# Measuring Impedance Virtually

We always enjoy a [FesZ] video and we wonder if the “Z” stands for impedance? That’s the topic of his latest video series: measuring impedance with LTSpice. Of course, he also does his usual thorough job of mapping the virtual world to the real one. You can see the video below.

It is simple enough. Impedance is very similar to resistance. That is to say, we have a ratio of voltage and current. However, since it is an AC quantity, you need a complex number to represent it and there is an associated phase shift.

We learned the mnemonic phrase “ELI the ICE man” to help remember that voltage (E) leads current (I) in inductors (L) and the reverse for capacitance (C). Things get more complex — no pun intended — when you mix capacitors and inductors which requires a vector addition.

Keep in mind that complex numbers can appear as a real and imaginary part — in this case, real resistance and an “imaginary” reactance or you can show a magnitude and a phase angle. Both representations have their uses.

This video is only part one of two, but we are looking forward to the next one. We are big fans of LTSpice, ourselves. We’ve talked about impedance, too, if you want our take on it.

## 9 thoughts on “Measuring Impedance Virtually”

1. roonb says:

I don’t care what engineering persons think but using “Z” in this day and age is pure and simply one big faux pas aimed against people who suffer in central-european conflicts. We should really look for other, less offensive symbols.

I really do come here for the comments.

2. DocP says:

This comment (by roonb) is silly and lacks any semblance of logical reasoning. The follow on proposal to the above will be that we should destroy and replace all engineering, physics and math textbooks that use “z” or “Z” to express complex numbers. How about banning “Z” from the alphabet altogether and using a Greek character, or an arbitrary made-up one to replace it? The use of the letter Z to express impedance, or the use as a variable in any other mathematical equation is in no way being insensitive to people who are suffering as a result of current conflicts.

3. matt says:

I propose Q.

1. cncFriend says:

The Q would like a word with you….

4. qwedsazxcvbnhgf says:

Replacing technical terminology simply because of percieved offensiveness is NEVER right. We still have SPI slave selection lines afterall. Most such fear of offence is perpetrated by those Taking Offence On Behalf Of Others (TOOBOO), others who aren’t actually bothered.

1. Mdl says:

Haha, not anymore we don’t. There are no more slave selection lines, only Chip selection (CS) and even MISO/MOSI is being replaced with CIPO/COPI or PICO/POCI .

2. Nick says:

TOOBOO, i love it. I hope this acronym takes off.

5. Miroslav says:

I hope you are joking. Next you will propose we ban number 3, because that’s very similar to Z in Cyrillic?

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