Electronic Basics #37: What is Impedance? (AC Resistance?)

In this episode of Electronic Basics I will tell you all about the concept of Impedance. That means I will demonstrate how capacitors and inductors act as "resistors" with an AC voltage and thus change the magnitude and phase of the current flow. Afterwards I will show you a simple impedance calculation with a resistor and capacitor in series. And at the end you will understand that the Impedance is an important concept when it comes to AC circuits with R,L,C components.

Thanks to JLCPCB for sponsoring this video

Music:
2011 Lookalike by Bartlebeats

[shraiwi]

*_Yeah, im gonna have to watch this one a few more times..._*

[northshorepx]

Ahh Impedance - this was what made complex number theory come to life for me! This is was sort of where I started to realise why electronics and maths go so well together, and how electronics were just maths made out of materials, and how electronic functions could be analysed and have further functionality inferred through mathematical manipulation - and vice versa! Thanks for such a great into!!!

[shayanirenberg]

Greatscott explained this better than any college professor :)

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[akshaymomaya]

Well, to be honest, I have learnt a lot more than complex circuits in my life realted to AC inductance, reactance etc, but I never realized why one would want to learn that, professors in college didn't ever teach practical circuits or told why you want to use this equations, now watching this video, my theory lectures makes sense!! Thank you Great Scott!

[theknifesedge]

Thank you so much GS! Impedance is always a confusing topic, but you hit the nail right on the head!

[justinvzu]

It took me two years, but I finally sorta understand what Impedance is, and why it's important for my guitar Amp.

[taldmd]

Phasors, bring me back memories from the first circuit analysis classes from college. For a newbie, transient analysis and sinusoidal steady state might be overwhelming... just wait for the rest of the degree, and this will become a piece of cake.

[ryccoh]

I think you could have explained why inductance causes impedance better. An inductor creates a strong magnetic field which works against the intended current flow because it ultimately causes back EMF said simply a voltage in the opposite direction. However only a changing magnetic field has this effect, not a constant one. This is why GreatScott says in the video that it is not an issue in DC circuits in order to not confuse people. The effect of back EMF does show in DC circuit but only when first energizing the circuit, what happens is that the current rises slowly over time to it's maximum value. Once it has reached that maximum value then the inductor no longer has an effect on the DC circuit. Moving to AC, current reverses over and over at very short time intervals, therefore usually at high frequencies the rise time of the current that we talked about earlier is longer than the time for reversal of current which ultimately places a limit to how high the current rises at it's peaks in the sine curve, this has the effect of a current limiter like resistance but through a different means, known as reactive inductance which is an ingredient in the overall impedance of the circuit.

[nlagas]

This is how it shall be taught at school ! You explained in minutes more than in weeks. You shall get a medal !

[TDG]

I was supposed to know all this stuff last year and I never knew you could draw the complex and real impedances in a graph and get the phase angle and magnitude that way.

[BharatMohanty]

Finally basic electronic s after a long time.... :-)

[real]

I started watching your videos when I was in 9th standard but didn't understand anything but now as i studied mathematics in heigher classes I'm happy to say that I'm understanding everything and now I'm loving mathematics even more

[MultiWirth]

That´s what we have done in 4 weeks of education of electrician for industrial engineering.
Great job explaining it in just 10 minutes!

[KiatHuang]

Wasn't expecting a maths lesson thrown in for free as well! Impressed it was done unapologetically. This man does not treat his audience as if some are dummies - he just gives the facts at gets on with it. Bravo!

[baconpancakes]

Your explanation and animation is 𝙥𝙚𝙧𝙛𝙚𝙘𝙩

[flomojou]

Great work! I’ve been working with electronics most of my life and while I understood what effect capacitors and inductors had, and how to use them, I was still unsure about impedance, how it was calculated. Thanks for helping us all to understand a little bit more about the more complex relationships between AC power, inductance, and capacitance.

[fd]

This explained it perfectly. Years I've not really thought about it and when I did it confused me a little. Your handwriting is excellent too. Wish I could write like that!

[ElectricalisEasy]

Your style of presentation is very effective...right on point..nothing more nothing less..

[Saccy_]

This is exactly what I needed!!! I was working on a project and since I'm a newb I had no clue about impedance for my pull down resistor value, you saved me a ton of research, thank you GreatScott!

[jonclarke]

Yep. This is why I preferred DC Electronics Class at university. Going from Polar to Rectangular and back again was a pain!! But the video was very nostalgic for me. Thanks Great Scott!!