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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

--- In LTspice@..., "Michi" <micheline.tambayong@...> 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

Hello,

The diode without an extra model has the default parameters.
You can find a short description about it in the Help-pages
of LTspice

Help: LTspice -> Circuit Elements -> D(iode)

Best regards,
Helmut

Yes I found that one, eg.1N914, 1N750 etc.. But I need to use the one that has Vthreshold = 0V. Do you know what type that gives that characteristic? If there isn't, do you know how to make it? What value of the parameter that I should put to get that V threshold = 0? It's because I tried the diode that already there in ltspice but the V threshold are around 0.6 or 0.5. There is no diode that has 0 Vthreshold. Is it impossible to make it?
Thanks

In message <j0oc0f+mjkp@...>, dated Wed, 27 Jul 2011, Michi <micheline.tambayong@...> writes:

There is no diode that has 0 Vthreshold. Is it impossible to make it?

It is possible to make a model in LTspice, but what is the point of simulations based on something that doesn't exist? It is not possible to make one in real life. (There are exotic, and probably never manufactured, devices that come close to a 'zero-threshold diode' but again, if you can't buy them, what is the point of simulating them?)

A practical near-zero threshold rectifier uses a real diode (better to use two) in the feedback loop of an op-amp. There are plenty of examples in the literature.
--
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.

--- In LTspice@..., "Michi" <micheline.tambayong> wrote:

But I need to use the one that has Vthreshold = 0V. Do you know
what type that gives that characteristic?

Yes, I know what type does exactly that because I used my super
power vision to read the topic on ideal diodes hidden deviously
in plain sight in the super unsecrete Help file. It was very
cruel of the programmers at LTC to actually expect you to read
and understand a straightforward explanation of the ideal diode.
Why they did not equip LTspice with precognitive online videos
I will never know. Why, setting up the ideal diode requires way
too many parameters - there must be at least one if not one.

Here is the mystery text from Help:

| There are two types of diodes available. One is a conduction
| region-wise linear model that yields a computationally light weight | representation of an idealized diode. [...] Below are the model
| parameters for this type of diode:
|
| Ron: Resistance in forward conduction; Default: 1 ohm

Who can decipher the meaning of this strange code?

How to make Ron=1m or Ron=1u instead?

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

--- In LTspice@..., "Michi" <micheline.tambayong> wrote:

But I need to use the one that has Vthreshold = 0V. Do you know
what type that gives that characteristic?

Yes, I know what type does exactly that because I used my super
power vision to read the topic on ideal diodes hidden deviously
in plain sight in the super unsecrete Help file. It was very
cruel of the programmers at LTC to actually expect you to read
and understand a straightforward explanation of the ideal diode.
Why they did not equip LTspice with precognitive online videos
I will never know. Why, setting up the ideal diode requires way
too many parameters - there must be at least one if not one.

Here is the mystery text from Help:

| There are two types of diodes available. One is a conduction
| region-wise linear model that yields a computationally
| lightweight representation of an idealized diode. [...]
| Below are the model parameters for this type of diode:
|
| Ron: Resistance in forward conduction; Default: 1 ohm

Who can decipher the meaning of this strange code?

How to make Ron=1m or Ron=1u instead?

Oh, the cruel Help programmers have confused me by including the
most important piece of information ON ANOTHER LINE!

| Vfwd: Forward threshold voltage to enter conduction; Default: 0V

Hi John Woodgate.
I once accidentally got ideal diode. When designing an integrated circuit test, I placed the structure - the Schottky diode 10x10 uMeter^2 to the guard ring. Got a diode Vfd = 0, and a breakdown voltage of 50 volts. After cutting the wafer diodes have been destroyed. Later obtained normal Schottky diodes.
Bordodynov.

27.07.2011, 11:19, "John Woodgate" <jmw@...>:

--- In LTspice@..., Alex Bordodunov wrote:

I once accidentally got ideal diode. When designing an integrated
circuit test, I placed the structure - the Schottky diode 10x10
uMeter^2 to the guard ring. Got a diode Vfd = 0, and a breakdown
voltage of 50 volts. After cutting the wafer diodes have been
destroyed. Later obtained normal Schottky diodes.

Bordodynov, strongingly I suspect work of cruel programmers. You
must contact Mooose and Squirrel immediately.

Hello Analogspiceman,
Where do you buy your super power vision and get the super unsecrete Help file ?
I missed them.
It's urgent.
Regards,
Philippe

--- In LTspice@..., "Michi" <micheline.tambayong@...> wrote:

Yes I found that one, eg.1N914, 1N750 etc.. But I need
to use the one that has Vthreshold = 0V. Do you know what
type that gives that characteristic? If there isn't, do
you know how to make it? What value of the parameter that
I should put to get that V threshold = 0? It's because
I tried the diode that already there in ltspice but the
V threshold are around 0.6 or 0.5. There is no diode
that has 0 Vthreshold. Is it impossible to make it?
Thanks

Hello Michi,

LTspice offers also a simplified(ideal) model. It has its own
set of parameters not available in standard SPICE.

There are a few more parameters available then shown below.
See the help pages of LTspice.

.model DIO D(Vfwd=0 Ron=1m)


I have made an example for you.

Files > Temp > ideal_diode.asc


Best regards,
Helmut

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

--- In LTspice@..., "Michi" <micheline.tambayong@> 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

Hello,

The diode without an extra model has the default parameters.
You can find a short description about it in the Help-pages
of LTspice

Help: LTspice -> Circuit Elements -> D(iode)

Best regards,
Helmut

Hi Helmut,
I'm so sorry that I haven't got the time to respond to the solution given
until now.
However, when I tried to open the link you gave me, I cannot find the file
ideal_diode.asc in it. Is it because it's already been removed and I am too
late to download it? If that's the case then can you please post it again?
I'm so sorry for the trouble. I'll be sure to check it immediately after I
got your reply.
Also I have another question. Do you know how to make an ideal Transformer?
(ie. transformer where coupling factor, k = 1, and N1=N2) What is the value
of k, and L that I should use? Because I try to find some info about it and
some said to use k=1 directly and use whatever value of L and some said that
I cannot actually use k=1 in LTSpice and the value of L should be large. So
can you please help me about this?
And the last question is that can you please tell me how to use integration
in the plot. I want to plot power, P = (1/T)*int(V*I) wrt to time, where T
is period, V is voltage at some node and I is the current. I manage to plot
V, I or even V*I all this time but when I tried to use the command sdt or
idt, the LTspice cannot recognise it. Please help me if you know how to do
this.

Also if anyone know about this please help me.

Thanks so very much for the help..

Kind regards,
Micheline

On Wed, Jul 27, 2011 at 9:54 PM, Helmut <helmutsennewald@...> wrote:

**


--- In LTspice@..., "Michi" <micheline.tambayong@...> wrote:

Yes I found that one, eg.1N914, 1N750 etc.. But I need
to use the one that has Vthreshold = 0V. Do you know what
type that gives that characteristic? If there isn't, do
you know how to make it? What value of the parameter that
I should put to get that V threshold = 0? It's because
I tried the diode that already there in ltspice but the
V threshold are around 0.6 or 0.5. There is no diode
that has 0 Vthreshold. Is it impossible to make it?
Thanks

Hello Michi,

LTspice offers also a simplified(ideal) model. It has its own
set of parameters not available in standard SPICE.

There are a few more parameters available then shown below.
See the help pages of LTspice.

.model DIO D(Vfwd=0 Ron=1m)

I have made an example for you.

Files > Temp > ideal_diode.asc


Best regards,
Helmut

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

--- In LTspice@..., "Michi" <micheline.tambayong@> 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

Hello,

The diode without an extra model has the default parameters.
You can find a short description about it in the Help-pages
of LTspice

Help: LTspice -> Circuit Elements -> D(iode)

Best regards,
Helmut

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

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

Hi Helmut,
I'm so sorry that I haven't got the time to respond to the solution given
until now.
However, when I tried to open the link you gave me, I cannot find the file
ideal_diode.asc in it. Is it because it's already been removed and I am too
late to download it? If that's the case then can you please post it again?
I'm so sorry for the trouble. I'll be sure to check it immediately after I
got your reply.
Also I have another question. Do you know how to make an ideal Transformer?
(ie. transformer where coupling factor, k = 1, and N1=N2) What is the value
of k, and L that I should use? Because I try to find some info about it and
some said to use k=1 directly and use whatever value of L and some said that
I cannot actually use k=1 in LTSpice and the value of L should be large. So
can you please help me about this?
And the last question is that can you please tell me how to use integration
in the plot. I want to plot power, P = (1/T)*int(V*I) wrt to time, where T
is period, V is voltage at some node and I is the current. I manage to plot
V, I or even V*I all this time but when I tried to use the command sdt or
idt, the LTspice cannot recognise it. Please help me if you know how to do
this.

Also if anyone know about this please help me.

Thanks so very much for the help..

Kind regards,
Micheline

Hello Micheline,

I always empty the Temp-folder after some time and move the
files to their "final" place. Then I make a new directory
listing where you can search for every file. Below is the
link to this file named "all_files.htm".



Please click on all_files.htm
Then search with your browser for your file. You will find it.
Click on it and then you will be in the correct directory.

I will answer the other questions later, but I hope that
somebody else will help before.

Best regards,
Helmut

On Wed, Jul 27, 2011 at 9:54 PM, Helmut <helmutsennewald@...> wrote:

**


--- In LTspice@..., "Michi" <micheline.tambayong@> wrote:

Yes I found that one, eg.1N914, 1N750 etc.. But I need
to use the one that has Vthreshold = 0V. Do you know what
type that gives that characteristic? If there isn't, do
you know how to make it? What value of the parameter that
I should put to get that V threshold = 0? It's because
I tried the diode that already there in ltspice but the
V threshold are around 0.6 or 0.5. There is no diode
that has 0 Vthreshold. Is it impossible to make it?
Thanks

Hello Michi,

LTspice offers also a simplified(ideal) model. It has its own
set of parameters not available in standard SPICE.

There are a few more parameters available then shown below.
See the help pages of LTspice.

.model DIO D(Vfwd=0 Ron=1m)

I have made an example for you.

Files > Temp > ideal_diode.asc


Best regards,
Helmut

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

--- In LTspice@..., "Michi" <micheline.tambayong@> 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

Hello,

The diode without an extra model has the default parameters.
You can find a short description about it in the Help-pages
of LTspice

Help: LTspice -> Circuit Elements -> D(iode)

Best regards,
Helmut

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

Hi Helmut,
I already found the file and it really works like how I wanted it!! Thanks
so much for the help with this..
I'm still new to LTspice so this really helps me.. Thanks so much for the
help with this ideal diode.
I'll wait for the solution on the other problems. Thanks!! =)

Kind regards,
Micheline

On Wed, Aug 3, 2011 at 1:08 AM, Helmut <helmutsennewald@...> wrote:

**


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

Hi Helmut,
I'm so sorry that I haven't got the time to respond to the solution given
until now.
However, when I tried to open the link you gave me, I cannot find the

file

ideal_diode.asc in it. Is it because it's already been removed and I am

too

late to download it? If that's the case then can you please post it

again?

I'm so sorry for the trouble. I'll be sure to check it immediately after

I

got your reply.
Also I have another question. Do you know how to make an ideal

Transformer?

(ie. transformer where coupling factor, k = 1, and N1=N2) What is the

value

of k, and L that I should use? Because I try to find some info about it

and

some said to use k=1 directly and use whatever value of L and some said

that

I cannot actually use k=1 in LTSpice and the value of L should be large.

So

can you please help me about this?
And the last question is that can you please tell me how to use

integration

in the plot. I want to plot power, P = (1/T)*int(V*I) wrt to time, where

T

is period, V is voltage at some node and I is the current. I manage to

plot

V, I or even V*I all this time but when I tried to use the command sdt or
idt, the LTspice cannot recognise it. Please help me if you know how to

do

this.

Also if anyone know about this please help me.

Thanks so very much for the help..

Kind regards,
Micheline

Hello Micheline,

I always empty the Temp-folder after some time and move the
files to their "final" place. Then I make a new directory
listing where you can search for every file. Below is the
link to this file named "all_files.htm".




Please click on all_files.htm
Then search with your browser for your file. You will find it.
Click on it and then you will be in the correct directory.

I will answer the other questions later, but I hope that
somebody else will help before.

Best regards,
Helmut

On Wed, Jul 27, 2011 at 9:54 PM, Helmut <helmutsennewald@...> wrote:

**


--- In LTspice@..., "Michi" <micheline.tambayong@> wrote:

Yes I found that one, eg.1N914, 1N750 etc.. But I need
to use the one that has Vthreshold = 0V. Do you know what
type that gives that characteristic? If there isn't, do
you know how to make it? What value of the parameter that
I should put to get that V threshold = 0? It's because
I tried the diode that already there in ltspice but the
V threshold are around 0.6 or 0.5. There is no diode
that has 0 Vthreshold. Is it impossible to make it?
Thanks

Hello Michi,

LTspice offers also a simplified(ideal) model. It has its own
set of parameters not available in standard SPICE.

There are a few more parameters available then shown below.
See the help pages of LTspice.

.model DIO D(Vfwd=0 Ron=1m)

I have made an example for you.

Files > Temp > ideal_diode.asc


Best regards,
Helmut

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

--- In LTspice@..., "Michi" <micheline.tambayong@>

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

Hello,

The diode without an extra model has the default parameters.
You can find a short description about it in the Help-pages
of LTspice

Help: LTspice -> Circuit Elements -> D(iode)

Best regards,
Helmut

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

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

Hi Helmut,
I'm so sorry that I haven't got the time to respond to the solution given
until now.
However, when I tried to open the link you gave me, I cannot find the file
ideal_diode.asc in it. Is it because it's already been removed and I am too
late to download it? If that's the case then can you please post it again?
I'm so sorry for the trouble. I'll be sure to check it immediately after I
got your reply.
Also I have another question. Do you know how to make an ideal Transformer?
(ie. transformer where coupling factor, k = 1, and N1=N2) What is the value
of k, and L that I should use? Because I try to find some info about it and
some said to use k=1 directly and use whatever value of L and some said that
I cannot actually use k=1 in LTSpice and the value of L should be large. So
can you please help me about this?
And the last question is that can you please tell me how to use integration
in the plot. I want to plot power, P = (1/T)*int(V*I) wrt to time, where T
is period, V is voltage at some node and I is the current. I manage to plot
V, I or even V*I all this time but when I tried to use the command sdt or
idt, the LTspice cannot recognise it. Please help me if you know how to do
this.

Also if anyone know about this please help me.

Thanks so very much for the help..

Kind regards,
Micheline

Micheline,

The answers to your last 2 questions can be found in the LTspice help file. (You shoud really read the help file, because there is lots of good information in it.)

LTspice has a great feature for plotting power, and it can give you a numerical value of power. Note that you need to plot an integer number of cycles. See Data Trace Selection under Waveform Viewer.

The FAQs in the help file covers a transformer. It is not an ideal transformer, because the magnetizing inductance is finite; however, this is more reasonable than an infinite value. Make Lp equal to the magnetizing inductance. Note that the inductance ratio should be N**2 and the voltage ratio is N.

Rick

--- In mail@..., Alex Bordodunov wrote:

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

--- In LTspice@..., Alex Bordodunov wrote:

I once accidentally got ideal diode. When designing an integrated
circuit test, I placed the structure - the Schottky diode 10x10
uMeter^2 to the guard ring. Got a diode Vfd = 0, and a breakdown
voltage of 50 volts. After cutting the wafer diodes have been
destroyed. Later obtained normal Schottky diodes.

Bordodynov, strongingly I suspect work of cruel programmers. You
must contact Mooose and Squirrel immediately.

Thank you for the warning. I discovered that my YAHOO group
letters were to the general access to the Internet. Available,
and my two e-mail address. You called the two names. Who is it?
They are involved in groups in YAHOO? Could not you give address
details?

Regards. Bordodynov.

Alex, first let me thank you for your many ongoing contributions to
our group. Many Russian language speakers, especially those living
in the USA, know (fondly) of Mooose and Squirrel. Perhaps this is
less likely for those who have always lived elsewhere. I think
you too might like Mooose and Squirrel once you have gotten to
know them better:





Regards -- analogspiceman

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

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

wrote:

Hi Helmut,
I'm so sorry that I haven't got the time to respond to the solution given
until now.
However, when I tried to open the link you gave me, I cannot find the file
ideal_diode.asc in it. Is it because it's already been removed and I am too
late to download it? If that's the case then can you please post it again?
I'm so sorry for the trouble. I'll be sure to check it immediately after I
got your reply.
Also I have another question. Do you know how to make an ideal Transformer?
(ie. transformer where coupling factor, k = 1, and N1=N2) What is the value
of k, and L that I should use? Because I try to find some info about it and
some said to use k=1 directly and use whatever value of L and some said that
I cannot actually use k=1 in LTSpice and the value of L should be large. So
can you please help me about this?
And the last question is that can you please tell me how to use integration
in the plot. I want to plot power, P = (1/T)*int(V*I) wrt to time, where T
is period, V is voltage at some node and I is the current. I manage to plot
V, I or even V*I all this time but when I tried to use the command sdt or
idt, the LTspice cannot recognise it. Please help me if you know how to do
this.

Also if anyone know about this please help me.

Thanks so very much for the help..

Kind regards,
Micheline

Hello Micheline,

I always empty the Temp-folder after some time and move the
files to their "final" place. Then I make a new directory
listing where you can search for every file. Below is the
link to this file named "all_files.htm".



Please click on all_files.htm
Then search with your browser for your file. You will find it.
Click on it and then you will be in the correct directory.

I will answer the other questions later, but I hope that
somebody else will help before.

Best regards,
Helmut

Hello Micheline,

When you need a transformer, just place inductors on the
schematic and couple the inductors with a K SPICE-directive.

With 2 inductors:

K1 L1 L2 1

With 3 inductors:

K1 L1 L2 L3 1

The ratio of inductance is the squared ratio of the voltage
ratio.
Example: 2:1 transformer

If the primary inductance is 1mH, then the secondary is 0.25mH
which 1/2^2=1/4 .



Instantaneous power can be directly plotted.

RUN the simulation.
Press the Alt-key while moving the mouse cursor over a
component. The cursor will change to a thermometer.
Now Left-lick, LTspice will plot the formula for the power
dissipation of this component.
If you want see the average power, then make the waveform
window active. Ctrl-Left-click on the plot label near the top of
the waveform. A small window will pop-up showing average power.
If your waveform is periodic, you should limit the waveform
window to an integer number of cycles to get precise results.

Best regards,
Helmut

Hi Helmut and Rick,

Thanks for the answer to the transformer problem. It works.. As long as I
use K = 1, the behaviour of the transformer will be an ideal one ( Zp/Zs =
(Vp/Vs)**2) so thanks for that.

However, I tried to plot the power using the one you told me. Using the Alt
and then click the cursor on the component. However when I press Alt-key, I
cannot find any thermometer cursor in the circuit. So what should I do with
in this case?
I can plot the power using the usual V*I (it gives Watt as the unit in the
plot) but I don't think this expression is correct since the circuit use AC
voltage, transformer, diode, capacitor and resistor.
To make it clearer, I attached the circuit I make. And in that circuit I
want to plot the power across R1 (load) so that later I can calculate the
Power efficiency (Pout/Pin). I am thinking of using Power = Integration
(I(R1)*V(R1)) but I don't know how to do the integration part in the plot.
Is there any other way to do it?

Thanks

Kind regards,
Micheline

Hello Micheline,

I attached the circuit I make

I don't got your circuit. because it's no more be attached in
the the Yahoo group's messages. You have to upload it to the
folder shown below.

Files > Temp


Best regards,
Helmut


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

Hi Helmut and Rick,

Thanks for the answer to the transformer problem. It works.. As long as I
use K = 1, the behaviour of the transformer will be an ideal one ( Zp/Zs =
(Vp/Vs)**2) so thanks for that.

However, I tried to plot the power using the one you told me. Using the Alt
and then click the cursor on the component. However when I press Alt-key, I
cannot find any thermometer cursor in the circuit. So what should I do with
in this case?
I can plot the power using the usual V*I (it gives Watt as the unit in the
plot) but I don't think this expression is correct since the circuit use AC
voltage, transformer, diode, capacitor and resistor.
To make it clearer, I attached the circuit I make. And in that circuit I
want to plot the power across R1 (load) so that later I can calculate the
Power efficiency (Pout/Pin). I am thinking of using Power = Integration
(I(R1)*V(R1)) but I don't know how to do the integration part in the plot.
Is there any other way to do it?

Thanks

Kind regards,
Micheline

On Wed, Aug 3, 2011 at 5:49 AM, Helmut <helmutsennewald@...> wrote:

**


Re: Ideal diode

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

--- In LTspice@..., Tan Micheline Tambayong

<micheline.tambayong@>
wrote:

Hi Helmut,
I'm so sorry that I haven't got the time to respond to the solution

given

until now.
However, when I tried to open the link you gave me, I cannot find the

file

ideal_diode.asc in it. Is it because it's already been removed and I am

too

late to download it? If that's the case then can you please post it

again?

I'm so sorry for the trouble. I'll be sure to check it immediately

after I

got your reply.
Also I have another question. Do you know how to make an ideal

Transformer?

(ie. transformer where coupling factor, k = 1, and N1=N2) What is the

value

of k, and L that I should use? Because I try to find some info about it

and

some said to use k=1 directly and use whatever value of L and some said

that

I cannot actually use k=1 in LTSpice and the value of L should be

large. So

can you please help me about this?
And the last question is that can you please tell me how to use

integration

in the plot. I want to plot power, P = (1/T)*int(V*I) wrt to time,

where T

is period, V is voltage at some node and I is the current. I manage to

plot

V, I or even V*I all this time but when I tried to use the command sdt

or

idt, the LTspice cannot recognise it. Please help me if you know how to

do

this.

Also if anyone know about this please help me.

Thanks so very much for the help..

Kind regards,
Micheline

Hello Micheline,

I always empty the Temp-folder after some time and move the
files to their "final" place. Then I make a new directory
listing where you can search for every file. Below is the
link to this file named "all_files.htm".

Please click on all_files.htm
Then search with your browser for your file. You will find it.
Click on it and then you will be in the correct directory.

I will answer the other questions later, but I hope that
somebody else will help before.

Best regards,
Helmut

Hello Micheline,

When you need a transformer, just place inductors on the
schematic and couple the inductors with a K SPICE-directive.

With 2 inductors:

K1 L1 L2 1

With 3 inductors:

K1 L1 L2 L3 1

The ratio of inductance is the squared ratio of the voltage
ratio.
Example: 2:1 transformer

If the primary inductance is 1mH, then the secondary is 0.25mH
which 1/2^2=1/4 .

Instantaneous power can be directly plotted.

RUN the simulation.
Press the Alt-key while moving the mouse cursor over a
component. The cursor will change to a thermometer.
Now Left-lick, LTspice will plot the formula for the power
dissipation of this component.
If you want see the average power, then make the waveform
window active. Ctrl-Left-click on the plot label near the top of

the waveform. A small window will pop-up showing average power.
If your waveform is periodic, you should limit the waveform
window to an integer number of cycles to get precise results.

Best regards,
Helmut

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

Hi Helmut and Rick,

Thanks for the answer to the transformer problem. It works.. As long as I
use K = 1, the behaviour of the transformer will be an ideal one ( Zp/Zs =
(Vp/Vs)**2) so thanks for that.

However, I tried to plot the power using the one you told me. Using the Alt
and then click the cursor on the component. However when I press Alt-key, I
cannot find any thermometer cursor in the circuit. So what should I do with
in this case?
I can plot the power using the usual V*I (it gives Watt as the unit in the
plot) but I don't think this expression is correct since the circuit use AC
voltage, transformer, diode, capacitor and resistor.
To make it clearer, I attached the circuit I make. And in that circuit I
want to plot the power across R1 (load) so that later I can calculate the
Power efficiency (Pout/Pin). I am thinking of using Power = Integration
(I(R1)*V(R1)) but I don't know how to do the integration part in the plot.
Is there any other way to do it?

Thanks

Kind regards,
Micheline

Micheline,

I don't know why you can't get the thermometer. Obviously, you are saving device currents, because you can plot V*I. I assume you have the schematic window active. If you plot an integer number of cycles of V*I, you can get a numerical value for the average power by placing your cursor over the plot label and pressing control click right. (You can plot an integer number of cycle by manually selecting the time axis.) V*I is instantaneous power so the average over an integer number of cycles is the power consumed. It doesn't matter, if V and I are sinusoidal or not.

You cannot attach files to messages to this group. Instead, you need to post them to the Files > Temp folder. Select Files > Temp on the left side of any page in the group.

Rick

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

Hello Micheline,

I attached the circuit I make

I don't got your circuit. because it's no more be attached in
the the Yahoo group's messages. You have to upload it to the
folder shown below.

Files > Temp


Best regards,
Helmut

Hello Micheline,

I have just discovered a screenshot of your schematic in my
private email.

There will be no automatic power display available, because
you have used the .AC simulation.

Your circuit contains a rectifier. It doesn't make sense to use
.AC analysis in such a nonlinear circuit. Instead you have to
use the .TRAN analysis.

When you upload a file, it should be the schematic file(.asc)
and not a picture/screenshot.

Best regards,
Helmut

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

Hi Helmut and Rick,

Thanks for the answer to the transformer problem. It works.. As long as I
use K = 1, the behaviour of the transformer will be an ideal one ( Zp/Zs =
(Vp/Vs)**2) so thanks for that.

However, I tried to plot the power using the one you told me. Using the Alt
and then click the cursor on the component. However when I press Alt-key, I
cannot find any thermometer cursor in the circuit. So what should I do with
in this case?
I can plot the power using the usual V*I (it gives Watt as the unit in the
plot) but I don't think this expression is correct since the circuit use AC
voltage, transformer, diode, capacitor and resistor.
To make it clearer, I attached the circuit I make. And in that circuit I
want to plot the power across R1 (load) so that later I can calculate the
Power efficiency (Pout/Pin). I am thinking of using Power = Integration
(I(R1)*V(R1)) but I don't know how to do the integration part in the plot.
Is there any other way to do it?

Thanks

Kind regards,
Micheline

On Wed, Aug 3, 2011 at 5:49 AM, Helmut <helmutsennewald@> wrote:

**


Re: Ideal diode

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

--- In LTspice@..., Tan Micheline Tambayong

<micheline.tambayong@>
wrote:

Hi Helmut,
I'm so sorry that I haven't got the time to respond to the solution

given

until now.
However, when I tried to open the link you gave me, I cannot find the

file

ideal_diode.asc in it. Is it because it's already been removed and I am

too

late to download it? If that's the case then can you please post it

again?

I'm so sorry for the trouble. I'll be sure to check it immediately

after I

got your reply.
Also I have another question. Do you know how to make an ideal

Transformer?

(ie. transformer where coupling factor, k = 1, and N1=N2) What is the

value

of k, and L that I should use? Because I try to find some info about it

and

some said to use k=1 directly and use whatever value of L and some said

that

I cannot actually use k=1 in LTSpice and the value of L should be

large. So

can you please help me about this?
And the last question is that can you please tell me how to use

integration

in the plot. I want to plot power, P = (1/T)*int(V*I) wrt to time,

where T

is period, V is voltage at some node and I is the current. I manage to

plot

V, I or even V*I all this time but when I tried to use the command sdt

or

idt, the LTspice cannot recognise it. Please help me if you know how to

do

this.

Also if anyone know about this please help me.

Thanks so very much for the help..

Kind regards,
Micheline

Hello Micheline,

I always empty the Temp-folder after some time and move the
files to their "final" place. Then I make a new directory
listing where you can search for every file. Below is the
link to this file named "all_files.htm".

Please click on all_files.htm
Then search with your browser for your file. You will find it.
Click on it and then you will be in the correct directory.

I will answer the other questions later, but I hope that
somebody else will help before.

Best regards,
Helmut

Hello Micheline,

When you need a transformer, just place inductors on the
schematic and couple the inductors with a K SPICE-directive.

With 2 inductors:

K1 L1 L2 1

With 3 inductors:

K1 L1 L2 L3 1

The ratio of inductance is the squared ratio of the voltage
ratio.
Example: 2:1 transformer

If the primary inductance is 1mH, then the secondary is 0.25mH
which 1/2^2=1/4 .

Instantaneous power can be directly plotted.

RUN the simulation.
Press the Alt-key while moving the mouse cursor over a
component. The cursor will change to a thermometer.
Now Left-lick, LTspice will plot the formula for the power
dissipation of this component.
If you want see the average power, then make the waveform
window active. Ctrl-Left-click on the plot label near the top of

the waveform. A small window will pop-up showing average power.
If your waveform is periodic, you should limit the waveform
window to an integer number of cycles to get precise results.

Best regards,
Helmut

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