LTSpice is a version of SPICE from Linear Technology

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Why doesn't LTSpice predict this op-amp oscillation?

I'm developing a circuit to act as an electronic load for bench testing power supplies. An earlier question about how to test this circuit received several very useful answers and can be found here: ...
2
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2answers
46 views

Parameterizing diode value in SPICE

I have a bunch of diodes of the same type on a schematic in LTSpice. How do I parameterize the diode's type (Value) so that I can change it in one place and it would change it for them all? The ...
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1answer
40 views

This circuit has floating nodes in LT Spice?

This is the circuit I'm working on. This circuit probably doesn't work as intended to begin with, but that's not the point. LT Spice keeps complaining that it doesn't have a reference to ground. I ...
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32 views

LT Spice and inductors parallel to AC voltage sources?

This is a circuit I designed in LT Spice. There is no transformer component in LT Spice so I specified L1 and L2 as magnetically coupled with K L1 L2 1 when I try ...
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1answer
22 views

hspice to ltspice subcircuit

I am a novice with LTSpice, and I am attempting to use an HSpice model from Analog Devices. The component is a comparator (ADCMP601). Unfortunately it appears that there is only an HSpice model, ...
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1answer
20 views

Reverse breakdown voltage setting for the diodes in a solar cell model in SPICE

I want to simulate the reverse breakdown behavior of a two diode model solar cell in SPICE. The diodes configurations without considering the breakdown voltage are as below: ...
2
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2answers
55 views

When using nodal analysis of a circuit involving CCCS, how do you know which currents are entering and which are leaving?

I am trying to solve the following circuit: I believe the answer I'm getting for \$i_b\$ is wrong because I put it into LTSpice and I'm getting that \$i_b = -3.63636\$ This is my LTSpice diagram: ...
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0answers
19 views

External call from LTspice

I'm currently doing some designs in LTspice, and uses the measure statement for reading out a lot of data from the design. The log file though is not the best for overview of the data. The idea was ...
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1answer
31 views

Help in plugging equation in arbritrary current source LTSpice

I cannot plug in the following equation and parameters in arbitrary current source. Any help would very appreciated. ltspice cannot read my parameters..
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1answer
47 views

Stuck in simulation in LTSpice. ESD Generator

I am trying to simulate an ESD Generator equivalent circuit. My schematic is attached below. I am not getting any voltage. I am guessing there is something I am missing. But cannot think of one. ...
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2answers
52 views

How to model a repeating sinc pulse in LTSPICE?

I'm looking to model a repeating sinc pulse in LTSPICE, however I can only get it to fire once. I'm looking to delay it by x many ms, and trigger the pulse the again. Is this possible with LTSPICE ?
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48 views

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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1answer
48 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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0answers
13 views

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 ...
0
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1answer
19 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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0answers
25 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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1answer
56 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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0answers
22 views

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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0answers
58 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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2answers
73 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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0answers
53 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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1answer
37 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 ...
3
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2answers
87 views

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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1answer
76 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? ...
2
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1answer
118 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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0answers
61 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 ...
2
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1answer
150 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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58 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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2answers
52 views

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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1answer
53 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 ...
0
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1answer
238 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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103 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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61 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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0answers
29 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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41 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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1answer
119 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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1answer
145 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 ...
0
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1answer
96 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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1answer
75 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: ...
3
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1answer
124 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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1answer
221 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 ...
0
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1answer
425 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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167 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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2answers
356 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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1answer
172 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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1answer
112 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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2answers
118 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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1answer
125 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 ...