LTspice Lesson 5: How to simulate impedances?

[Kashif]

All,

Continuing my lessons: LTspice Lesson 5: How to simulate impedances?

LTspice Lesson 5: How to simulate impedances?
Posted on July 11, 2020 by ExploreSilicon
Commands covered: .ac .meas

What is impedance? Impedance is simply defined as voltage divided by current (Z = V/I). This definition of impedance applies to both in the time domain or the frequency domain. In the frequency domain it’s really the magnitude and phase of sine wave that are used for voltage and current. The math involve complex algebra, but doable for simple circuits. This is really the basis to do simulation in LTspice.

V = Z * I

Choose I=1A constant current source, then V = Z. We can measure voltage easily in LTspice that essentially equal to impedance. Let’s illustrate how this work in LTspice using basic passive components.



Figure 1: Simulation circuit for a resistor, a capacitor and an inductor

continue here...

https://iexploresiliconvalley.com/2020/07/11/ltspice-lesson-5-how-to-simulate-impedances/

Enjoy and feel free to comment and provide any suggestion here.



Link to all the lessons so far:
https://iexploresiliconvalley.com/category/ltspice-for-ee-students/

[Hawkansson]

Dear Kashif, I came here on a somewhat different, but related question. I am looking to simulate a measured impedance in ltspice. Do you know if there is any component in ltspice that allows  custom impedance data, like "Freq, Mag, Phase" csv format for instance?

Best regards,
David

[Kashif]

Hi David,

Sorry missed your message, do you mean how to import measured impedance data in CSV format into LTspice? If that is case, I am not aware of easy way of doing it. If purpose is to do some comparison between measurement and simulation, I would export LTspice simulation data and do a comparison in some other tools like Python or Matlab. Hope this help!

BR,
Kashif