Questions tagged [ltspice]
Anything related to LTspice. LTspice is a SPICE simulation, schematic capture, and waveform viewer program from Linear Technology. LTspice is freeware with a very liberal license, it is lightweight, and isn't crippled in any way.
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What is this circuit? (FM detector?) - LTspice
I have this circuit from college (almost 15 years ago) that is through-hole components wired together and it picked up the strongest local radio station. I now can't get it to work, so I'm wondering ...
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LTspice Monte Carlo with different model libraries
I'm trying to figure out how to do my first Monte Carlo analysis in LTspice. I have a very simple schematic that includes the SPICE model for PN 74LVC3G17DC (vendor link).
The distribution from the ...
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How to interpret Ids of low-side FET in phase leg configuration?
I am simulating a phase leg configuration as shown below using a GS66508T GaN FET. Does anyone know if the circuit is working correctly according to the current plot?
There is current spike above 30 A....
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LTspice problem - AND gate gives wrong output - please help
I am building an SRAM memory in LTspice. For the input I am using two muxes in column. Inside the muxes I have a problem with one of the AND gates- please see attached picture- the lower and gate is ...
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Questions on piso shift register and simulating in LTspice
After my previous question, I attempted to simulate an 8-bit "parallel in serial out" shift register in LTspice as follows:
The above schematic is not very readable due to its size so below is the ...
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Appropriate models to model magnetic components in LTspice and what are the pros and cons?
I'm looking for appropriate models to model magnetic components, mostly transformers and perhaps for chokes as well, for use in LTspice.
I've heard briefly of some models, like Jiles-Atherton-model (...
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Generating a clear sinusoidal wave through the oscillator to generate the "Ding Dong" sound
I am working on a project to try to recreate a close replica of the "Ding Dong" doorbell sound. I have yet to make the decay. (I would definitely appreciate if you have tips for that.)
I am ...
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How Does This Diode Affect This Circuit? [closed]
I am learning about electrical engineering and have a question about this circuit.
I don't have a very niche question, I'm just wondering how the circuit is affected by the addition of the LED.
You ...
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Effect of coupling factor in flyback converter relative to rectifying diode
I'm simulating a CCM flyback converter on ltspice, and I need some help in understanding the results when I decreased the coupling factor from 1 to 0.96.
When K=1, the voltage appearing across the ...
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Problem Using Resistors in LTSpice
I am new to electrical engineering and I’m having a lot of issues with resistance in LTSpice.
Because I can’t set the current, I am unable to determine how far the voltage will drop.
For example, I ...
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How to simulate this circuit for common mode voltage effect?
Regarding my previous question and this paper, I wanted to simulate the circuit below to see whether it is rejecting common mode voltage as claimed. The paper says that sharing DAC's Vref with non-...
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OPA656 Simulation works on TINA but not on LTspice
As mentioned in the title I use LTspice as my main workflow to simulate circuits. One of my circuits is using an OPA656 amplifier. I attach a picture of a simple schematic I made to test the issue. It ...
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Voltage drop issues in LTspice simulation for buck converter using SW model
I have a LTspice design issue where I encounter the same problem, even when I use other available simulations.
Whenever I increase the load, there is a significant drop in voltage, despite having ...
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LTSpice (mac) How can I display the current in the schematic?
I want to simulate a circuit and display the current directly in the schematic.
However I am only able to display the voltage.
Here you can see an example where someone actually displayed the current ...
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Why do the diodes make a huge difference in an RC sinewave generator circuit?
In the following LTspice simulation of a sine wave generator circuit, it cannot oscillate without D1 and D2, but as long as D1 and D2 are added, (1+R5/R6)=1.5 can also oscillate (as shown in the ...
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OpAmp Offset Null Pins in LTSpice
I'm simulating the following circuit, where the Op Amp is an LM741:
The LM741 is an 8-pin device, and this design calls for using 7 of them. From the datasheet, here are the pin connections:
I have ...
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LM317-N output voltage lower than expected in LTspice Simulation
I am designing a circuit that requires a regulated 1.75 V source. After searching around I found the LM317-N voltage regulator and got it's SPICE model from TI to simulate it within my circuit. The ...
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Cannot get the required simulation waveform of a Quasi-z source inverter using Si mosfet
This is the circuit I'm trying to replicate, with the waveform.
I found it here.
This is my attempt at it, but the waveform does not match.
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How to solve the LTspice error "Questionable use of curly braces in xxx."?
When I set up the following circuit, I ran into a question about the use of braces({})
The following are error messages:
Why can't the first V be recognized by LTspice, or is something else wrong?
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Using a N-channel JFET as a current source
I have used the BF256 (N-channel JFET) many times as a current source, but it is a through hole component and I prefer to use SMD.
I found a few documents on the internet that all list other dynasaurs ...
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Wheatstone bridge and difference op-amp
I use Wheatstone bridge as a dual voltage divider to feed both inverting and non-inverting inputs of differential op-amp:
Theoretically voltage can be calculated using voltage divider expression: Va =...
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Extracting equation/formula of drain current for the circuit model
I have simulated this circuit model in LTspice. Now I want to do an experimental fit for the graph for transient analysis of Id. Can anyone help me solving this circuit for Id? Or give me an ...
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Could not open include file "amplifier.sub"
I don't understand why this file that include my subcircuit can't open be included.
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Increase the size of ltspice error log file contents
In my circuit when I am sweeping many values and total combinations are higher (>2K), only initial values are captured when using .measure command for each combination. I want to increase the ...
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Accuracy when measuring THD with LT Spice for AB Audio Amp
I've designed and built my own AB class audio amplifier circuit. I designed it to have as low THD as possible, using LT Spice to run my simulations with the .four command, so I created a bunch of ...
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Slow simulation speed of a Very High frequency circuit (LTspice)
I've been working on optimizing the simulation time for a larger circuit. Before asking for assistance, I experimented with several approaches:
Adjusting simulation settings, such as altering ...
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Quadruple MOSFET charge pump simulation does not work as expected
Background
Source claims that this MOSFET-based charge pump circuit should work. The schematic looks logical and I was able to reason my way through its expected behaviour. I tried simulating the ...
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Why doesn't my OP Amp comparator work in LTSpice? (AD8665)
When V2 > V1, Vout should output approx. 5.3V. When V2 < V1, Vout should be approx. 0V. But this op amp seems to always output 5.3V regardless what V2 is. What could be going on here? Is this ...
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How do I understand the reason behind the incorrect result in below LTspice simulation?
Shown below is the LTspice simulation for a full bridge rectifier. The simulation shows 'wrong' result for open load condition (Rload =1 GΩ). Ideally it should be same as other 2 cases.
Why is the ...
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I could not manage to use Switch Component in LTspice
There is a circuit to control a pwm signal with a switch in Ltspice. But it does not switch of despite to off mode of controller voltage. Is there anyone to give me some suggestion.
My and gate ...
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OnSemi NCV1076 Ltspice Model Lib
I am trying to desing a SMPS with LTSpice. There is a driver which ı can use in real.
It is NCV1076.
But ı could not find a .Lib Model to use in LTSpice.
There is a simulation model but it is only for ...
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LTspice: SEPIC simulated output voltage does not match known output voltage
I am designing a SEPIC that meets the following criteria:
➢ Vin = 15 V-35 V
➢ Vout = 25 V
➢ Output voltage ripple 1% peak to peak
➢ Switching frequency 100 kHz
➢ Load 10 W-50 W
Calculations have been ...
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What causes this LTspice error message?
LTspice error message:
Voltage source VSS and voltage source VDD are paralleled making an over-defined circuit matrix.
You will need to correct the circuit or add some series resistance.
Paralleled ...
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Building SPICE models of optocouplers
Looking through this answer about the 6N137 optocoupler I wonder where one can get all those paramaters like Is, Rs, N, various internal resistances, etc. that are used to simulate the optocoupler. I ...
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LTspice - RF LPF design insert loss shows -6 dB
I am trying to simulate an LPF in LTspice, but the insertion loss shows up as -6 dB while I expect the value to be close to 0.
Am I setting the simulation up wrong?
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Simulation of high side N-channel MOSFET with Bootstrap in LTspice
The inverter circuit I made from N-channel MOSFETs is given below. I used bootstrap for the high sides. Bootstrap capacitors are C3 and C1.
The gate voltage of the MOSFET is working properly, the ...
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How can I get the value of pole capacitor and zero resistor in LT1575's open_loop ac analyze
I want to ask the LT1575. Is this my circle connection problem? Why the C4, C3,and Rz can not affect the phase margin in open-loop analyze.
Improved image: -
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EFT generator circuit
I am simulating a circuit to model the EN 61000-4-4 waveform for electrical fast transients using LTspice. The idea is to have the generator for some in house testing.
After a lot of back and fourth ...
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How can I draw LC resonant circuit frequency response in LTspice?
I would like to create a frequency response graph of an LC resonant circuit, illustrating the attenuation (in dB) versus frequency.
The generated response seems inaccurate. It begins at 10 MHz and ...
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In LTspice, is there any way I can obtain the frequency response of power converter alone?
I am aware of the following methods. But my intention is to understand the behavior of power converter alone, before adding the controller and feedback loop.
FRA analysis: Provides the open loop ...
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LTspice custom component - error when placing multiple
I'm having issues with a circuit I'm trying to build using analog multiplier AD633.
I downloaded the model from the official site.
I included it in the schematic using the guide provided by LTspice: I ...
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LTspice parameters
I want to know how the .mod/.lib files in Ltspice are created by manufacturers. Let's say we have a Common Mode Choke (CMC). It will have some parameters as per its equivalent model at different freq ...
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How to check for slope of a square wave output in LTspice
I want know if there is a certain formula that needs to be used to get the positive and negative slope of a square wave. Let Vn001 be the indication if its positive and negative? Or can I simply trust ...
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How can I check the slope at a certain point in a graph in LTspice?
Hos can I find the point in an LTspice graph where the slope is -1?
Example:
Is there is a way to find out, or do I just need to guess?
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How are SPICE files created compared to S4P files generated from a VNA?
When measuring impedance versus frequency using the same data in both SPICE and S4P formats, why do I obtain different results?
COMMON MODE IMPEDANCE
Common mode impedance 10514 Ohm at 79.1 MHz
S4P ...
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Positive and Negative Dual Power Supply
I want to build a dual power supply board that works with 12V DC from the power adapter and gives +/-15V at its output. I came across a schematic in LT3094 datasheet on pg 30.
I am trying to simulate ...
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"*" unknown parameter in LTspice simulation
10000 * exp(3000*(1/298.15 - 1/(t+273.15))),
this expression in LTspice showing "*" as an unknown parameter. How to fix this.
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LMG1210 application in LTspice
Could you help me with the driver LMG1210 to work in LTspice. On the TI website there is only Pspice model LMG1210, so I used auto-generation to work with it in LTspice. However, when running the ...
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LTspice: Pass/fail in error log if voltage < constant reference
I am looking for a way to have LTspice report a "Pass" or "Fail" ("1" or "0") in the error log if a measured voltage drops below a preset constant reference ...
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Simulation of transimpedance amplifier in LTspice
I am trying to simulate a circuit that is presented in a research paper by Dr Behzad Razavi. I am using LTspice for the simulation (please see the attached image and netlist for the circuit).
I am ...