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--- In LTspice@..., John Woodgate <jmw@...> wrote:

In message <ksdlam+2tic@...>, dated Sat, 20 Jul 2013, Helmut
<helmutsennewald@...> writes:

The answer is no.
Everything defined with .param will be evaluated at the beginning of a
simulation and is then constant for the whole simulation.

But is there another way to change K at a specified time during a .tran
simulation?
--
OOO - Own Opinions Only. See www.jmwa.demon.co.uk
Why is the stapler always empty just when you want it?

John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

Hello John,

One would have to make a transformer based ob B-sources plus
inductors.

Google: ideal transformer spice

Best regards,
Helmut

Hello,Helmut,
?
Thank you so much.
my problem has soleved!
?
Shukichi


________________________________
From: Helmut <helmutsennewald@...>
To: LTspice@...
Sent: Saturday, July 20, 2013 6:26 PM
Subject: [LTspice] Re: Measure statements description to find cut off frequency


?



--- In mailto:LTspice%40yahoogroups.com, "shukichi2079" <shukichi2079@...> wrote:

Hello.
Regarding to AC simulation.
I want to know cut off frequency
using ".measure" statements.
In LT spice help, I found how
to describe band-width but
I don't know how to describe
to find cut off frequency only.

if you know description it,
please teach me.

Regards.
Shukichi

Hello Shukichi,

Please take a look the examples from our Files-section.

Files > Tut > MEASURE > AC



Best regards,
Helmut




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

In message <ksdlam+2tic@...>, dated Sat, 20 Jul 2013, Helmut <helmutsennewald@...> writes:

The answer is no.
Everything defined with .param will be evaluated at the beginning of a simulation and is then constant for the whole simulation.

But is there another way to change K at a specified time during a .tran simulation?
--
OOO - Own Opinions Only. See www.jmwa.demon.co.uk
Why is the stapler always empty just when you want it?

John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

In message <MfjOdgDTQl6RFw$6@...>, dated Sat, 20 Jul 2013, John Woodgate <jmw@...> writes:

In message <ksdh55+evd7@...>, dated Sat, 20 Jul 2013, jean_claudeabeille <jean_claudeabeille@...> writes:

OK, I would like it.
I sent this text from yahoo mail and never received the answer. Fortunately I found it here. Problem is : I don't know how to join a schematic here while it's easy with yahoo mail. How can I proceed ?

Look at these links at the foot of each list message:

They were stripped out by the server. The important one is:



which takes you to the list's site front page.

To upload a schematic, go to the web site and click on 'Files' in the left column. On the Files page, scroll down to 'Temp' in the middle column and click on it. On the Temp page, click on 'Add file' at the top right of the middle column. Use, for example 'MPS4250 model.asc' as the filename.

Disregard the part headed 'Auto-send to members' (if it appears) and tick the box under 'Notification'. Then click on the blue 'Upload' box.

--
OOO - Own Opinions Only. See www.jmwa.demon.co.uk
Why is the stapler always empty just when you want it?

John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

--- In LTspice@..., "bryan.esteban@..." <bryan.esteban@...> wrote:

Greetings,

I'm interested in applying a step change to the coupling coefficient of two coupled inductors during transient analysis at a desired time. Is this something that can be done using the .func & .param commands?

Thanks in advance for any assistance rendered.

Bryan

Hello Bryan,

The answer is no.
Everything defined with .param will be evaluated at the beginning
of a simulation and is then constant for the whole simulation.

Best regards,
Helmut

--- In LTspice@..., "shukichi2079" <shukichi2079@...> wrote:

Hello.
Regarding to AC simulation.
I want to know cut off frequency
using ".measure" statements.
In LT spice help, I found how
to describe band-width but
I don't know how to describe
to find cut off frequency only.

if you know description it,
please teach me.

Regards.
Shukichi

Hello Shukichi,

Please take a look the examples from our Files-section.

Files > Tut > MEASURE > AC



Best regards,
Helmut

Hello.
Regarding to AC simulation.
I want to know cut off frequency
using ".measure" statements.
In LT spice help, I found how
to describe band-width but
I don't know how to describe
to find cut off frequency only.

if you know description it,
please teach me.

Regards.
Shukichi

In message <ksdh55+evd7@...>, dated Sat, 20 Jul 2013, jean_claudeabeille <jean_claudeabeille@...> writes:

OK, I would like it.
I sent this text from yahoo mail and never received the answer. Fortunately I found it here. Problem is : I don't know how to join a schematic here while it's easy with yahoo mail. How can I proceed ?

Look at these links at the foot of each list message:



To upload a schematic, go to the web site and click on 'Files' in the left column. On the Files page, scroll down to 'Temp' in the middle column and click on it. On the Temp page, click on 'Add file' at the top right of the middle column. Use, for example 'MPS4250 model.asc' as the filename.

Disregard the part headed 'Auto-send to members' (if it appears) and tick the box under 'Notification'. Then click on the blue 'Upload' box.
--
OOO - Own Opinions Only. See www.jmwa.demon.co.uk
Why is the stapler always empty just when you want it?

John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

--- In LTspice@..., John Woodgate <jmw@...> wrote:

In message <1374140838.88699.YahooMailNeo@...>,
dated Thu, 18 Jul 2013, abeillé jean-claude
<jean_claudeabeille@...> writes:

I am a french retired computer analyst and a music and
electonicsenthusiast. Please, will you excuse my english.

It is quite good.

For the moment, I try to understand how does work my amp with LTSpice.
Actually, after an error in handling, one channel failed and activated
a protection circuit (too much quiescent on one output stage polarity).
I tried to fix this but I failed and ordered a complete replacement
PCB. But I am curious and like to understand things. So I drawn the
circuit in LTSpice from the PCB and could not understand it in some places.

Please upload the circuit (we use the US term ''schematic' on this list)
to Files => Temp on the list's web site:

I asked Bob Cordell some help but he was to busy and answer me to read
chapter 1-4 from his book. OK. In fact, in LTSpicen there is almost no
quiescent current in output stage and the VBE spreader does not work at
all. I thought that some models where not correct but I don't know. I'm
deadlocked.

I expect we can help once we see the schematic.
--
OOO - Own Opinions Only. See www.jmwa.demon.co.uk
Why is the stapler always empty just when you want it?

John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

OK, I would like it.
I sent this text from yahoo mail and never received the answer. Fortunately I found it here.
Problem is : I don't know how to join a schematic here while it's easy with yahoo mail. How can I proceed ?

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

--- In LTspice@..., "oleka111" <oleka111@> wrote:

Nice to see that you spotted it too......
What if real circuit would behave the same way ?
Hope Linear will fix this issue soon.
I didn't post the original file, because everyone can load it as an LT's example named 3765.asc and see the effect of diminishing of the voltage feedback resistor.

Regards,
Olek A.

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

--- In LTspice@..., "oleka111" <oleka111@> wrote:

Hello,

Running an dc/dc example named 3765.asc with slightly lowered feedback resistor (4.42 --> 4.2k) gives Vout appr. several times bigger than expected.
Just the opposite what we should expect while lowering the feedback resistor.
It can be even dangerous to the sensitive load.

Why it behaves this way ?

Hello,

Well spotted. I have tried this distribution example circuit on two machines, and it behaves as you describe.

I swept the feedback resistor from 4k1 to 4k3 in 10R steps and found that the LTC3766 transitions from closed loop to open loop behaviour when the value goes below 4210R. Whether this a model error or not, I don't know, but the example circuit is clearly unsatisfactory.

I have reported this as a bug to Mike.

Regards,
Tony

I have received a response from Linear (not Mike - I think he must be on holiday).

Basically, what they say is that the behaviour is as expected, and related to the undervoltage lockout on Vcc, which is connected to the regulated output in this circuit, and that this is operating the device somehow incorrectly because of that.

However, the LTspice simulation is almost exactly the same as the application circuit in the datasheet (with the exception that the output is not floating), and the simulation would suggest it won't work as published with 5% resistors.

The datasheet says: the minimum Vcc voltage is 5V, and that the regulated DC voltage must be above this if it supplies Vcc directly, or an overvoltage condition can occur. So, this is kind of a known "feature". With zero tolerance resistors, the calculated regulated output voltage is (1 + 4.42k/604)*599.6mV, which is 4.987V, so this is never going to work in the real world.

This is what the LT response actually said:
"Alright the jig circuit shows that you can use 4.42KOhm, and it is not suppose to take that as the real design. If you want the design close to the scenario, you need to go through from more realistic perspective.

Anyway, the model is right, and the jig is right. If you argue that the circuit is not a robust design, that is not the issue of the model. Many times our jig circuits show simplified setup, for example, more ideal magnetic devices, no ESL of sensing resistor, down sized soft-start cap, etc. It is there for user to quickly pick up the fundamental features of the part, and we encourage users to design their applications based on that."

For what it's worth, I modified the schematic so that the Vcc pin was fed from a separate 5V supply and reduced the feedback resistor to 4k1 (from 4k42), and the output did regulate properly at 4.67V.

Hope that helps somebody.

Regards,
Tony

I have managed to separate Vcc pin to 5V as Tony suggested.
Now my feedback resistor is 2.7k , Vout plateau is 3.28V at 0.3ohm load.
Now it makes sense
Regards,
Olek A.

Hello Didier

The reason for that is because of the syntax for .func, it should be by the book:
.func f(x) {...}
not f(x)=...

There may also be some outdated symbols/libraries. I'll make the changes and update the files with the correct syntax later (but possibly much later).


Vlad

Greetings,

I'm interested in applying a step change to the coupling coefficient of two coupled inductors during transient analysis at a desired time. Is this something that can be done using the .func & .param commands?

Thanks in advance for any assistance rendered.

Bryan

--- In LTspice@..., Andy <Andrew.Ingraham@...> wrote:

Okkar Moe Myint <okkarmoemyint@...> wrote:

..

. I could not find the library for MAX4173H which is a high side current
sense.
...

This webpage:



has a "macromodel" (which is a SPICE model) for the MAX4173T. The
difference between the 'T' and the 'H' version seems to be the part's
voltage gain. If you can only use the 'H' version, it might be possible to
modify the 'T' version's macromodel.

Macromodels are models of simplified versions of the actual circuitry.
Sometimes a block, such as an op-amp, is represented by a VCVS, which
simulates faster than a couple dozen transistors that actually comprise the
op-amp.

This macromodel is a SPICE "subcircuit", so you would use it as a
subcircuit. There must be hundreds of messages already in this group about
how to use a subcircuit model in an LTspice simulation.

This webpage:



has an Orcad (PSPICE) library for the same part. The model looks very
similar. LTspice is very compatible with PSPICE, so that one probably
works just fine too.

Regards,
Andy

Hello,

I just reworked my example with for the MAX4173T.
Unfortunately I couldn't find a simple rework to make a F
or H model.

Files > Lib > MAX4173T_LTC6101



Best regards,
Helmut

In message <CALBs-Ti=EVmQ7Kze1GxnidYUebsgYMnm-M_Ne3BY9jBsRLbA4A@...>, dated Fri, 19 Jul 2013, Andy <Andrew.Ingraham@...> writes:

Is there a susceptance in LTspice, that i can direct use?


A capacitor, or an inductor, are susceptance elements.

I think the question is whether one can enter a susceptance value in a component's properties. I'm sure this isn't possible, but;

a) you never know what is in fact possible in LTspice;

b) you can overcome it because you can calculate the capacitance C or inductance L that has susceptance B at frequency f quite easily:

C = B/(2pi*f), L = 1/(2pi*f*B).

Elastance, anyone? (;-)
--
OOO - Own Opinions Only. See www.jmwa.demon.co.uk
Why is the stapler always empty just when you want it?

John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK

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

Now I know why I have seen LTspice only later in 2001.
Maybe our FAE overlooked my interest in LTspice. :-)

Hi Helmut,

I just corrected a major omission (our LTspice group!):

Okkar Moe Myint <okkarmoemyint@...> wrote:

..

. I could not find the library for MAX4173H which is a high side current
sense.
...

This webpage:



has a "macromodel" (which is a SPICE model) for the MAX4173T. The
difference between the 'T' and the 'H' version seems to be the part's
voltage gain. If you can only use the 'H' version, it might be possible to
modify the 'T' version's macromodel.

Macromodels are models of simplified versions of the actual circuitry.
Sometimes a block, such as an op-amp, is represented by a VCVS, which
simulates faster than a couple dozen transistors that actually comprise the
op-amp.

This macromodel is a SPICE "subcircuit", so you would use it as a
subcircuit. There must be hundreds of messages already in this group about
how to use a subcircuit model in an LTspice simulation.

This webpage:



has an Orcad (PSPICE) library for the same part. The model looks very
similar. LTspice is very compatible with PSPICE, so that one probably
works just fine too.

Regards,
Andy

--- In LTspice@..., "analogspiceman" <analogspiceman@...> wrote:

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

--- In LTspice@..., analogspiceman wrote:

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

I always wonder that 1999 was the "birth" of LTspice.
I personally discovered that LTspice is a SPICE program in
the summer 2001. I still believe that I was one of the early
adopters using it as a general SPICE program. Also the
discussions about LTspice started in 2001 in the usenet,
sci.electronics.design and sci.electronics.cad.

A trademark information search on "LTspice" yields:

First Use Anywhere: . .10/1/1999
First Use In Commerce: 10/1/1999

The Help about box shows a copyright back to 1998.

The earliest messages about SwitcherCAD III, SwitcherCAD3 or
LTspice that I could find were in June of 2001. Some trade
magazine articles about LTspice also came out in June 2001,
so LTspice must have been available in at least May 2001.
Perhaps it was quietly available in 2000. I might send Mike
a link to the LTwiki page and ask for his input (or perhaps
the question might be received more favorably coming from you).

Hello analogspiceman,

I have sent an email to Mike and asked him about comments and
corrections.

Thanks, Helmut. I went ahead and also sent him an email, but
your support is appreciated. ... What? He just now replied,
wrote that he's off to Australia, but answered with some
interesting tidbits (and will give a more complete answer when
he gets back.

"LTspice was released in Oct 1999 at a meeting of Linear
Technology's Field Application Engineers. They were then free
to give it to customers they met on a visit-by-visit basis."

Hello analogspiceman,

Now I know why I have seen LTspice only later in 2001. Maybe
our FAE overlooked my interest in LTspice. :-)

Best regards,
Helmut

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

--- In LTspice@..., analogspiceman wrote:

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

I always wonder that 1999 was the "birth" of LTspice.
I personally discovered that LTspice is a SPICE program in
the summer 2001. I still believe that I was one of the early
adopters using it as a general SPICE program. Also the
discussions about LTspice started in 2001 in the usenet,
sci.electronics.design and sci.electronics.cad.

A trademark information search on "LTspice" yields:

First Use Anywhere: . .10/1/1999
First Use In Commerce: 10/1/1999

The Help about box shows a copyright back to 1998.

The earliest messages about SwitcherCAD III, SwitcherCAD3 or
LTspice that I could find were in June of 2001. Some trade
magazine articles about LTspice also came out in June 2001,
so LTspice must have been available in at least May 2001.
Perhaps it was quietly available in 2000. I might send Mike
a link to the LTwiki page and ask for his input (or perhaps
the question might be received more favorably coming from you).

Hello analogspiceman,

I have sent an email to Mike and asked him about comments and
corrections.

Thanks, Helmut. I went ahead and also sent him an email, but
your support is appreciated. ... What? He just now replied,
wrote that he's off to Australia, but answered with some
interesting tidbits (and will give a more complete answer when
he gets back.

"LTspice was released in Oct 1999 at a meeting of Linear
Technology's Field Application Engineers. They were then free
to give it to customers they met on a visit-by-visit basis."

He <he.yang@...> wrote:

Is there a susceptance in LTspice, that i can direct use?


A capacitor, or an inductor, are susceptance elements.

You might want to make sure they have no parasitic resistances, so that
your component has only susceptance and no conductance. Unless you also
want it to have conductance.

Andy

--- In LTspice@..., "shravan.krishna7@..." <shravan.krishna7@...> wrote:

I am a beginner of LTspice. Please would someone tell the procedure of adding INA105 pspice model into LTspice?

Hello,

I have looked for similar part and found an example with the
INA132. It was easy to modify this part for teh INA105.

Files > Lib > INA105_test.zip


Open the symbol with the symbol editor of LTspice and study
the attributes and the "Netlist order" in the pins. This
netlist order is simply the order of the pins in .subckt.
It's not the name or number of these subcircuit-pins.

Best regards,
Helmut