I am glad I found you now before it was too late, I got my final exam in 2 days and its all about electromagnetism. I was literally so confused but I have watched all your videos from Magnetic forces on moving charges till inductance. YOU ARE GREAT AND A SAVIOUR! Hopefully I will do great on monday.
Here's what he means when he says "the inductor will try to stop the current from changing". The inductor (as he says) doesn't "try" to do anything. If you've run current through it, you have a certain amount of magnetic flux created by the moving current; when you reduce the current, the magnetic lines reduce, cutting through the metal coil; and when the magnetic lines cut through the metal coil as they shrink they indduce voltage or current going the other way; the shrinking magnetic flux spends its energy by inducing current in the coil; you could say (inaccurately), that the magnetic flux is transforming into current as it shrinks, or rather using its energy as it shrinks to induce current in the wire. So ironically, even as you reduce the current from the power source, you are Creating current going in the opposite direction because you have cut power to the magnetic field, which now shrinks and induces current in the wire while shrinking. So the inductor doesn't "try" to resist current change; it simply creates current going the other way as the magnetic field shrinks when you cut power to the coil.
+Masked Marvyl Thanks, i saw a lot of videos and searched a lot of sites. And as i start to read the comments, i finally found someone who explained it the right way
Hello. You seem to have a good grasp on the material, what sources for studying do you recommend that explain such electrical theory in depth and clearly?
Sorry to burst your bubble but when the magnetic field is shrinking, it NEVER touches the metallic boundary. Use your right hand rule and you will see the shrinking magnetic field approaches the outer part of the solenoid while the internal magnetic field is 'expanding' to the inner wall of the solenoid. ALL videos showing the magnetic field shrinking to the center are ALL false when it shrink according to right hand rule. Think 10 times before you type. Understanding magnetic field, it shrinks approaches the metallic surface but it does not damn shrink to the center. I swear people need to understand WHAT is the geometry of a shrinking magnetic field. By the way, amperage is right-hand rule while voltage is LEFT-hand rule.
By the way, the magnetic field fuses. When you think they 'cut', they don't. A wire is a waveguide. You know what I lazy to say anything. A magnet is a rotating torus with both in and both out at either pole. This is the last thing I will say
The mechanical/electrical sluggishness analogy is an eye opener. I had the assertion that inductance and resistance performed similar functions, but now I understand that inductance simply resists the change in current, while resistance impedes the flow of current. Thanks for sharing your knowledge
i'm watching these videos for basic physics in college. man, your videos have given me the basics that the teachers assume that I understood, though I never took physics in high school. thank you SO much for creating these videos, my friend
At time 8:50 you mention that F=ma is similar to E = -L (di/dt). I notice you described under the F=ma column as: m: mechanical inertia "resistance to change in velocity" mechanical sluggishness A small team of us (elec. engr. /physics types) work with artificial gravity and very early in our work, discovered that gravity is a quenching (elimination) of what you call 'mechanical sluggishness'. The Abraham-Lorentz force describes the recoil and loss of momentum of charged particles that are accelerated. For example, electrons in a radio antenna experience what you call "electrical sluggishness" just as in an inductor. Since objects of matter are just large collections of atoms - and since atoms are collections of charged particles - what you call 'mechanical sluggishness' actually has its roots in the recoil/loss of momentum that is 'suffered' by charged particles, just as a change in current in an inductor is an acceleration of charged particles, leading to what you call 'electrical sluggishness' It's important to recognize the following: 1) when a 'mechanical object' like a car starts to brake, it is accelerating in the opposite direction of its travel 2) when current in an inductor 'slows down' or is reduced, the charged particles experience acceleration in the opposite direction of current flow Acceleration in a gravity field leads to zero 'mechanical sluggishness' - the technical term being 'inertial drag,' or 'loss of momentum' If you accelerate in your car, you feel 'pushed back in the seat' - that is inertial drag. If you accelerate in an artificial gravity field, there is no inertial drag. Recognizing that accelerating charged particles experience 'mechanical or electrical sluggishness' whether they are inside an inductor or a person or car or.... etc. is enlightening. Most of us don't think of our bodies as being a huge collection of charged particles, but there you have it. Thank you for an excellent treatment of inductance. The introduction of the terms "mechanical sluggishness" and "electrical sluggishness" is a huge benefit to people learning the subject because it will give them a qualitative grasp of what's happening at the physical level. Although we tend to rely mostly on mathematical description, the qualitative treatment is valuable for people who are new to this topic.
I know you get many of these sorts of comments, but still, thank you so very much. I'm studying for my University Physics II exam and your videos are extremely helpful in laying out and simplifying these topics. You are a wonderful teacher and I am very grateful to you for sharing.
This video cleared up so much confusion! I was struggling to understand WHY exactly the inductor resisted changes in current. Thanks for the wonderful explanation.
I like your simplicity of explaining! I get confused though when you don't specify the current theory as conventional flow, especially with the basics. We all know only electron (electrons) flow is real, but we persist in pretending protons get out of the nucleus and somehow flow since Ben Franklin's presumption. I love to teach with great videos like yours, but unless you specify conventional flow or conventional current, the students get lost and frustrated at first. I have my students learn it both ways and not fight it or they will fail to be pliable and tolerable learners. Thanks again sir!
In short it is only due to the "physical construction and geometry" of a coil which causes building and collapsing of magnetic field around the coil to induce an internal voltage in the coil (Faradays Law) called the counter emf. This counter emf opposes the supply emf or voltage (ac source or battery) causing the current to lag. Hope that is right?
Kind of sad that this is the last playlist I am gonna watch on your channel. Thank you for uploading these videos. I guess, I am gonna be on my own for the thermodynamic chapters=(
I assume that Lasseviren has taken the current flow in the direction of Electron movement rather than conventional current flow - which confused me a little bit but got the Point.
Hi there . I am always having these two questions . In AC circuit it is said that current always keeps changing it's direction . If so , why we always have the same hot wire ( when testing with pen voltage tester) . Second question : Is there really any kind of movement for electrons in a wire when we apply some voltage ? Thank you so much for your help. I have learned a lot from your videos.
The current changes direction because the voltage in the hot wire becomes negative. I am assuming you are wondering why the neutral doesn't become negative and the hot wire zero. The neutral is always zero in normal conditions. Yes there is electron drift. In AC they just go back and forth.
its the same principle we use in copper ballast of fluorescence tube. As the starter breaks the current flow, the magnetic flux in choke changes into high current which initiates arching inside the tube.
Can you explain how this fact is useful in circuit designs? I sometimes see an inductor used in power charging circuitry & I read that it stores energy to increase the charging voltage from a smaller input voltage to a larger charge voltage, but how can I know what the useful limits are in such a circuit to modify it for whatever purpose that I have?
What happens when the current stops abruptly? Will the current flow keep going as the flux reduces in the direction of "electron flow"? I guess I'm trying to understand why it wants to flow in a certain direction.
I'm confused by the battery analogy. Are you saying when i is increasing the inductor is acting like a load, as if it's charging, storing energy like a battery? But when i is decreasing the inductor dumps energy and acts like a source battery. That's the way I see it from your vid. If the battery is charging the neg. terminal is pointing towards electron flow and when the battery is discharging the neg. terminal is pointing in the same direction as electron flow. Not easy to grasp but thanks.
At 4:30 you say the induced EMF pushes the current to the left. The confusing thing for me is : Does the induced EMF give a +-sign on the left side of the inductor and a -sign on the right side of the conductor? Or is it the reverse?
The induced EMF "tries" to push the current to the left. But the current is going to the right. The induced EMF gives a + sign on the left of the inductor and a negative sign on the right side of the inductor. EMF = -L di/dt. So if the current is growing then di/dt is + and the EMF is - (or is opposing the current). If the current is dimininishing then di/dt is - and the EMF is + (or is encouraging the current).
Think of it like the d is for delta - but the change is very small. So it's like a very small change in current over a very small change in time. Or the instantaneous rate at which the current is changing.
I don't get it. I understand that by Farady's law that the current through the coil will create a magnetic field, and the change in flux will create an emf that counters the direction of the current from the circuit. But after it stabilizes, no more emf. So I feel there's only a one-time emf thing gonig on here. How is this useful?
Hey Pablo, you might have already had your question answered by now, but I thought I would take a crack at it anyways. You are right to think that once the current stabilizes that the emf will disappear. However, this would only happen if the current is not changing over time. For this case, a DC circuit which has a constant current, would not need an inductor unless there are other components changing the flux. However, with AC current, your current is constantly reversing itself over the inductor, producing that needed change. Therefore, DC current is constant = No emf over inductor after a long time. AC current is ever-changing = Constant change in current and therefore an emf is produced for a longer period of time.
After taking more classes on electronics, I've learned more uses for inductors, incase anyone reads this! One certain application for inductors is filters! They can filter out electrical signals of certain frequencies. They can be combined with capacitors in different ways to change the flow of current (open circuit or short circuit) depending on the capacitance of the capacitor!
Pablo P yea true. bcuz when u get radio signals or TV signals. there is signal and no signal signal and no signal. using capacitor or inductor its always signal cuz it is discharging while theres no signal and its clear signal
If inductor opposes changes in current by inducing a voltage opposite to the source voltage, then shouldn`t that induced voltage oppose the source voltage throughout resulting in zero current in the circuit..... why then current still flows in the circuit........ what is driving this current ..... how is the opposition to that current is reflected
Fixed current is irrelevant to magnetic flux ; Please indicate the change in current The subject of magnetism is not simple including the the effect of an IRON as a core and the concept of magnetic saturation. .
Professors suck because they are 100 years old and way too advanced to teach basic physics. RUclips is the best place to learn physics. Thank you lasseviren1.
Maybe I’ve smoked to much of the naughty stuff and drank too much in my young years. Idk but my brain seems kinder fried and would like to run away fast on an open empty field from all this stuff. But I want to be an electrician so I guess I’ll need it (I think). :(
oh no, I dont think it's wise to compare force with electromotive force (towards the end of the video) because they're actually different. EMF is more of a work done to carry a charged particle, and hence, not a force.
This is what I mean when I say that old schoolbooks from 1935 don't mention inductors store energy because they knows that it sludge from one side to the other when you changes the flow .store back then means you can disconnect the inductor and when you need it later you can use it
I am glad I found you now before it was too late, I got my final exam in 2 days and its all about electromagnetism. I was literally so confused but I have watched all your videos from Magnetic forces on moving charges till inductance. YOU ARE GREAT AND A SAVIOUR! Hopefully I will do great on monday.
Good luck on the final!
Here's what he means when he says "the inductor will try to stop the current from changing". The inductor (as he says) doesn't "try" to do anything. If you've run current through it, you have a certain amount of magnetic flux created by the moving current; when you reduce the current, the magnetic lines reduce, cutting through the metal coil; and when the magnetic lines cut through the metal coil as they shrink they indduce voltage or current going the other way; the shrinking magnetic flux spends its energy by inducing current in the coil; you could say (inaccurately), that the magnetic flux is transforming into current as it shrinks, or rather using its energy as it shrinks to induce current in the wire. So ironically, even as you reduce the current from the power source, you are Creating current going in the opposite direction because you have cut power to the magnetic field, which now shrinks and induces current in the wire while shrinking. So the inductor doesn't "try" to resist current change; it simply creates current going the other way as the magnetic field shrinks when you cut power to the coil.
+Masked Marvyl
Thanks, i saw a lot of videos and searched a lot of sites. And as i start to read the comments, i finally found someone who explained it the right way
Hello. You seem to have a good grasp on the material, what sources for studying do you recommend that explain such electrical theory in depth and clearly?
Sorry to burst your bubble but when the magnetic field is shrinking, it NEVER touches the metallic boundary. Use your right hand rule and you will see the shrinking magnetic field approaches the outer part of the solenoid while the internal magnetic field is 'expanding' to the inner wall of the solenoid. ALL videos showing the magnetic field shrinking to the center are ALL false when it shrink according to right hand rule. Think 10 times before you type.
Understanding magnetic field, it shrinks approaches the metallic surface but it does not damn shrink to the center.
I swear people need to understand WHAT is the geometry of a shrinking magnetic field.
By the way, amperage is right-hand rule while voltage is LEFT-hand rule.
By the way, the magnetic field fuses. When you think they 'cut', they don't. A wire is a waveguide. You know what I lazy to say anything. A magnet is a rotating torus with both in and both out at either pole. This is the last thing I will say
The mechanical/electrical sluggishness analogy is an eye opener. I had the assertion that inductance and resistance performed similar functions, but now I understand that inductance simply resists the change in current, while resistance impedes the flow of current. Thanks for sharing your knowledge
i'm watching these videos for basic physics in college. man, your videos have given me the basics that the teachers assume that I understood, though I never took physics in high school. thank you SO much for creating these videos, my friend
I love the correlation at the end. Very nice, thorough and concise inductance intro.
At time 8:50 you mention that F=ma is similar to E = -L (di/dt).
I notice you described under the F=ma column as:
m: mechanical inertia
"resistance to change in velocity"
mechanical sluggishness
A small team of us (elec. engr. /physics types) work with artificial gravity and very early in our work, discovered that gravity is a quenching (elimination) of what you call 'mechanical sluggishness'.
The Abraham-Lorentz force describes the recoil and loss of momentum of charged particles that are accelerated. For example, electrons in a radio antenna experience what you call "electrical sluggishness" just as in an inductor.
Since objects of matter are just large collections of atoms - and since atoms are collections of charged particles - what you call 'mechanical sluggishness' actually has its roots in the recoil/loss of momentum that is 'suffered' by charged particles, just as a change in current in an inductor is an acceleration of charged particles, leading to what you call 'electrical sluggishness'
It's important to recognize the following:
1) when a 'mechanical object' like a car starts to brake, it is accelerating in the opposite direction of its travel
2) when current in an inductor 'slows down' or is reduced, the charged particles experience acceleration in the opposite direction of current flow
Acceleration in a gravity field leads to zero 'mechanical sluggishness' - the technical term being 'inertial drag,' or 'loss of momentum'
If you accelerate in your car, you feel 'pushed back in the seat' - that is inertial drag.
If you accelerate in an artificial gravity field, there is no inertial drag.
Recognizing that accelerating charged particles experience 'mechanical or electrical sluggishness' whether they are inside an inductor or a person or car or.... etc. is enlightening. Most of us don't think of our bodies as being a huge collection of charged particles, but there you have it.
Thank you for an excellent treatment of inductance. The introduction of the terms "mechanical sluggishness" and "electrical sluggishness" is a huge benefit to people learning the subject because it will give them a qualitative grasp of what's happening at the physical level. Although we tend to rely mostly on mathematical description, the qualitative treatment is valuable for people who are new to this topic.
I know you get many of these sorts of comments, but still, thank you so very much. I'm studying for my University Physics II exam and your videos are extremely helpful in laying out and simplifying these topics. You are a wonderful teacher and I am very grateful to you for sharing.
So nice and educative sir
It became clear for me straight when you made the comparison between mass'es inertia and inductance as a kind of inertia.Very good!
Very concise, analytic and easy to understand explanations. Now, all the gray arrears are clear. Many thanks
This video cleared up so much confusion! I was struggling to understand WHY exactly the inductor resisted changes in current. Thanks for the wonderful explanation.
short and crisp and to the point. Thanks and keep doing what you do
Thank you so much! My final is tomorrow and I'm so glad I found your videos
It’s late but hope u done good
@@billiejodavis776 Yeah😀
I wasted my education doing art... still fascinating trying to un thick myself🇬🇧😎👍
Best and simplest explanation ever. Wish you had been my electronics tutor.
I like your simplicity of explaining! I get confused though when you don't specify the current theory as conventional flow, especially with the basics. We all know only electron (electrons) flow is real, but we persist in pretending protons get out of the nucleus and somehow flow since Ben Franklin's presumption. I love to teach with great videos like yours, but unless you specify conventional flow or conventional current, the students get lost and frustrated at first.
I have my students learn it both ways and not fight it or they will fail to be pliable and tolerable learners. Thanks again sir!
Actually I have never thought of inductance that way and by comparing inductance to inertia this video explained a lot to me :)
wow that mechanical / electrical analogy was very revealing. thanks
In short it is only due to the "physical construction and geometry" of a coil which causes building and collapsing of magnetic field around the coil to induce an internal voltage in the coil (Faradays Law) called the counter emf. This counter emf opposes the supply emf or voltage (ac source or battery) causing the current to lag. Hope that is right?
This is the best explanation , really
I just came to listen to the sound the marker makes with the paper! ASMR!
from a fellow physics C teacher, excellent video
Love your method of teaching.
Thank you for sharing your knowledge ❤️🙏
That was quite helpful.....thanx and keep it up
It's a very nice explanation that is easy to remember.
Hi, I like your lecture. Thanks
Love these videos thank you
A big thank you for your great explanation. Really appreciated-
Kind of sad that this is the last playlist I am gonna watch on your channel. Thank you for uploading these videos. I guess, I am gonna be on my own for the thermodynamic chapters=(
Catch 22 great book
Awesome tutorials. Thank you so much 👏🏿👏🏿👏🏿
I assume that Lasseviren has taken the current flow in the direction of Electron movement rather than conventional current flow - which confused me a little bit but got the Point.
thank you for being so amazing and explaining things on an intuitive level
Thank you dearly, you're my savior!
Excellent Sir
Really well explained. Thank you so much!!
A very good analogy though, I like it.
Hi there . I am always having these two questions . In AC circuit it is said that current always keeps changing it's direction . If so , why we always have the same hot wire ( when testing with pen voltage tester) . Second question : Is there really any kind of movement for electrons in a wire when we apply some voltage ? Thank you so much for your help.
I have learned a lot from your videos.
The current changes direction because the voltage in the hot wire becomes negative. I am assuming you are wondering why the neutral doesn't become negative and the hot wire zero. The neutral is always zero in normal conditions.
Yes there is electron drift. In AC they just go back and forth.
Thanks for the expanation! So basically the inductor creates a potential difference between its leads so current can proceed to flow through it?
its the same principle we use in copper ballast of fluorescence tube. As the starter breaks the current flow, the magnetic flux in choke changes into high current which initiates arching inside the tube.
ok
I am surprised to see someone Disliked this Video which is so expressive!
Can you explain how this fact is useful in circuit designs?
I sometimes see an inductor used in power charging circuitry & I read that it stores energy to increase the charging voltage from a smaller input voltage to a larger charge voltage, but how can I know what the useful limits are in such a circuit to modify it for whatever purpose that I have?
What happens when the current stops abruptly? Will the current flow keep going as the flux reduces in the direction of "electron flow"? I guess I'm trying to understand why it wants to flow in a certain direction.
Love the ending example
So the induced voltage of the inductor purpose it to keep a constant magenetic field?
DUDE THAT WAS AWSOMEE!!!
Great analogies.
Great Video, thanks a lot.
I'm confused by the battery analogy. Are you saying when i is increasing the inductor is acting like a load, as if it's charging, storing energy like a battery? But when i is decreasing the inductor dumps energy and acts like a source battery. That's the way I see it from your vid. If the battery is charging the neg. terminal is pointing towards electron flow and when the battery is discharging the neg. terminal is pointing in the same direction as electron flow. Not easy to grasp but thanks.
he is considering the flow of electrons as current right? (instead of positive charges i.e the conventional current flow)
Love and love and love to you sir!
So nice thanks sir
Well done, sir.
At 4:30 you say the induced EMF pushes the current to the left. The confusing thing for me is : Does the induced EMF give a +-sign on the left side of the inductor and a -sign on the right side of the conductor? Or is it the reverse?
The induced EMF "tries" to push the current to the left. But the current is going to the right. The induced EMF gives a + sign on the left of the inductor and a negative sign on the right side of the inductor. EMF = -L di/dt. So if the current is growing then di/dt is + and the EMF is - (or is opposing the current). If the current is dimininishing then di/dt is - and the EMF is + (or is encouraging the current).
@@lasseviren1 Thanks so much for the reply!
@@Festus2022 You're welcome. Keep insisting that it makes sense, all the best!
nice logical explanations
really educational and really funny video. NATURE HATES CHANGE :DD
SO DIFFFIULT
Maybe you can make a video explaining why physics is required for any sort of useful college degree ;)
You are a beautiful human being :')
You saved me. Thanks a ton! :D
Nice sir
make in one video please all together, not divided by parts
Sorry if this is a dumb question, but what does the d stand for in -L*di/dt?
Think of it like the d is for delta - but the change is very small. So it's like a very small change in current over a very small change in time. Or the instantaneous rate at which the current is changing.
If you don't know this, you shouldn't be studying this topic at this level. It's like trying to calculate 5*5 before knowing 5+5.
d is change in something,so di is change in current divided by change in time as dv is change in velocity divided by change in time.
Thanks for the post sir.
I don't get it. I understand that by Farady's law that the current through the coil will create a magnetic field, and the change in flux will create an emf that counters the direction of the current from the circuit. But after it stabilizes, no more emf. So I feel there's only a one-time emf thing gonig on here. How is this useful?
Hey Pablo, you might have already had your question answered by now, but I thought I would take a crack at it anyways. You are right to think that once the current stabilizes that the emf will disappear. However, this would only happen if the current is not changing over time. For this case, a DC circuit which has a constant current, would not need an inductor unless there are other components changing the flux. However, with AC current, your current is constantly reversing itself over the inductor, producing that needed change.
Therefore,
DC current is constant = No emf over inductor after a long time.
AC current is ever-changing = Constant change in current and therefore an emf is produced for a longer period of time.
Thanks! It makes sense now.
Jacob Dwyer thanks
After taking more classes on electronics, I've learned more uses for inductors, incase anyone reads this! One certain application for inductors is filters! They can filter out electrical signals of certain frequencies. They can be combined with capacitors in different ways to change the flow of current (open circuit or short circuit) depending on the capacitance of the capacitor!
Pablo P yea true. bcuz when u get radio signals or TV signals. there is signal and no signal signal and no signal. using capacitor or inductor its always signal cuz it is discharging while theres no signal and its clear signal
If inductor opposes changes in current by inducing a voltage opposite to the source voltage, then shouldn`t that induced voltage oppose the source voltage throughout resulting in zero current in the circuit..... why then current still flows in the circuit........ what is driving this current ..... how is the opposition to that current is reflected
good stuff
Delighting!
great video, thanks
1:37 *magnetic field
Thanks a lot.......
Fixed current is irrelevant to magnetic flux ;
Please indicate the change in current
The subject of magnetism is not simple including the the effect of an IRON as a core and the concept of magnetic saturation. .
Professors suck because they are 100 years old and way too advanced to teach basic physics. RUclips is the best place to learn physics. Thank you lasseviren1.
good
thanks alot
WHAT IS IMPENDENCE/WT IS OP-AMP
Maybe I’ve smoked to much of the naughty stuff and drank too much in my young years. Idk but my brain seems kinder fried and would like to run away fast on an open empty field from all this stuff. But I want to be an electrician so I guess I’ll need it (I think).
:(
oh no, I dont think it's wise to compare force with electromotive force (towards the end of the video) because they're actually different. EMF is more of a work done to carry a charged particle, and hence, not a force.
+Illustraits Illustraits That's right, emf is not force, inductance is not mass, and di/dt is not acceleration. That's why they are called analogs.
+Illustraits Illustraits But it's deeper than Adele.
Is it just me, or does he actually sound like Willem Dafoe!!
Mutual inductance.. gravity
Thanks
shit i died at 9:00 REVELATION !! TAM
This is what I mean when I say that old schoolbooks from 1935 don't mention inductors store energy because they knows that it sludge from one side to the other when you changes the flow .store back then means you can disconnect the inductor and when you need it later you can use it
:')
Sluggishness
expert, the -ve 1 is not needed.
Excellent 🙏🙏🙏🙏
thanks