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Re: inductance with a permeability in dependency of frequency
--- In LTspice@..., "sawreyrw" <sawreyrw@...> wrote:
The permeability of some magnetic core materials is highly frequency-dependent - a good example is the amorphous materials marketed as parts for common-mode chokes. At common test frequencies, these may measure ten to 100 times their effective inductance when applied in the narrow-band conducted emissions frequency range (100KHz-1MHz), where the impedance is most critical. RL |
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Re: OT/Left Field...
For the person who must run LTspice on a tablet there is the Microsoft
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Surface Pro. See: <> For comparison a 128Gb Iipad price is $799. Howard On 7/9/2013 12:40 PM, Andy wrote:
As you may know, Mike Engelhardt has said before that LTspice isn't going |
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Re: arbitrary solar cell model
What made your netlist confusing to me, where a schematic would have helped, is figuring out the interconnections between the subcircuits, and between them and the other elements. Having nodes marked as "OUTPUT" that are actually inputs to the subcircuit, does not help. Your original note talked about both series and parallel connections, so I expected to see both. Not seeing that, I had to do a bunch of tracing, mentally re-constructing the missing schematic, to figure out whether this was the series case or the parallel case. So a schematic definitely would have helped. It would have made it less confusing, not more. actually the output should not have the distortion in -1.8kA ! and it should continue constant like a diode :)But you never described how this "distortion" manifests itself. Specifically, what did LTspice calculate that differed from your hand calculations of your formulas at the same operating point? (Indeed, did you do any hand calculations at the point or points in question, that show what the signal or signals ought to be?) Saying that signals look funny is one thing. Saying that they are incorrect requires some proof. You have not offered any proof that LTspice's findings are incorrect. In doing that, I think that you would probably find where the error is. Regards. Andy |
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Re: arbitrary solar cell model
--- In LTspice@..., "hamed" <l0st_l0rd@...> wrote:
Agree, but it is teditious to debug and/or examine a *.CIR file. No one is interested in a .cir file. - as Rick sawreyrw said. No one will do that job for you. So if you cannot transform the *.CIR file to an *.ASC schematic you will not get much help! hws |
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Re: File of where the keyboard shortcuts are stored
scad3.ini is now named LTspiceIV.ini. I believe its location is $APPDATA$\LTspiceIV.ini. The exact location of $APPDATA$ is dependent on your version of Windows. On this computer, it defaults to C:\Users\<username>\AppData\Roaming\. Regards, Andy |
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File of where the keyboard shortcuts are stored
Hello. I once knew how to transfer the keyboard shortcuts from my desktop to my laptop of LTspice. I have searched for it and found instructions that say that a scad3.ini file is located in Windows, but that may be old...there is not such file.
Does anyone know where the keyboard shortcuts are stored, so that I may simply copy them to my other computer? Thanks for your help! |
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Re: arbitrary solar cell model
hamed <l0st_l0rd@...> wrote:
the reason that I use arbitrary model not a standard diode is that I cannot control temperature change for each solar cell in diode model.You can. See the Help utility: LTspice IV > LTspice > Circuit Elements > D. Diode Syntax: Dnnn anode cathode <model> [area] [off] [m=<val>] [n=<val>] [temp=<value>] See that last expression? That is the temperature you want that particular diode instance to have. It overrides the global temperature setting. Each diode can have its own temperature. (Didn't someone else in this thread already say that?) Regards, Andy |
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Re: arbitrary solar cell model
Dear Fred
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Thank you very much for your answer. the reason that I use arbitrary model not a standard diode is that I cannot control temperature change for each solar cell in diode model. Furthermore, the reason that grounds are different is that two cells are in series. Actually I should say that I am not so good in schematics environment and I am used to netlists while I can control the nodes easier. In this model by varying the temperature of each cell most of elements values will change and it is the reason that I cannot use the standard diode model. Kind regards Hamed --- In LTspice@..., "qrx3" <fredh@...> wrote:
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Re: arbitrary solar cell model
Sorry I mis-typed, you probably want to leave v(inp) alone (don't reference it to 'ref') but you do want to change v(internode) to v(internode,ref). There still seems to be some other problem, though, at temperatures other than 25. I don't have time to look any further right now.
--- In LTspice@..., "hamed" <l0st_l0rd@...> wrote: [snip]If you look at the standard diode formula I = Is * exp(qV/kT) it seems like the voltage -should- go up with increasing T, but that neglects the temperature dependence of Is, which is quite strong. If you don't model that then Voc will go up with temperature. Another reason to use the standard diode model. -Fred --- In LTspice@..., "qrx3" <fredh@...> wrote:
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Re: OT/Left Field...
As you may know, Mike Engelhardt has said before that LTspice isn't going to be ported to another platform or OS. That would be a major undertaking. If there exists anything similar to Wine for Linux that would allow Microsoft Windows programs to run on a tablet, however unlikely, that would be the easiest way to get LTspice itself running there. The problem I see with these new hardware platforms, is that they are so transient. What do you suppose their lifetime is? That fact alone makes porting a major project like LTspice, not worth the effort. There are a number of freeware and/or source-code-available programs out there, to do electronic circuit simulation, in addition to those in the Wikipedia article. But alas they aren't LTspice. Andy |
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Re: 74F and 74ACT models
At one time, T.I. and National Semi (which is now T.I.) had SPICE models for them. In a university project I should simulate and analyse the frequency spectrum and the cross talk characteristics by using these elements.If you mean crosstalk within a device (multiple elements of the same IC), that could be a problem, unless their models are that detailed. Most SPICE models are not. If you mean crosstalk in traces on your board, you can do that. Andy |
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Re: arbitrary solar cell model
Hello Hamed,
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While I would also advise you to use a standard diode model instead of building your own, I may be able to shed some light on your difficulty. Note that your derived values for ISC and VOC are generated in relation to the reference input 'ref'. However when you use these values in your formulae you are using the value relative to ground: log((v(isc)/{i0})+1) The same is true when you use the input voltage: (v(inp)*iscr)/1000) I have not tried to run your circuit, but I strongly suspect this is why it would work for a single cell where ref = ground and not for a second cell where ref != ground. I think the most sensible fix would be to reference eisc and evoc to ground instead of ref, so you can observe the values externally if you want and not have to subtract the ref voltage. Then change "v(inp)" for example to "v(inp,ref)" where needed. I suggest that if you had drawn this as a circuit instead of writing a netlist these issues would have been quickly apparent, but maybe not. Cheers, Fred --- In LTspice@..., "hamed" <l0st_l0rd@...> wrote:
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locking the graph vertical axis
Having used LTSPICE for some years now, I never satisfactorily solved this issue:
I have some circuits that have essentially 0 gain, plotted on dB scales - I get 100's of dB on the vertical axis. I can adjust the axis to display a meaningful range, but every time you run the simulator the scale is autoranged again. Clicking the tick box 'autorange' to not autorange is not effective here - every run get autoranged just the same. Is there any way of locking the y axis to the entered values - I' sure I must just be missing something....and yes I read the documentation as best as I could... Kevin. ________________________________ This e-mail message is confidential and for use by the addressee only. If you are not the intended recipient, you must not use, disclose, copy or forward this transmission. Please return the message to the sender by replying to it and then delete the message from your computer. Nujira Ltd shall not be held liable to any person resulting from the use of any information contained in this e-mail and shall not be liable to any person who acts or omits to do anything in reliance upon it. Nujira Ltd does not accept responsibility for changes made to this message after it was sent. |
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Re: inductance with a permeability in dependency of frequency
I sometimes use a 'linear' representation of inductors to speed analyses.
Try a ladder network of linear inductors and resistors. Just like in fitlering, you have to change the first and last components, sometimes the middle - think in terms of Tchebyschev(sp?) coefficients and you'll get the picture *IF* you do that, it only takes somethinge like 5 to 7 terms (note the odd numbers) to pretty accurately match the performance of chip ferrite beads. As you know, chip ferrite beads start out a little inductive and then turn resistive, but as the impedance goes higher with increasing frequency the impedance angle seems to maintain the same angle, almost like eddy current losses. The point is, using the array form of entering values and with a little bit of thinking; you can create subckts that match spec within about 1-5% over the spectrum, yet use LINEAR components - speeding up analyses to way faster than using the LaPlace equation form. which is the usual models given for these chips. --- alzie@... wrote: From: alzie <alzie@...> To: LTspice@... Subject: Re: [LTspice] Re: inductance with a permeability in dependency of frequency Date: Tue, 09 Jul 2013 09:48:53 -0400 |
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Re: inductance with a permeability in dependency of frequency
Hi Herbert
On 07/09/2013 12:45 AM, sawreyrw wrote: dows anybody have an idea for modelling a inductance with a A simple model would be an inductor in parallel with a resistor. Most ferrous cores behave well up to a cross over frequency at which the perm drops and they become very lossy. The loss dominates above that freq and the inductor looks pretty much like a resistor that is flat with freq. -- AC2CL I do not think there is any thrill that can go through the human heart like that felt by the inventor as he sees some creation of the brain unfolding to success... Such emotions make a man forget food, sleep, friends, love, everything. - Nikola Tesla |
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Re: arbitrary solar cell model
--- In LTspice@..., "Hhamed" <l0st_l0rd@...> wrote:
The fact is that here I cannot use the standard diode model whileDid you know that a particular instance of a diode may have its temperature set independently of the general circuit simulation temperature such that the diode temperature remains fixed while the temperature of the other devices are varied? D1 1 0 cell n={n} m={m} temp=50 ; diode temp fixed at 50 deg C But, by all means, if you wish, please do carry on with banging your head against your wall of overly complicated netlists and questionably reinvented diode equations. |
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Re: arbitrary solar cell model
Thank you very much dear friend( you did not mention your name)
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The fact is that here I cannot use the standard diode model while it is temperature dependent diode so I should mention the diode property. the point is that I should not see the distortion there but I see ! and I don't know where is the problem ! I also tried these formula in the circuit : gidiode internode ref value={i0*(exp(v(internode)/({vt}*(v(tcell)+273)))-1)} but the strange thing is that the by increasing the temperature, the open circuit voltage will increase which shouldn't be !!! Thanks for your answer regards Hamed --- In LTspice@..., "analogspiceman" <analogspiceman@...> wrote:
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Re: arbitrary solar cell model
--- In LTspice@..., "Hamed" <l0st_l0rd@...> wrote:
Is there some reason you model must be so complicated and do you really need to reinvent the diode model? Couldn't you do something like the following and put all us, your fellow group members and involuntary consumers of SPAM, out of our collective misery? [Or you could just feed us wafer-thin after-dinner mints... Gurgle, burp... Nah, I couldn't eat another thing, I'm absolutely stuffed! Now, SPAM off!] * Simple yet effective PV Array model (typical values) * * Rp sets voltage slope of curve * Rs sets current slope of curve * Isc is short circuit current * n = number of series cells * m = number of parallel strings .param Rp=1 Rs=3m Isc=10 n=60 m=1 I1 0 1 {Isc*m} D1 1 0 cell n={n} m={m} Rp 1 0 {Rp*n/m} .model cell d Rs={Rs} Is=315n n=1.26 Cjo=50u Tnom=25 Trs1=10m Trs2=0m1 |
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Re: arbitrary solar cell model
John Woodgate
In message <krgsbq+nfo3@...>, dated Tue, 9 Jul 2013, hamed <l0st_l0rd@...> writes:
Thanks friends for your responses but the point is that converting this circuit to schematics will make it more confusing.It couldn't possibly do so. If you want more help, please post 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 |
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Re: arbitrary solar cell model
Thanks friends for your responses but the point is that converting this circuit to schematics will make it more confusing.
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actually the output should not have the distortion in -1.8kA ! and it should continue constant like a diode :) kind regards Hamed --- In LTspice@..., John Woodgate <jmw@...> wrote:
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