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Questions tagged [modeling]

This tag covers finding models for electrical and electronic components and circuits

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3 answers
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How do I analyze an emitter follower with a capacitive load?

How do I analyze an emitter follower with a capacitor load? At 7 MHz, a 1 nF capacitor has impedance of 22 Ω. A simple emitter follower with a 22 Ω Re is easy to analyze: However, replace that ...
SRobertJames's user avatar
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1 vote
0 answers
16 views

Cannot get correct output in PSpice with the Buck Converter PSpice Transient Model from TI

I obtained the LM76005-Q1 transient model from the Texas Instrument website and imported it to PSpice. The website also provides a Design Calculator software, so I basically use it to determine other ...
Duc Anh Vu Trinh's user avatar
0 votes
1 answer
31 views

Diffusion Current for Non-Linear Charge Carrier Configurations

Diffusion current in a MOSFET device can be calculated using Fick's Law per \$J=-qD\frac{d \rho}{dx}\$. It is often taken that the charge carrier configuration (\$\rho\$) across the MOSFET channel is ...
Schoppe's user avatar
0 votes
0 answers
33 views

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 ...
Samiha Tahsin's user avatar
1 vote
2 answers
168 views

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 ...
LevGor's user avatar
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0 votes
0 answers
39 views

How can a power converter small signal model predict transient behaviour during a load step which is a large signal disturbance?

I see small signal model being used to predict the Overshoot/Undershoot of output voltage due to a load step. How do we justify this approach, since the basic assumption of small signal modelling is ...
Dynamic_equilibrium's user avatar
5 votes
2 answers
520 views

LTspice: weird behavior of simple RC circuit

I try to model a simple RC circuit with input of 2 A DC and I get an out voltage (Vc) of 2 TV. I am not sure what I am doing wrong. EDIT: This is for MacOS
user510's user avatar
  • 235
0 votes
1 answer
81 views

Determining the current carrying capability of a hollow cylinder

How can one analyze, to some approximation, the current-carrying capability of a hollow cylinder with a diameter of 3 inches and a length of 6 inches, made from 100 μm thick copper with a resistance ...
user510's user avatar
  • 235
1 vote
1 answer
95 views

Electrical modeling of multilayer structure

If I have a construction of layers wherein the topmost layer is conductive, followed by two different insulation materials in between, and a bottom structural layer that is a partially conductive ...
user510's user avatar
  • 235
1 vote
0 answers
27 views

Battery Pack discharge behaviour

i want to simulate the discharging behaviour of several battery packs/modules connected in series to simulate a discharge machine for a recycling facility. I wanted to simulate possible current/...
ElectricalStudent's user avatar
2 votes
0 answers
51 views

How to learn about memristors as a circuit designer? [closed]

I'm trying to learn about memristors to play with it in circuit design. I think it might be more intuitive to do tests and measurements rather than reading maths formulas. The problem is that I don't ...
Jack Black's user avatar
1 vote
1 answer
85 views

Thermodynamics of a simple electrical conductor

I derived an expression for the time constant of the temperature of an electrical conductor and was looking for some constructive feedback. Initially there is no current flowing through the conductor ...
user50655's user avatar
2 votes
1 answer
222 views

An AC motor is a transformer? How?

motivation: A guy I worked with years ago (~2015) who is an EE said that "an electric motor was just another form of a transformer". I'm not an EE, so I didn't do things with transformers. ...
EngrStudent's user avatar
1 vote
2 answers
300 views

What are techniques to fix/compensate parasitic effects that occur at very high frequencies in passive electronic components on circuit level?

There are of course equivalent circuit models for modeling practical passive components using idealized elementary circuit models that reflect the parasitic effects that occur at high frequencies , ...
AbdAllah Talaat's user avatar
1 vote
1 answer
157 views

Piezo sensor at resonance - equivalent model

piezo materials are commonly modelled with the BVD model When the piezo is used as a sensor, they are commonly modelled as a current source in parallel with a capacitor because à external force ...
nohu42's user avatar
  • 31
3 votes
2 answers
139 views

Is there a way to take this buck diagram and reduce it to an AC transfer function?

I am semi-dangerous with switchers but I've never really delved into the innards of them so I'd like to ask about this TPS23750 diagram. I would like to develop a model of this feedback loop of a buck ...
Voltage Spike's user avatar
  • 84.6k
3 votes
0 answers
41 views

What kind of model can be used to simulate over- and under voltage in a Li-Battery pack?

So far I have not much experience with modeling in the field of lithium-ion cells or batteries except equivalent circuit models (ecm)-models which I've implemented and used for simulations in Matlab/...
Medi1Saif's user avatar
  • 185
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0 answers
187 views

Modelling of MOSFET

I was wondering if there's a way of creating a simple MOSFET model that predicts how the following circuit behaves when voltage source V is varied. As I understand it, if MOSFET M1 is in the ...
Andrew Lees's user avatar
4 votes
2 answers
314 views

Improving Modeling of Thermal Noise in Radio Antennae

Background I'm attempting to write a physics simulation code, one portion of which involves the simulation of the voltage observed at a set of \$N\$ radio antennae immersed in some medium due to ...
MomentumEigenstate's user avatar
0 votes
0 answers
93 views

Distributed-element model of a series-RC transmission line

The equations for modelling most transmission lines can be based off the telegrapher's equations but the ones I found only account for parallel resistance with the capacitance, but I would like to ...
TWiz's user avatar
  • 373
2 votes
1 answer
123 views

JFET mismatch between mathematical model and SPICE

As a sequel of this question, I built a mathematical model for the Id current of the following (same) JFET circuit: For a simplified model, I took LAMBDA=0 and set ...
edwillys's user avatar
0 votes
0 answers
52 views

Build simple LTspice MOSFET model for textbook examples

I am trying to build a simple MOSFET model (very simple, no parasitic capacitance, gate leakage, ohmic contact...) using LTspice to simulate school textbook example, but I don't know how to switch ...
Willis Lin's user avatar
2 votes
1 answer
580 views

Why does the frequency deviation of a FM wave have different definitions?

Source 1 defines the modulation index in the expression for FM as follows: As per the expression for frequency modulated wave, isn't the frequency deviation same as Modulation index 'M'? "The ...
Dynamic_equilibrium's user avatar
9 votes
1 answer
406 views

Why are these commercial MESFET model parameters unrecognized by LTspice?

I am trying to add a commercial GaAs FET model (ATF34143) in LTSpice XVII for simulation. The model is provided on this website (http://www.hp.woodshot.com/hprfhelp/design/SPICE/fets.htm#ATF34). ...
Matteo Aluffi's user avatar
0 votes
0 answers
19 views

What are NMOS level 1 CV equation and its main parameters?

I was asked to perform MOSFET CV modeling. I looked through some papers, but I still can't clarify what the CV model equation for a level-1 NMOS is, and I am also not sure what its main parameters are ...
Ko Stuart's user avatar
1 vote
1 answer
505 views

Equation for diode saturation current in photovoltaic cell model

I've been looking for mathematical models for photovoltaic cells. Most of the references I've found use the following circuit to the model the behavior: Particularly, the diode current is modeled ...
puq_87's user avatar
  • 69
3 votes
1 answer
480 views

Can I model a diode with higher than usual junction voltage in LTspice using the "Eg" and "Vj" parameters?

I want to model a GaN transistor and include a diode to simulate its reverse conduction above ~2 V with an adjusted diode using the following model statement: ...
tobalt's user avatar
  • 22.4k
1 vote
2 answers
267 views

Forward diode depletion capacitance formula

Does anybody know the forward depletion capacitance formulas for diodes in spice models? Background: The capacitance of a diode in reverse direction usually is dominated by the depletion (or junction) ...
drahnoel's user avatar
  • 143
1 vote
1 answer
119 views

What is the type of material used for the casing of semiconductors?

I am trying to build some thermal models for leaded and surface-mount diodes and transistors. Below is a picture of the TO-220 outline I got from the internet. What kind of material is the black part ...
FlakR's user avatar
  • 749
1 vote
1 answer
130 views

Error in modelling a photovoltaic panel using Plecs software. What could be wrong?

I have a work titled MPPT P and O algorithm with a buck-boost converter. The software I am to use is Plecs. First I wanted to design a photovoltaic model in Plecs. I tried to follow an example I got ...
Awesome's user avatar
  • 11
-6 votes
1 answer
529 views

Antenna model by chatGPT AI - correct or not? [closed]

I asked chatGPT about a basic simplified model of an antenna according to my conception of it (pasted is the most relevant part of two separate answers). It would look like this: ChatGPT AI ...
ee_student's user avatar
1 vote
4 answers
131 views

Does the method of Similitude apply in electronics and electrical engineering?

In engineering, there is a theory called Similitude, which describes how models and testing conditions must be correctly scaled in order to behave correctly and represent the real thing. The reason ...
My Other Head's user avatar
0 votes
0 answers
44 views

How to include dead times into the model of the three-phase voltage source inverter?

I have been developing a Scilab model of the three-phase voltage source inverter. I have started with the idealized model where I suppose that in each of the inverter leg one transistor can be turned ...
Steve's user avatar
  • 1,113
1 vote
1 answer
332 views

Question about the Verilog-A implementation of a VCO

I am learning verilog-A to model analog circuits. One of the examples given in the book is that of a voltage-controlled oscillator (VCO). The book says the following about how the VCO can be modelled (...
Leonhard Euler's user avatar
0 votes
0 answers
52 views

MNA matrix of a vacuum tube

I've been working on a project involving a digital model of a vacuum tube. We're currently experimenting with a Wave Digital Filter approach. Now I've been reading Kurt Wegner's fascinating work and I ...
João Vaz's user avatar
3 votes
1 answer
123 views

What happens to reflections when the distance between a capacitors plates is electrically long?

I understand what happens when a transmission line is terminated with a capacitor but what about when the distance between the plates becomes electrically long? For PCB mounted capacitors I know this ...
Edwin Shepherd's user avatar
1 vote
1 answer
710 views

How to model reverse recovery diode in LTSpice?

I wanted to update this subject as LTspice has evolved from this post: How does LTSpice model reverse recovery time? To sum up the above post answered by Ste Kulov: As Ste Kulov said, LTspice allows ...
Jess's user avatar
  • 2,458
1 vote
1 answer
692 views

What is the meaning of a negative capacitance? - Cadence Virtuoso

What is the meaning of a negative capacitance in cadence virtuoso? Here in the following image, I just want to find the capacitance of transistors using "print-->DC operating point". Can ...
mohammad rezza's user avatar
1 vote
1 answer
206 views

What is the meaning of "a" and "z" in capacitor value - Cadence Virtuoso

What is the meaning of "a" and "z" in capacitor value? Here is the image: I think "a" is angstrom, But I am not sure about it.
mohammad rezza's user avatar
1 vote
1 answer
269 views

Definition of small-signal capacitances calculated by Sentaurus TCAD Mixed-Mode/AC Analysis

I'm currently working on a capacitance model which will be part of a greater compact model for a planar RFET. I use Sentaurus TCAD to generate capacitance data, which I use to understand the ...
zraibra's user avatar
  • 11
2 votes
1 answer
80 views

Obtaining the State Space representation of a microgrid by combining the state space models of the subsystems

I am trying to obtain the state space model of the DC microgrid shown in the figure. It is made of three converters connected in parallel. Each one is modeled with a voltage source that outputs the ...
FernandoPT's user avatar
1 vote
0 answers
42 views

How can I find critical field in tsmc65 transistor parameter?

How can I find critical field in tsmc65 transistor parameters? Critical field is the field which electron velocity in transistor go into the saturation region.
mohammad rezza's user avatar
1 vote
0 answers
35 views

Mapping geometric to electric parameters for a PMSM machine

I am looking at a PMSM machine described by the following equations: $$\frac{di_d}{dt} = \frac{\omega_e L_q}{L_d}i_q - \frac{R_s}{L_d}i_d + \frac{u_d}{L_d}$$ $$\frac{di_q}{dt} = -\frac{\omega_e (...
Josef's user avatar
  • 11
1 vote
0 answers
1k views

How to find (mobility*Cox) and Vth

How to find "mobility*Cox" and "threshold voltage" of NMOS in cadence virtuoso? I have performed DC analysis in schematic environment and using NMOS model parameters, I tried to ...
mohammad rezza's user avatar
1 vote
1 answer
54 views

Modeling first-order dynamics of a switching converter

I have created a simple, first-order model of a switching regulator in steady state (it's basically a transformer with a loss element). Its only parameters are desired output voltage \$V_o\$ and ...
divB's user avatar
  • 1,326
1 vote
1 answer
293 views

LTspice, modeling line driver with propagation delay (LH0063)

Question I'm trying to make a component model for the LH0063 single ended line driver in LTspice... The propagation delay is the dominant parameter for the frequency response but I'm having a hard ...
Tony's user avatar
  • 683
0 votes
1 answer
104 views

Question regarding state-space modeling of a simple electrical circuit

Consider the circuit in the picture, where we have a voltage source (input) \$V(t)\$ and a capacitor \$C\$. The goal is to derive a state-space model of this circuit. The circuit satisfies the ...
Shi James's user avatar
  • 101
1 vote
0 answers
527 views

MOSFET model in LTspice with Miller Theorem

I want to make a MOSFET model in LTspice with a current source and the input capacities to see what happens in the switching process. I'm not 100% sure but I think it works. Below is the formula I ...
Daniel Müller's user avatar
1 vote
1 answer
94 views

Is the "\$\small o\$" in \$r_o\$ short for output or number 0?

You usually see ro in the small-signal models of BJTs or MOSFETs like this. I'm curious if the "o" there is short for "output" or just the number zero? I think I saw people reading ...
internet's user avatar
  • 698
2 votes
1 answer
292 views

APD (Avalanche Photodiode) Active Quenching Circuit (AQC) Waveforms & Circuit Behavior

I am reading a paper tiled Avalanche photodiodes and quenching circuits for single-photon detection The paper presents an Active Quenching Circuit schematic, briefly describes its operation, and shows ...
Cole Fehr's user avatar

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