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Re: Waveform export from Mac LTspice?
Oops. Just found it. Start in the waveform window. Then Control Panel -> Waveforms -> Data Export Tool.
If you haven't noticed, the Control Panel options are different when you start from the waveform window than when you start from the schematic window. I seem to have a hard time remembering that. |
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Re: Varicap MVAM108
Hello Abu-Hafss,
You should firstly try on the manufacturer's web pages and then with Google. I made a short and looked with Google for the MVAM125. I found by luck an example with the diode's curve fit using the formula from the diode's SPICE model. http://www.qsl.net/in3otd/electronics/varactor_model/varactor_fitting.html Files > Lib > MVAM125_test.zip Best regards, Helmut |
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Re: Security?
Come on, folks!
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If a newbie comes along and asks about security of files on the website, that person deserves a straight answer. These days, with viruses and trojans and all that stuff seeming to be anywhere, it is a prudent question. Most newcomers to spice and many who have been around a while don't know that spice files are text files. As far as the casual observer might know, a .cir file could be just as able to carry bad stuff as a .jpg or .pdf or .xls or .docx any of the other complex file structures. In today's world, I would be a lot more cautious here than I am, if I were coming as a new user. There are several factors that make bad stuff pretty unlikely, here. Or, at other spice sites. 1. The target: anyone writing bad stuff wants big impact. spice has a very small user community, compared, say, to excel or word users. It is hard to imagine much general impact, beyond simple spite or maliciousness. 2. The kind of possible exploit is very limited. The language is pretty tight, and the parser can check for violations pretty easy. There should never be a "buffer over-run" exploit or anything like that. 3. spice files are not executables. They are interpreted by the the host application (a variant of Berkeley spice). There is a long history in spice, with all sorts of unwitting attempts at mucking it up. It is pretty bullet proof. You CAN have files that appear to be one thing while are really another (an exe masquerading as a txt file). The operating systems have put significant constraints on the ability of this exploit to operate. Not impossible, of course, but, generally, YOU Have to agree to run any downloaded executable.? So, the short answer is that, if you are concerned, YOU can open any spice file with a text editor and verify that it is what it says that it is. After a while, you will discover that its an extra effort that you really don't need to take. Jim Wagner Oregon Research Electronics On May 29, 2014, at 10:24 PM, analogspiceman@... [LTspice] wrote:
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Re: differimproved
Hello Marcel,
I only had commented it, because it's the default. I always have the defaults in the control settings of the SPICE tab. If you sometimes change the settings, then it makes sense to set it in the schematic. ?When one share a simulation to others it may be worth to mention that they should reset the SPICE settings in the Control Panel. Best regards, Helmut |
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Re: differimproved
Thanks Helmut! The result appears to be correct now?and is? of course much faster (10us step instead of 1us, 1s t_end instead of 10s). Is there a special reason to comment out "method=trap reltol=0.001", other that they are the default for LTSpice (not the case in my other, LTSpice file compatible, simulator)? -marcel |
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Re: differimproved
Hello Marcel,
I have improved your simulation settings. It's mostly not a good idea to use uic. One has to wait then that any bias capacitors reach it's steady state. uic should be only used as an exception if a simulation has convergence problems or one want to simulate the startup behavior. For the ladder case it's even better to ramp-up the supplies. 1. no uic 2. max time step 10u 3. .four set to 10 periods The reported THD is now 0.175%. Files > Temp > Best regards, Helmut |
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model for LI ion battery in Ltspice
I have been searching for a model of Li ion battery and found the model of a Saft battery. But the code on the schematic is so clumsy and also the results seems to be off.Can anybody plz upload any other model of a Li ion battery.If it is possible,you really will be a life saver.Thankyou. |
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Re: differimproved
> You forgot to include the models for the output transistors, QBD139 > and QBD140. Sorry, I'll fix that. > It's generally not a good idea to refer to unnamed nodes > (N007 and N008) in the plots, when you save the .PLT file True. BTW, my idea is to look at the peak difference between the input and output signal. In my case it is about 500uVpp for 5Vtt output. It looks like 3rd order distortion.?I don't see how?this could ever translate to 1.8% THD. > How are you measuring the THD? ?This is a transient analysis, which > makes me think you will do an FFT. ?If so, it is essential that you turn > off waveform compression: > .options plotwinsize=0 > This is quite possibly why your LTspice simulation has the distortion > it has. ?Look at the bottom of the Help page for Waveform Viewer > > Waveform Arithmetic, and note how the simulation there uses both > plotwinsize=0 and numdgt=15, to get the best waveform accuracy > for the FFT. Thank you. I tried this but it doesn't help at all. > You also ought to have many waveform points per sine wave. ? > Your simulation calls for a maximum timestep of 100us, which > means only 10 samples per cycle. ?It might work OK with that, > but I'd feel better with more samples per period. You nailed it. This is no problem in my other simulator (which explicitly interpolates the data before the FFT) but in LTSpice one apparently must rely on oversampling for reliable results. With 1 us max. stepsize I get very good?results (but it takes ages). With 100 us steptime even the INPUT voltage (the sine generator) has 1% THD :-) > Running your simulation with other output transistors, the > amplifier does not seem to be very symmetrical and it is > not biased right. ? It is ok for my BD139/140 models. I think 500 uV pp error is quite good at 5Vpp output. Of course it would be fun to improve that. > Why does C5 have an initial condition > of 7.5V ? ?I think that's wrong, given that the > supply voltage is 7.5V and that C5's voltage > ultimately needs to reach ~0V. You are completely right. Simple brain fart on my part. > Also, why use UIC? ?You have this great simulator which > can figure out the initial operating point for you; why not use it? I am not aware that LTSpice has a PSS algorithm? Thank you for the expert advice, it really helped! -marcel |
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Re: Is the Group down?
Well, it's back on-line, now. I wonder if anything is changed, though... Vlad ______________________ -- holding, among others: a universal analog/digital filter, block-level models for power electronics (and not only), math blocks with a more stream-lined approach, some digital ADC, DAC, (synchronous-)counter, JKflop, etc. |
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Re: Using parameters and functions when defining a plot
Hello You could add a few bits to the schematic, such as abs(v(c1)) with an ideal diode + capacitor, then use that voltage, say v(max), to divide the final answer, v(c1)/v(max). If you want to avoid doing this manually, everytime you plot v(c1), you could simply add a B-source to your liking with that expression.
There could be another solution with the integrated S&H, but that would require a clock, or others, it's just a suggestion. Vlad ______________________ -- holding, among others: a universal analog/digital filter, block-level models for power electronics (and not only), math blocks with a more stream-lined approach, some digital ADC, DAC, (synchronous-)counter, JKflop, etc. |
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Re: differimproved
Hi.
Your electronic scheme extremely unchancy. I have even said bad. The Modes of the second cascade are assigned resistor with nominal value 100kOhm. The Current aproximately is (Vcc-0.6V)/100K*Beta/2=(7.5-0.6)/100000*500/2=17.3mA (LTspice gave 15.6mA). At heating current will increase (since grows Beta). Will In addition give change the current scatter parameter input cascade. So I do not advise to do the real amplifier on your scheme. Bordodynov. |
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Re: Security?
Hello,
One has to distinguish between (LT)SPICE files and program files. Any LTspice related files (symbols, models, plot directives) can never have any virus. I don't know how Yahoo has checked the uploaded programs(.exe). The exe-programs have been mostly in the section Files>Util of this group. Best regards, Helmut |
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Re: How can I make my simulation oscillate like my poorly designed PC board does?
Hello Carl,
I am glad you were able to work out your mistake on your own.? I really, really do appreciate that.? LTspice is an amazingly capable processing tool, but the usual ³¦±ô¾±³¦³ó¨¦ homilies still apply, e.g. "garbage in -- garbage out." I very much would recommend that you explore how damaging the gate oscillation effect can grow as the power supply voltage is increased.? Try changing the 5 volt value of the supplies on your schematic to 25 volts and examine the ac voltage that LTspice predicts will appear on the gates and you will see why the series Q-damping resistor is absolutely essential. ---In LTspice@..., <carlvanwormer@...> wrote : Thanks for all of the help and suggestions!? I had the feedback going to the drain, instead of 5nH away from the drain.? I started noticing a little wiggle, and then changed parts until I was getting results similar to my bad PC board.? I noticed that the type of FET (model) made a big difference in the sensitivity to oscillation.? Once I got the "good" oscillations, I found that a series damping resistor could eliminate the effect.? In addition to lower inductance routing, the new layout will have the extra resistor to eliminate the possibility of this oscillation. I've uploaded a file demonstrating the cause and cure of the oscillation (Oscillating Miller FETs 03.asc).? Thanks for the education! Carl |
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Re: Security?
Good question, but alas, too late for you.? This Yahoo group is undoubtedly secretly, violently infected with untrustworthy viruses.? In fact, by reading this message you personally are probably fatally infected with the AIDS virus.? You are no doubt doomed, so please send all of your monetary assets to Yahoo groups immediately.
Okay, that was sarcasm, but it is messages like yours that lead me to avoid responding altogether on this group very much any more.? No doubt you cannot help being the way you are any more than I can help being the way I am. To give your original question a serious answer, it is mind-numbingly ignorant to think that SPICE code could possibly be infected with such viruses.? In the future, once you have gained some working experience with LTspice, you hopefully will come to appreciate why this is so. ---In LTspice@..., <ag6qo@...> wrote : Are the components etc uploaded here trustworthy? Have there been any incidents of viruses etc embedded in files uploaded here? Are there precautions taken to avoid it? |
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