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Re: Simulation Editor setting time span
John Woodgate
In message <l9kpmp+p6b0fl@...>, dated Fri, 27 Dec 2013,
grampastentis@... writes: I have a circuit that?uses a 556 and a variable resistor to?output toIf you mean it's 'flashing' in milliseconds, you probably have a wrong resistor or capacitor value. If you had uploaded your .asc file, we could be sure. To get seconds you need resistors of Xmeg values and capacitors of Yu values. You can get oscilloscope apps for smartphones and laptops, of course, some free or very low price. Laptops are easier to connect to. -- OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk Nondum ex silvis sumus John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK |
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Re: IR2153 Model
John Woodgate
In message <l9kqs5+kbtnei@...>, dated Fri, 27 Dec 2013, seenthis1@... writes:
Fatal Error: Could not open library file "Dead_Time.sub"Can you see a file called that in the folder where you have the .asc? If it was not in a .zip archive that you downloaded, the problem is that the zip is incomplete - it does occasionally happen. I can't find it anywhere. Maybe Helmut can tell you where to find it. -- OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk Nondum ex silvis sumus John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK |
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Re: IR2153 Model
Hi Andy, ? Thanks for the reply. ? Yes I have the schematic in the same folder as the model files but still no luck. ? I get the same problem when I try to run the IR2153_IC asc supplied with the model files. ? I get a text document error: ? Fatal Error: Could not open library file "Dead_Time.sub" ? Not sure what to do, could you try the model & the asc & see how you go with it? ? I would like to get it working if I can. ? Donna ? |
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Re: Simulation Editor setting time span
¿ªÔÆÌåÓýYou generally cannot specify the time step in spice simulators in general or in LTspice in particular.? The simulator takes big time steps when things are changing slowly and small steps when the situation is evolving rapidly.? You do have some control over the scaling on the horizontal axis after the simulation while plotting results. ? Your circuit may not be working due to leakage currents.? What is the largest resistor you are using? ? You can use the sound card on your computer as a (crude) oscilloscope.? You can even do things like plug a light sensor into the microphone jack and ¡°listen¡± to the LED driven by the 556. ? From: LTspice@... [mailto:LTspice@...]
On Behalf Of grampastentis@...
Sent: Friday, December 27, 2013 12:59 PM To: LTspice@... Subject: [LTspice] Simulation Editor setting time span ? ? I have a circuit that?uses a 556 and a variable resistor to?output to an LED 2 to?10?times per second. The LTSpice simulator is running in milliseconds and I would like to run in seconds instead. I have looked everywhere for the answer before posting so that I may avoid any snide remarks. I teach basic electronics to at-risk kids in my home and I can't afford a silly scope so I am learning LTSpice to show my kids the circuit behavior of what they breadboard before they solder the components. We have succeeded in getting?faster timer circuits to work but we are stumped on this one. Thank You??
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Simulation Editor setting time span
I have a circuit that?uses a 556 and a variable resistor to?output to an LED 2 to?10?times per second. The LTSpice simulator is running in milliseconds and I would like to run in seconds instead. I have looked everywhere for the answer before posting so that I may avoid any snide remarks. I teach basic electronics to at-risk kids in my home and I can't afford a silly scope so I am learning LTSpice to show my kids the circuit behavior of what they breadboard before they solder the components. We have succeeded in getting?faster timer circuits to work but we are stumped on this one. Thank You?? |
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Re: IR2153 Model
Donna wrote: ? "Hi, I downloaded the IR2153 Model from the Library but I have an issue when trying to run the simulation? ? I get a message saying: ? Could not open library file "Dead_Time.sub" ? I can't seem to find this file or fix the problem, so I was wondering if someone could help me please." Unzip the file. ?The contents need to go in the same directory (folder) where your schematics are. ?Do not attempt to put them anywhere in or under LTspice's libraries, nor anywhere in Windows' "Program Files" directory tree. Regards, Andy |
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IR2153 Model
Hi, I downloaded the IR2153 Model from the Library but I have an issue when trying to run?the simulation? ? I get a message saying: ? Could not open library file "Dead_Time.sub" ? I can't seem to find this file or fix the problem, so I was wondering if someone could help me please. ? I was hoping for a IR2155 Model if someone has one? ? Donna ? ? |
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Re: OS X No Icons Bug
Hello Dale,
It's intentional as it is. Please read also my other comments in the Files section.. http://groups.yahoo.com/neo/groups/LTspice/files/MAC/Functions%20in%20different%20places/ Special hints for MAC-LTspice MAC-LTspice doesn't have a menu-bar with all these commands. Please use the function keys. It will need a little bit exercise until you can quickly work with this function-key method. F2 Get components F3 Draw wires F4 Label net F5 Delete F6 Copy F7 Move F8 Drag F9 Undo Shift F9? Redo Spacebar Zoom to full extent s? Enter Spice Directive t? Enter comment Draw a wire in the direction of 45 degree: F3 Now hold the Shift-key while drawing the wire with any angle .lib name or .lib ./name Normally .lib filename works. I remember one case when I needed .lib ./filename Dialog windows for the analysis .TRAN, AC, .NOISE, .DC, .TF, .OP Press the key s to get the dialog window for SPICE-lines. Now "right mouse click" in this dialog window. Follow "Help me edit -> op Analysis command". Polarized electrolytic cap? F2 polcap There are even more nice symbols in [Misc], e. g. a European resistor symbol. F2 "Misc"? -> European Resistor My personal experience. MAC-LTspice is 64bit code and runs at least as fast as the WIN version. The only drawback is the slow speed when you zoom-in or zoom-out. Mike told me that he can't improve this the next few months. I missed the toolbar at the beginning. After I exercised the Fx function keys, I am quick with this Fx method too. Best regards, Helmut |
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Re: power dependent resistor - thermodynamic model
I will try to run LTSpice with command line and use .savebias/.loadbias to restore all nodes settings from previous run. Labview (or Scilab ) will compute physical parameters and update the netlist. I think I will face some convergence issues ... Let?s see. Regards. Micha |
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OS X No Icons Bug
Hi all,
I just realized there was a OS X-native version yesterday, so apologies if this is a newbie question: the only 'buttons' available at the top of the schematic window are run, stop, and control panel. Shortcuts (like F2 for add component) are available, so it's not the end of the world, but is there a fix for this? Macbook Late 2009 Intel Core Duo 2.26GHz 4GB RAM OS X 10.9 LTSpice build 12/19/2013, updated via gui. |
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Re: LTSpice mosfet models
'bkim125' wrote, "P.S. I am new to LTspice, so forgive me for the naivete of my questions. Clarifications on my understanding can be much appreciated." The difference between the "nmos" and "nmos4" in LTspice is simply whether the fourth (substrate or bulk) node is included as a separate node. ?In the "nmos" (and "pmos") devices, the substrate is connected internally to the source pin. All MOSFETs, like all bipolar transistors and diodes, need a separate .MODEL statement, which contains most of the parameters that describe the transistor or diode. ?The .MODEL statement can either be pasted onto your schematic, or referenced as a separate text file using an .INCLUDE statement on the schematic. For MOSFETs, "level" is one of the parameters of the .MODEL statement. ?I believe the default is LEVEL=1 (Shichman-Hodges model). LTspice comes with a collection of pre-defined transistor and diode types. ?Using them automatically loads the appropriate .MODEL statement for that transistor. ?To access these, right-click on the transistor or diode symbol and select "Pick New MOSFET" (or "Pick New Transistor" or Diode). ?This option doesn't exist for the "nmos4", "pmos4", "npn4", or "pnp4" devices because there are no pre-defined models for such parts, which are assumed to be integrated parts that you can't buy separately because they are part of an IC. When you don't select one of the pre-defined transistors, and don't provide a .MODEL statement for the part you have in mind, LTspice loads a default .MODEL statement and you get all default values. ?See LTspice's Help pages for the table of parameters and what their default values will be. Note that many MOSFETs also require channel width (W) and length (L) (and drain and source area and perimeter) values, to be provided. ?Generally speaking, these values are needed for MOSFETs that are part of an IC, but not for separate MOSFET components. ?Those values are usually specified as parameters attached to the transistor symbol itself, not in the .MODEL statement; but the .MODEL statement has default values in case they are omitted from the MOSFET symbol. Regards, Andy |
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Re: LTSpice mosfet models
Hello,
Maybe this gives you a first idea. http://www-inst.eecs.berkeley.edu/~ee105/fa98/lectures_fall_98/092298_lecture13.pdf Then continue here especially follow the link "LTspice" on this page: http://cmosedu.com/ Many models have been developed over the last thirty years. First we only had level 1, 2 and 3. The latest are the BSIM models. The model numbers are differently numbered among the SPICE programs. Most of the (LT)SPICE users never look into these details. They simply download the model from the manufacturer and use it as it is. SPICE wouldn't have been successful in board level simulations without this simplicity. I and also most LTspice users simulate on board level. Best regards, Helmut |
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Re: JFET Model
John Woodgate
In message <52BC2285.9070201@...>, dated Thu, 26 Dec 2013,
Winfield Hill <hill@...> writes: ?Well, I always say check your model against bench measurements beforeAnd vice-versa. I recently traced a difference between simulation and real life to a fault in real life - a 10 ohm resistor where a 100 ohm should have been. -- OOO - Own Opinions Only. With best wishes. See www.jmwa.demon.co.uk Nondum ex silvis sumus John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK |
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Re: JFET Model
¿ªÔÆÌåÓý?Well, I always say check your model against bench measurements before placing much reliance on any SPICE results.? As for FET capacitance with voltage, that's especially true! I've made plenty of measurements to back up that assertion. If the OP has a specific part he's interested in maybe I can take some measurements so we can test this issue.-- - Win Winfield Hill Rowland Institute at Harvard 100 Edwin Land Blvd Cambridge, MA 02142 617-497-4670 |
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LTSpice mosfet models
I have just downloaded the LTSpice and I have been playing around with the program.? I am currently trying do a common source amplifier design using a MOS, particularly for analog ic's. I notice that there are two components that are related to MOSFETs, "nmos" and "nmos4". I decided to use the nmos4 and it seems to me that the parasitic capacitances are not included. Is there a place where I can download a mosfet model which has all the parasitic capacitances built in?? Also, I have read up on the user's manual covering the topic of mosfets and it seems to me that there is this parameter called "level" which allows you to specify what sort of mosfet model you want (ex: Hodges, BSIM, ekv). I have been trying to find this option but to no success. Please help! P.S. I am new to LTspice, so forgive me for the naivete of my questions. Clarifications on my understanding can be much appreciated. Thanks. |