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Tube life is related more to the temperature of their envelope, if the heater is reliably constructed.



I'm not sure that you can assume a more reliable tube technology, post 1960. A fifty year old piece of equipment has not demonstrated a 50 year component life.......

RL

Hi folks,

my LTspice-version has problems with that circuit :-)

help!

best regards Leo ...

<snip>

Hi Tony and others,
Three more questions:
1) If prefix for an nmos.asy symbol is stated as MN, what does that mean?
2) Could you also try to explain what an intrinsic model is, I don't think I exactly understand that?
3) Is it possible to place a model elsewhere than under the &#92;lib&#92;sub folder or schematic folder besides from an website?

Regards
Carsten

</snip>
Hello Carsten,

1. The MN prefix tells SPICE that the device is an N-channel MOSFET.
2. An intrinsic device is a fancy name for a circuit element that is built in to the SPICE code. Please read the LTspice>Circuit Elements section of the Help for a complete list.
3. It is frequently recommended to avoid placing any user files in any part of installation tree, particularly if you expect to have to share simulation files with co-workers etc (it may also be overwritten in an update if Mike introduces a file of the same name - unlikely, but possible). This is because you cannot everyone else will have the same files there; you should only assume they will have the installation defaults. The advice is therefore to place any user files (.models, subcircuits, .meas scripts) in the folder containing the top level schematic. LTspice will always find them there. In principle, you can place a model anywhere if you provide an absolute path to the file in the .inc statement, but it's asking for trouble. Nevertheless, people continue to ignore the advice.

Regards,
Tony

--- In LTspice@..., Tan Micheline Tambayong <micheline.tambayong@...> wrote:

Hi Helmut,
Thanks for the reply. I already uploaded the file under name
Pefficiency_analysis.asc.
Please try to simulate the power in V1 and power in R1 since I am analyzing
the Power efficiency (Pout/Pin) of the circuit. Also if you try to simulate
using C = 16uF it's simulating just fine but it gives error when you try C =
17uF... You can try other value of C as well. It gives error for only some
values of C above 16uF.
Hope you can find out why it behaves as such..
Thanks so much for the help

Kind regards,
Micheline


On Mon, Sep 19, 2011 at 4:32 PM, Helmut <helmutsennewald@...> wrote:

**




--- In LTspice@..., Tan Micheline Tambayong
<micheline.tambayong@> wrote:

Does anyone know what its means when LTspice give error:
"Singular matrix: check node n002
Iteration No. 1"

The circuit is made by AC voltage source, resistor (series with the

voltage

source), bridge rectifier, capacitor, resistor paralleled with the

capacitor

as a load at the output, and ground. The circuit is plotting and

simulating

just fine for small value of capacitor. But when I increase the capacitor
value above 16uF, LTspice give the above error. But for some capacitor
values (eg. 20uF) it's fine again, and when I increase it again

(eg.21uF),

it gives error again. So LTspice gives error for most of capacitor value
above 16uF but not all.. Also, for some value, it simulating but then the
plot stops in the middle. The value of the capacitor that gives an ok

plot

and error are randoms (no pattern). So does anyone know, what's the

reason

that the LTspice behaves like this?

Thanks in advance..

Kind regards,
Micheline

Hello Micheline,

This error message simply means that LTspice couldn't solve
the matrix. Maybe your circuit has an open nets.

Please upload your circuit to this group for a test to the
following location.

Files > Temp > yourcircuit.asc



Best regards,
Helmut

Hello Micheline,

Your circuit won't converge because of the ideal diode model. If you add Roff=10Meg to the model, it fixes the convergence issue.

Regards,
Tony

--- In LTspice@..., "Tony Casey" <tony@...> wrote:

--- In LTspice@..., "pindsen" <windven@> wrote:

--- In LTspice@..., "Helmut" <helmutsennewald@> wrote:

--- In LTspice@..., "pindsen" <windven@> wrote:

Hi,

I need an BSS138 in my LTSpice simulation.
Since I can't find that component in the program itself, I need to make it.

I have done the following steps but LTspice won't simulate:

1) Downloaded a Zetex BSS138 spice subcircuit and placed it in a "BSS138.sub" file
2) The spice file is placed in c:&#92;program files&#92;LTC&#92;LTspiceIV&#92;lib&#92;sub
3) Included a nmos symbol (nmos.asy) in the design
4) Renamed the symbol to BSS138/ZTX
5) Add a spice directive command ".inc BSS138.sub"
6) Hit the run button
7) LTspice can't simulate and says "Can't find definition of model "bss138".

The Zetex spice model can be seen here:

*ZETEX BSS138 Spice Mosfet Subcircuit Last revision 11/91
*
.SUBCKT BSS138/ZTX 3 4 5
* Nodes D G S
M1 3 2 5 5 MOD1
RG 4 2 343
RL 3 5 6E6
D1 5 3 DIODE1
.MODEL MOD1 NMOS VTO=1.109 RS=1.474 RD=1.59 IS=1E-15 KP=0.597
+CGSO=23.5P CGDO=4.5P CBD=53.5P PB=1 LAMBDA=267E-6
.MODEL DIODE1 D IS=1.254E-13 N=1.0207 RS=0.222
.ENDS

Can anyone help?

Best regards
Carsten Wind
Denmark

Hello Carsten,

4a)
Ctrl-right-mouse-click on the placed symbol nmos.
Change Prefix:MN to Prefix:X

2) I always recommend to save model files in the folder of the
schematic.

Best regards,
Helmut

Hello Helmut,
Thanx for your answer.
I did what you proposed in 4a) and it worked :-) But what does it do? What is Prefix and what does a change from MN to X do?

Then, how should the .include statement look like if the model files is placed in the folder of the schematic?

Best regards
Carsten Wind

Hello Carsten,

The X prefix tells the SPICE netlister that the device is represented by a subcircuit, and not an intrinsic model.

If the subcircuit is placed in the same directory as the schematic, then the include line is simply:
.inc subcircuitfilename.ext

Regards,
Tony

Hi Tony and others,
Three more questions:
1) If prefix for an nmos.asy symbol is stated as MN, what does that mean?
2) Could you also try to explain what an intrinsic model is, I don't think I exactly understand that?
3) Is it possible to place a model elsewhere than under the &#92;lib&#92;sub folder or schematic folder besides from an website?

Regards
Carsten

--- In LTspice@..., "Heinz-W. Schockenbaum" <schockenbaum@...> wrote:

Which german newsgrop?

de.sci.electronics, You can have plenty of knowledge, first You will get canings :-)

best regards Leo ...

--- In LTspice@..., "Randoid" <randoid@...> wrote:

Has Mike Engelhardt ever expressed interest in taking a poll of us users on this forum for improvements that we would like to see? Seems like a natural fit to me.

There is something I would like different, but have always been so grateful for LTspice that I didn't want to rock the boat;

In the schematic editor, it is not possible to pan far (or sometimes at all) past the extent of the existing schematic.

For example, imagine that I have the output of a circuit and want to add some load to it. Often I end up zooming right out so I can see to the right and then place a GND somewhere over there so I can zoom in again and place my new bits.

If you copy a block of circuit, it gets even worse as you try to pan past the existing circuit, and LTspice says "oh no you don't!" and bounces back. Sometimes I place a few GND points around and then have to move the entire schematic over a bit to make space on one side to extend it.

I also like analoguespiceman's suggestion, and would like to have this feature added to a number of other applications that I use :)

A collegue suggested that I put the parasitics of the kapacitor in discrete components in series, and that fixed the problem. Bug?

/Johan

Hiya Mike

Now that I have well over 100 different diode types in Ltspice I think that something that I would find useful would be a selector box for diode type "All, Germanium, Silicon, ZENER, SCHOTTKY, VARACTOR, LED" above the select window.

A filter search where you could type in the first couple of characters of the diode ID for instance 1N or BZY which then only displays those models that match the filter.

Regarding Ltspice recognised added parameters Vpk, Ipk, Iave, Irms and diss it would be nice to add 'Cv4' which gave the capacitance of a Varactor when negatively biased at -4 volts

Thus when the select box has 'Varactor' selected it would display the Vpk and Cv4 of the device. When the others are selected the display should be as it is now.


The text editor.

I have spent some time using the test editor, and have found that it does have a quirk, that is that it switches from insert mode to overtype when text is pasted into the file being edited.

Adding mouse select and move would be nice too.


Overall


It's a damn fine program, and wouldn’t dream of using any other for spice. Keep up the excellent work. Thank you


Best regards

Suusi Malcolm-Brown

--- In LTspice@..., Michael Peter Kiwanuka <michael883575@...> wrote:

Could you please post the circuit schematics, Symbols, and models and all relevant files in the Temp files of this group ? It is a lot easier with a schematic to troubleshoot.

Schematic is uploaded, but the calculation is missing.
Temporary P(in) is zero (as capacitor is already loaded and I(in) is zero.)

That may cause a division by zero.

hws

--- In LTspice@..., Tan Micheline Tambayong <micheline.tambayong@...> wrote:

I already uploaded the file under name Pefficiency_analysis.asc.

Methode how to calculate efficiency is missing.

Please notice that R1 is not connected to gnd. I suppose you calculated like this: voltage should be: V(n003)-V(n004). Current is I(R1) so power is (V(n003)-V(n004))*I(R1)
Divide Output power by input power?...

Your uploaded simulation works for me.

hws

Hi Micheline,

Could you please post the circuit schematics, Symbols, and models and all relevant files in the Temp files of this group ? It is a lot easier with a schematic to troubleshoot.

Best regards,

Michael




To: LTspice@...
From: micheline.tambayong@...
Date: Mon, 19 Sep 2011 15:21:03 +1000
Subject: [LTspice] SPICE Error






Does anyone know what its means when LTspice give error:
"Singular matrix: check node n002
Iteration No. 1"

The circuit is made by AC voltage source, resistor (series with the voltage
source), bridge rectifier, capacitor, resistor paralleled with the capacitor
as a load at the output, and ground. The circuit is plotting and simulating
just fine for small value of capacitor. But when I increase the capacitor
value above 16uF, LTspice give the above error. But for some capacitor
values (eg. 20uF) it's fine again, and when I increase it again (eg.21uF),
it gives error again. So LTspice gives error for most of capacitor value
above 16uF but not all.. Also, for some value, it simulating but then the
plot stops in the middle. The value of the capacitor that gives an ok plot
and error are randoms (no pattern). So does anyone know, what's the reason
that the LTspice behaves like this?

Thanks in advance..

Kind regards,
Micheline

[Non-text portions of this message have been removed]






[Non-text portions of this message have been removed]

--- In LTspice@..., "Charly Engineering" <charly020664@...> wrote:

very kindly people here by
...
much more than in our german newsgroups :-)

Which german newsgrop?

hws

Hi Helmut,
Thanks for the reply. I already uploaded the file under name
Pefficiency_analysis.asc.
Please try to simulate the power in V1 and power in R1 since I am analyzing
the Power efficiency (Pout/Pin) of the circuit. Also if you try to simulate
using C = 16uF it's simulating just fine but it gives error when you try C =
17uF... You can try other value of C as well. It gives error for only some
values of C above 16uF.
Hope you can find out why it behaves as such..
Thanks so much for the help

Kind regards,
Micheline

--- In LTspice@..., "gasoltroll" <johan.lans@...> wrote:

Hi
i'm looking at an impedance curve of a non-ideal tantalum capacitor in LTSpice. The test circuit and impedance curve is seen in this screengrab:

The spice file is here .
So, the imdpedance curve shows the expected impedance minimum, but also an unexpected maximum at about 100MHz, where there is also a polarity switch in phase. This feature does not show up if I do an impedance plot in octave:


octave:1> f = [1000:1000:1e9];
octave:2> C = 2e-3C = 0.0020000
octave:3> R = 2e-3R = 0.0020000
octave:4> L = 1e-9L = 1.0000e-09
octave:5> z = R + f.*2*pi*j*L-1./(f.*2*pi*j*C)
octave:6> loglog(f,abs(z))
octave:7> semilogx(f,atand(imag(z)./real(z)))

Which result in these plots



The parameters in the octave code are the same as in LTSpice component. Anyone know where this comes from? The phases look pretty different, is there something wrong with the test circuit?

Hello Johann,

Please set a value for Cpar when you have set Lser.

Right-mouse-click on the capacitor. Then set the following.

Equivalent parallel capacitance(Cpar): 0p

Best regards,
Helmut

--- In LTspice@..., Tan Micheline Tambayong <micheline.tambayong@...> wrote:

Does anyone know what its means when LTspice give error:
"Singular matrix: check node n002
Iteration No. 1"

The circuit is made by AC voltage source, resistor (series with the voltage
source), bridge rectifier, capacitor, resistor paralleled with the capacitor
as a load at the output, and ground. The circuit is plotting and simulating
just fine for small value of capacitor. But when I increase the capacitor
value above 16uF, LTspice give the above error. But for some capacitor
values (eg. 20uF) it's fine again, and when I increase it again (eg.21uF),
it gives error again. So LTspice gives error for most of capacitor value
above 16uF but not all.. Also, for some value, it simulating but then the
plot stops in the middle. The value of the capacitor that gives an ok plot
and error are randoms (no pattern). So does anyone know, what's the reason
that the LTspice behaves like this?

Thanks in advance..

Kind regards,
Micheline

Hello Micheline,

This error message simply means that LTspice couldn't solve
the matrix. Maybe your circuit has an open nets.

Please upload your circuit to this group for a test to the
following location.

Files > Temp > yourcircuit.asc



Best regards,
Helmut

SPICE (and LTspice is no exception) can have additional shunt elements
from every node to ground, added to help convergence. ?I've kind of
lost track of exact details, over the years, but there can be a gshunt
(conductance) and a cshunt (capacitance) added to every node.

I think cshunt is resonating with the tantalum's inductance.

I don't know exactly where the value of this capacitance is set (other
than an .OPTIONS statement), but I saw in the "Hacks" tab of the
Control Panel, there is a setting for "Minimum shunt to main
capacitance ratio". ?Changing that number moves the parallel
resonance,?so I think it is the cause. ?If you make the "Hacks" value
very small, or zero, the curve looks like your Octave plot.
Andy

Does anyone know what its means when LTspice give error:
"Singular matrix: check node n002
Iteration No. 1"

The circuit is made by AC voltage source, resistor (series with the voltage
source), bridge rectifier, capacitor, resistor paralleled with the capacitor
as a load at the output, and ground. The circuit is plotting and simulating
just fine for small value of capacitor. But when I increase the capacitor
value above 16uF, LTspice give the above error. But for some capacitor
values (eg. 20uF) it's fine again, and when I increase it again (eg.21uF),
it gives error again. So LTspice gives error for most of capacitor value
above 16uF but not all.. Also, for some value, it simulating but then the
plot stops in the middle. The value of the capacitor that gives an ok plot
and error are randoms (no pattern). So does anyone know, what's the reason
that the LTspice behaves like this?

Thanks in advance..

Kind regards,
Micheline

--- In LTspice@..., "Tony Casey" <tony@...> wrote:

--- 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

Maybe I'm just a little bit lazy, since there are over 300 amplifiers to chose from in the LT selection window. Yes, they do have a one-line overview of the good specs, but being able to sort (like on the website selector page) is what I was hoping for.
Thanks to those who had other suggestions (universal opamp), but I wanted to "play with real opamps" before I ordered some samples for my breadboard.

really,

very kindly people here by

...

much more than in our german newsgroups :-)

regards, Leo ...