it should be easier to find help when one needs it. In your case how to create an account on LTwiki. But then once the account is created, the instructions how to do so become irrelevant and thus clutter.
So a bit of poking around reveals that signup info is in LTwiki - toolbox - special pages - Login / signup.
As one wise old sage remarked - ...there must be a pony here somewhere! It is just up to us to find it. As frustrating as it is, I have resigned myself to this a long time ago.
Respectfuly
ME
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--- In LTspice@..., Jim Wagner <wagnerj@...> wrote:
On Sep 16, 2011, at 10:24 AM, analogspiceman wrote:
--- In LTspice@..., John Woodgate wrote:
--- In LTspice@..., analogspiceman wrote: How to make Help continue to function as a compact and efficient
reference while also being able to effectively provide answers
that neophytes can actually see, process and put to use? This is, in my experience, a problem with ALL Helps. I could write
a 3-screen post but I won't.
Well, people keeping complaining about Help, but so far no one,
including the complainers, has been willing or able to offer any
concrete constructive criticism. It remains a puzzle. -- a.s.
As far as I can see, "constructive criticism" does no good. The
documentation appears to be the sole perview of Mike and it will be
what he wants it to be.
End of story.
I have offered several positive suggestions about documentation
improvement, including the "go check PSpice documentation, its mostly
the same" and put what needs to be put into single document. That was
shot down by you and others. So, what else is one to do?
I would be delighted to contribute to the Wiki, but its not clear how.
The front page of the Wiki says "create an account to contribute" but
there is no link or information about creating an "account".
Clearly,j genuine input is not wanted.
Jim Wagner
Oregon Research Electronics
[Non-text portions of this message have been removed]
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Re: plotting magnetic field
--- In LTspice@..., "samadamsspam" wrote: I'd like to add a trace for the magnetic field for a coil to my
waveform plotting, and not sure how to do that.
I have created a parametrized "step" simulation which steps over
the inductance of a coil. I calculate a parameter for the number
of turns for the coil, which I call N.
I'd like to plot coil current * N, along with other circuit
variables.
I thought maybe a user defined function could be used, but I
don't know how to reference my variable N to pass it to the
function in the "Add Trace" dialog box.
My parameter definitions for the simulation are:
.step param Lcoil list 1m 2m 4m 6m 10m 16m
.param Rcoil = 9.8 * sqrt(Lcoil * 1000)
.param Cres = 1 / (4 * pi * pi * Lcoil * 14.5k * 14.5k)
.param C2 = 1.1 * Cres
.param C1 = 10 * C2
.param N = Rcoil * 100.0 / 24.0
.meas Rcoil_ param Rcoil
.meas Cres_ param Cres
.meas C1_ param C1
.meas C2_ param C2
.meas N_ param N
Can anyone suggest how to do this? Schematic parameters are not available to the Waveform Viewer, but you could set up a voltage source with its value set to {N} (be sure to include the curly braces). Label this node "N" as well, so that the Waveform Viewer will know it as V(N), which you may then use in waveform arithmetic. -- a.s.
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model, subckt tube EC81 = 6R4
dear friends,
I need that model for noise matching. To ask here for the model or subckt is my last possibility.
Perhaps s.o. has ...
thanx, best regards Leo
|
Leo Baumann