New answers tagged ltspice
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Why is step response of an opamp linear/exponential?
Real world op-amps have limitations of the real world.
One such limitation is bandwidth. They do not have infinite bandwidth and it means for a relatively fast step input which has relatively high ...
- 138k
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Why is step response of an opamp linear/exponential?
The LM741 has a slew rate of only 0.5V per us. The TL081 has 20V per us. So the LM741 ist just damn slow :-)
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Why is step response of an opamp linear/exponential?
The LM741 is being slew-rate limited here; op amps have a maximum slew rate, which is the maximum slope at which the output can change. The LM741 has a particularly low one (it's about the worst op ...
- 30.4k
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Error when defining resistance values with parameters
RE2, RE3, RE4 and R4 have a resistance value of R2 which is supposed to be defined somewhere in the simulation.
Define R2 with .param or something else e.g. ...
- 30.5k
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How to plot "voltage drop" across a specific component in LTSpice?
You can also right click and mark a point as a reference and then get voltage from that point to any other.
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Why are the current-voltage characteristics of a bipolar transistor in MATLAB and LTspice different?
Both models - Gummel-Poon as well as Ebers-Moll - do reflect the physics of the BJT which, in fact, is voltage controlled (Shockleys equation): Ic=f(Vbe).
I do not know how your simulation programs (...
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LTSpice PMOS model differs from by scratch implementation
There are two main discrepancies between your MATLAB implementation and what LTspice does.
First, there are two substrate PN junctions that SPICE models in addition to the drain current equations. ...
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Triac Not Triggering in Q3
If you look at the .zip file provided by ST, it includes a .lib (models) and a .olb (symbols)...
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Why are the current-voltage characteristics of a bipolar transistor in MATLAB and LTspice different?
...although both programs use the Ebers-Moll model.
This is the assumption you are making which is causing your problem.
LTspice generally uses the Gummel-Poon model of the BJT. If no Gummel-Poon ...
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LTspice if statement
You could try using a behavioral voltage source (bv). This will allow you to use a formula for the voltage, such as this:
V=5*({R}>5000)
Here I've done this with ...
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Inverting opamp amplifier: frequency response not compatible with LTspice simulation
Looks like you are using a behavioural opamp model. If so, you need to adjust the gain-bandwidth (GBW) of the model to match the GBW of the TL082 which is typically 3 MHz. Depending on the breadboard ...
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Inverting opamp amplifier: frequency response not compatible with LTspice simulation
Well, notice that your transfer function is given by:
$$\mathscr{H}\left(\text{s}\right):=\frac{\displaystyle\text{V}_\text{o}\left(\text{s}\right)}{\displaystyle\text{V}_\text{i}\left(\text{s}\right)}...
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Inverting opamp amplifier: frequency response not compatible with LTspice simulation
The model that you use can make a big difference in the frequency response. I don't see any number for the op-amp in the schematic, which suggests you may be using a generic op-amp model. You should ...
- 19.7k
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How to flip LTspice voltage controlled switch so that it opens at threshold voltage? (versus close)
make Ron=1Meg, Roff=1p, it will work visaversa
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Trouble with filter using Laplace transfer function in LTSpice
The Bessel coefficients from Wikipedia yield a filter with unit group delay, not unit cutoff frequency. It is thus not surprising that you don't get the cutoff frequency you expect.
What is your ...
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Trouble with filter using Laplace transfer function in LTSpice
Save some grief: set \$\omega=1\$
Just save yourself some algebra grief and set \$\omega=1\$ when focused on a particular filter shape (like Bessel.) The filter shape can be moved around freely (at ...
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Trouble with filter using Laplace transfer function in LTSpice
I suppose that the mentioned frequency (f=3.5 kHz) is the desired 3dB-frequency (your requirement), right?
In this case, it is not true that the corresponding w value (2Pi*f) would appear in the ...
- 25.7k
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How to create a PWM source with fixed frequency and decreasing duty cycle (at some interval) in LTspice?
Probably brute-forcing a solution using a PWL source is the quickest way to a solution. It's very useful for weird and/or complex sources. Once you dabble in generating your own PWLs using a ...
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LTSpice (Berkeley Spice) Files. WHERE?
You get the models from either the manufacturer or another party that has modeled the device.
It is possible in LTspice IV to create a new symbol from scratch for a
third-party model but who has the ...
- 78.1k
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How to create a PWM source with fixed frequency and decreasing duty cycle (at some interval) in LTspice?
For an arbitrary stimulus in SPICE I write a program in some other language (I like AWK, you might prefer something else like Python) that writes an output file containing the definition of a PWL ...
- 2,665
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How to create a PWM source with fixed frequency and decreasing duty cycle (at some interval) in LTspice?
I'm not exactly sure what you want to do, but I might have a way to accomplish it that is unproven.
Look at the models for the LTC6993 (there are several with different features. They can do many ...
- 78.1k
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LTSpice (Berkeley Spice) Files. WHERE?
Tracking down and integrating SPICE models into a simulation is usually a bit of an adventure. There are many SPICE dialects and no standard. The model files are often proprietary and cannot legally ...
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UCC25800 PSpice model
From a comment:
Is it possible to decrypt the .lib file for use in LTspice?
Since the Pspice model in the question is from TI, performed a search on the TI forum which gave:
Decrypt PSPICE MODEL of ...
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SNR simulation and "desired output signal"
Audio equipment have nominal output levels. Recorders, amps and mixing devices have also nominal input levels. It's either dBV or dBm to the nominal resistive load. Use that nominal level as your ...
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Non inverting opamp with bias DC
You did nothing wrong.
Just choose the value of your resistors R3 and R4 (My R9 and R10).
Like this ...
- 12k
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How to measure flux in transformer in LTspice?
The flux in the transformer core can be assumed as the integral (over time) of the voltage at the inner winding, divided by the number of its turns. So the expression for the voltage should taking ...
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How to measure flux in transformer in LTspice?
None of them is correct.
flux1 looks more reasonable because flux2 uses unswitched windings as well.
Remember the transformer ...
- 30.5k
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Several base current values on the same graph
You can .dc a current source into the base and plot the collector current:
- 19.7k
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Several base current values on the same graph
In CircuitLab you can Run a DC Sweep with a Second Parameter
simulate this circuit – Schematic created using CircuitLab
You can click on the simulate this circuit link above to enter the ...
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Several base current values on the same graph
If you would like to have in your diagram equally spaced base currents I recommend to use not a voltage source with a resistor at the base but instead a current source which can be stepped through ...
- 25.7k
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Several base current values on the same graph
Use the "STEP PARAM" command:
.step param RX list A B C D E F G
If you change R6's resistance value (1000) to something like ...
- 30.5k
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Vpeak to peak using LTspice
Are you trying to put one voltage on the horizontal axis and another on the vertical axis, like this?
If so, all you need to do is right-click on what is normally the time axis and change the ...
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Unable to get my astable multi-vibrator working in LTspice
Here is one problem: The output of the op-amp is connected to GND.
There may be other problems.
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Understanding optocoupler's operation through simulation
Let's run a sim...
CTR looks very different from the datasheet (non saturated case):
Here's the model from LTSpice
...
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Understanding optocoupler's operation through simulation
The datasheet simply says CTR is 20% minimum and 50% typical. And that is at If=10mA.
Datasheet does not say what is the maximum CTR.
So if simulator result shows 70% CTR, it is within specification, ...
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