LTSpice is a version of SPICE from Linear Technology

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How do I model an EFT Surge wave equation on voltage source with LTSpice?

I am trying to put the following equation onto my voltage source on LTSpice to get the same waveform. The waveforms and equations are attached
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30 views

How do I model an over voltage spike on LTSpice? Any circuit example

I am doing project, I am trying to simulate an overvoltage/under voltage protection controller on LTSpice. How do I create overvoltage/unudervoltage on a source? For example a transient voltage spike? ...
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Simulate two-port networks in spice

I've been trying to simulate a circuit that includes a two-port network. While I was able to solve my problem using the T-model, I'm curious, how could I simulate a non reciprocal two-port network? I ...
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17 views

Spice Simulation of EMI in Long Parallel Wires?

I was thinking about using an external power supply for multiple pieces of analog audio gear. But it occurs to me that even if I use separate grounds for power and signal, because the wires would run ...
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19 views

ltspice with large transistor array takes long time to solve

I have been working on a project to create several of the same T Flip-Flops with different components in LTSpice. The first uses the built in dflop object from LTSpice and the xor. I then moved to ...
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51 views

Help with Amplifier Circuit

How can I analyze this differential amplifier circuit? I need to find the differential gain, the common mode gain and the CMRR (common mode rejection ratio). And is the schematic okay? The amplitude ...
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Referencing DC Operating Points When Plotting Expressions in LTspice

I'm new to SPICE, and I have a question about SPICE commands and references. I've been using LTspice to design a multistage amplifier, and I am interested in plotting out the outputs of each stage, ...
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51 views

LTSpice AD736 simulation problem

I'm trying to simulate some circuit with AD736 (RMS to DC converter). Datasheet: http://www.analog.com/media/en/technical-documentation/data-sheets/AD736.pdf You can check my attached schematic - ...
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58 views

Problem with simulating LC filter with N channel MOSFET used for PWM

I'm trying to simulate an LC filter for a PWM output and I'm having problems with MOSFET used for controlling the voltage. I'm using LTSpice for simulation. When I filter the PWM output directly, it ...
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48 views

syntax error function if() requires exactly 3 arguments in ltspice what is the error

syntax error function if() requires exactly 3 arguments in Lt spice what is the error i am using the following net list for my sub circuit ...
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35 views

Help with LTSpice!

Im simulating a circuit for my electronics lab and was wondering how can I put a voltage at the end of a wire like in the picture?
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30 views

LTSpice Measurement on Plot

I am modeling different circuits in LTSpice and I cannot for the life of me find ways to annotate the plots with measurements. How can I perform simple measurements such as measuring 3dB points, max ...
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Is there a database on internet for LTspice models?

LTSpice doesn't have many components as default. One has to download the spesific model component and integrate it. Is there a website where I can look for it?
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67 views

How do I model a charge source in SPICE?

I would like to model a force sensor based on a piezoelectric crystal that generates 10pC/N and has a static capacitance of 20pF in LTSpice for simulation purposes. How can I do this?
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29 views

TABLE to .param TABLE

Until now I use TABLE parameters only directly in a Symbol. This is particular for long tables not easily readable. How can I do this over an indirection like shown right hand in the image? ...
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108 views

power supply oscillates when loaded with instrumentation amp

I've been working on an instrumentation amplifier for a PWL ECG signal in LTSPICE. It should be able to filter out the common mode noise. I Also need to design a power supply. Both the power supply ...
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51 views

Convergence problem in pspice but not in ltspice

I am trying to simulate a circuit in LTSPICE and it simulates without any convergence problems. However when I copy the netlist into pspice and try it simulate it I get strange results. It keeps ...
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91 views

LTspice: Vary a capacitor's value over time

I want to vary a capacitor's value over time. A previous question (LTspice: Vary a resistor's value over time) asked how to vary a resistor's value over time. One of the answers was to use a ...
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44 views

modeling AC resistance proximity and skin effect using LTSPICE

I'm designing an air-core loop receiving antenna from <1Hz - 50kHz. Is there a way to approximately model the skin/proximity effect using lumped circuit parameters in SPICE software? I think you ...
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When I run the schemetic in LTSPICE,waves don't change direction.Why aren't waves changing direction here?

What pulse should I set to produce a waveform like in the graph?
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51 views

Why isn't current through D2 0 in LTSPICE?

The current through d2 should b zero as it is reverse biased. Why dosen't ltspice software show zero current? - If I am doing somethin wrong then kindly make correction and tell me what to do to ...
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215 views

AC/DC wall adaptor as LTSpice Analog behavior model (ABM)

Suppose a circuit shuld be supplied ( in real life ) from a wall mount AC/DC adaptor. The adaptor has a nominal voltage of 12VDC 500mA. With no load the adapter puts out 21.6V. After some measurement ...
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76 views

Help Converting a PSPICE MOSFET .LIB to an LTSPICE .SUB

I am designing a buck-boost regulator for a course at school and I would like to use the OnSemi ntk3139p PMOS transistor. OnSemi provides a few spice models for this part and I am getting stuck ...
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51 views

LTSpice parameter sweep of multiple values

I have designed a boost converter for my power electronics class in LTSpice. The thing works just fine, now all I have to do it fiddle with the component values and frequency to describe the trends I ...
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28 views

Simulation of ic1 Bel 1895 in LT spice

I am doing an electronics project on condenser mic audio amplifier. And for this I want to first simulate the circuit in lt spice.But I am not getting how to simulate ic1 bel 1895 on lt spice? Can ...
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40 views

Power feeder current and LTSpice simulation

I'm trying to develop a power feeder as already state in question Power feeder scheme adaptation. I have done some adjustments, now my circuit is The voltage regulator is an LM317. Since I have to ...
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104 views

LTspice MOSFET width sweep

I am trying to simulate the transfer characteristics of a CMOS inverter using LTspice. I want to sweep the MOSFET width and length and observe the effects on rise and fall times of the CMOS inverter. ...
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121 views

Where to get PSPICE models of ceramic resonators?

I wish to design and simulate IF filters using ceramic resonators and crystal oscillators in OrCAD Capture or LT SPICE. The default libraries don't have any ceramics, so anyone know where to download ...
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72 views

How to run new .meas commands without having to rerun the whole ltspice simulation?

I am trying to analyze a circuits properties over a certain range of component values, e.g. a PWM circuit for various settings of the control pot. For this I create a bunch of ...
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66 views

DC Motor inertia voltage drop

following a tutorial on the web I created in LTSpice a DC motor model, but I have a question about the results, the model is: and this is the spice netlist: ...
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119 views

LTSpice showing negative transistor power

I'm using LTSpice to model a LC oscillator, driven by a NPN transistor. When I used the power calculating function on the transistor, LTSpice indicated that during part of the cycle the power ...
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166 views

Calculation in LTspice “never” finishes

I'm currently using LTspice, and I have a problem with it "never" finishing calculating a certain circuit. When I say "never", I mean that it's still calculating an hour after it stated, even though ...
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344 views

How to calculate a circuits efficiency with the help of LTspice

Note that this is not a question for circuit critique (and lots of things could be said about this circuit) but this circuit is only the base for the discussion of further points. Here it is (an ...
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150 views

LTSpice missing an SSR Component?

I want to simulate some circuits with SSR component but LTSpice does not provide this. From Eagle and KiCad I learned I can create my own component diagram. I'm not sure if I can do this also with a ...
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305 views

IR2110 LTspice simulation weird behaviour

I am obtaining weird voltage behaviour at the gate of my high side mosfet controlled by IR2110 which is controlled by PWM. PWM configuration: Vinitial = 0 Von = 5v Tdelay = 0 Trise = 7u Tfall = 7u ...
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162 views

How to plot the frequency response of transconductance of BJT with LTSpice

I need to plot the frequency response of the transconductance of this circuit in the picture with LTSpice but I don't know how. Can you please help me urgently how should I do it? Thanks
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91 views

How to plot sliding average in ltspice?

I would like to plot a sliding average of some voltages and currents. Ideally I would just add a new trace with some expression, but all expressions that I found so far only operate on single values. ...
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115 views

Problem simulating a fixed transconductor with LTSpice

I am simulating a fixed transconductor circuit with LTSpice. When I apply \$1\$V for input voltage, (for DC Sweep) the voltage of collector of \$Q_1\$ has good amplitude (\$30\$mV to \$330\$mV) while ...
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107 views

Add permanent component in LTSpice from asc and asy

I'm trying to add a new permanent component (ULN2803) to LTSpice, having asc and asy files. I have read some tutorials in the web but focused on .lib and .sub files. How can I add the component from ...
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169 views

How reliable or trustworthy are LTSPICE demo circuits?

I'm looking at a few switching power supplies and one of the demo .asc files for the particular controller I was looking at really seems to fit my requirements. Can I use their schematics in designs ...
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848 views

Parts tolerance simulations in ltspice

I just recently found this tutorial (and various other places mentioning a similar technique) when trying to evaluate how one of my circuits behaves when using real world components with real world ...
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94 views

Inverse Nyquist Plot (damping factor) in LTSpice possible?

Looking forward to plot inverse Nyquist A11 (damping factor). So the inverse of the transfer function. Is it possible with LTSpice? Ps: Transfer 1/A11 Nyquists are no problem.
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How is Waveform Compression used in LTSpice to determine Timestep?

The LTspice wiki says (and I believe this is basically copy pasted from the offical documentation): Syntax: ...
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149 views

LTspice: Noise simulation AND AC analysis in one plot

Is it possible to run a noise simulation and an AC simulation independently from one another and display the results in the same plot? Or better, is there a way to determine the SNR in one single ...
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59 views

asymmetric supply voltage for an OP AMP

I'm trying to amplify a signal with the bandwith of 500Hz - 10Khz, to do that I'm the circuit in LTspice using an asymmetric supply for the OP : the resistance R5 is just to keep things ...
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160 views

Stepped Sine Wave in Spice

I'm interested in simulating a circuit using a stepped sine wave input. I want to sample a sine wave at regular intervals and have the output constant during each interval, making an output that looks ...
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181 views

Are the stock transistor models in LTspice accurate at RF?

Just checking, I'm doing some experimenting of small signal RF design in LTspice.
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90 views

Creating an adjustable output regulator, in LTspice

Firstly, I'm having some trouble with simulating a variable resistor in LTspice.. I am wondering if this can be done? Also, does anyone have any advice on how to theoretically analyse this circuit? I ...
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633 views

How to use .step param with more than two parameters in LTSpiceIV

I need to do three transient simulations with different values of certain resistors (conveniently called R1 and R2) in each. What I mean to do exactly is this: Sim. 1: R1 = 1 k\$\Omega\$, R2 = 10 ...
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Designing a Filter

I am trying to design a filter which has the following Bode plot, So according to this site I designed the filter as shown below, As the two cross over frequencies are f1 = 50 Hz and f2 = 200 ...