As many people here comment, (also IMHO) you are the best tutor i've ever listened to. ... Your explanations are gold. Pure gold. Im enjoying it so much.
RIGHT? This guy is utterly amazing. If I manage to invent/design something I'll be including your name on the patent! Since I was a young boy, I've always felt that the future of transportation, among other things, will be dictated by some manipulation of the EMF. These videos have sharpened my understanding of many things, and for that sir, I thank you.
If you're looking for the next wave of technology then understanding magnetism, other than what is presented, is vital. There is great explanation in these videos and only helps compound the proofs of more to the equation than meets the eye. Viktor Schauberger and his work(books, patents;not nonsense videos people post about him today) will help anyone on this path.
I must say that you have hands down the best tutorials for A Level physics. What I love is that you don't leave out the important maths that is involved in learning these concepts (the a level physics syllabus has a suprisingly small amount of math involved)
Covers every single point in the syllabus in a simple, easy to understand way. I learnt more in 45 minutes than what we learnt in 2 weeks of lessons. Thanks!
Yes. If you go to my A Level Revision playlist you will find that videos 29-38 fit the bill. There is also a separate playlist on quantum mechanics with several videos at a deeper level than A level.
Your videos have helped solidify my understanding of electricity principles. I am delighted. Thank you so much for taking the time out to publish these!
i graduated high school in 2005, trashed physics at A-level in Hong Kong. now im getting older and like to revise on these stuff. I wonder if i had a teacher like you back then, i wont be where im sitting now. Thanks and i must say, you are a great teacher!!! Ray from Australia
Dude seriously its good to hear that you still have interest in something that you were not good at. People get scared from maths or other subjects at which they are not good however when you study from scratch and make notes and collect other helping stuff you can easily cover any subject at least this is what i believe in. Good to hear that you haven't given up even though you might never have any relation to this topic in the coming years.❤
I am a high school physics teacher and I have listened to a lot of RUclipsrs derive Maxwells equations and you have done imho the best job that a high school student can understand
Just wanted to say thanks for your super clear videos! I can't get over how you make complicated topics seem extraordinarily simple. (I'm more so referring to your video on how you derived Maxwell's 4 equations, but still great nonetheless!) As an electrical engineering/physics major I am thoroughly enjoying these videos.
You sir are an excellent teacher! I have watched, read, and listened to many of these concepts many times over the years and while I understand a good bit fairly well by now, many points you went over I just now finally can understand thanks to you and your explanations. I still plan to watch this again and practice the math by hand, but you explanations make this complicated subject MUCH easier to ingest. Thank you VERY much for this and your time!!
Yes, I could see that was your point. By the way, out of curiosity I looked at the web for other accounts and other graphs and was astonished to find this to be a common error. Of course the square root of the power would look like the absolute value of sin, which may be in the back of people's minds. Anyway, as I said, otherwise, I thoroughly enjoyed your lesson!
You will get hurt if you hold the neutral wire. Please don't try it. In the UK the colours are red/brown for live, blue/black for neutral and green/yellow for earth. If you touch either the live or neutral you could get a shock.
All A level videos are AMAZING!! Badly needed these explanations! :) Thankyou SOO much for this. Can't thank enough :') Your explanations are great. Concepts are perfectly clear now! Stay blessed, sir
Thanks alot DrPhysicsA... Your videos are extremely helpful.. more so than attending a physics class... because you explain everything so well and clearly. :D
Thank you very much for your effort. I am a civil engineer, I wish I had you as a teacher in college courses, I might understand AC today! Thanks again
Good questions. More about technology than physics. The windmills have a very clever gearing device which is capable of self adjustment to ensure that the turbine itself produces electricity at the appropriate frequency. The entire national grid monitors demand on a moment by moment basis and can switch in or out additional generators as the case may be.
Super Tutor... helped me greatly, always struggled in college with electronics & the math side of things... if only they had the staff.. but its all coming back and makes perfect sense. thankyou
Yes that's true but the Capacitor holds a much more steady voltage so this is the steady voltage which applies even if another voltage source in the circuit falls.
I would point out that the representation of the Sin squared waveform (explained from around 19:44) is incorrect. It does not look like a full rectified sine wave - in fact it is a sine wave of double the frequency, centered at 0.5Vo. That is where the average value of 0.5 comes from (since the average of the sine wave component is zero).
Well spotted. At 3:57 it should indeed be the right hand rule (rlght hand for generators - left hand for motors). I have made an annotation. Thanks for spotting this. As far as your second question is concerned, unless there is something I have missed an LED will light only when it is forward biased (ie the current flows in the forward direction thro it). Otherwise no current flows and the LED doesn't light. Perhaps there is more to it in your text book. Is it something to do with decay time?
Excellent - Thank you very much. I think some explanation is needed on the two back diodes on the FWR(@41:18). I guess the two back diodes 'meet' at DC Ground?
just saying (cuz i love pointing errors out :p) the graph at 17:54 is a mod(sin theta) graph google sin^2 graph for how an actual sin^2 graph looks like
There is a difference between a generator and a motor. In the former case you turn a coil in a magnetic field. There is a phase difference in this case between the maximum flux linkage and the maximum current. in the case of the motor current flows in the coil in the presence of magnetic field causing the coil to turn. In this case there is no phase delay between the maximum voltage and current.
the root mean square is the average voltage and average current that the resistance load can sense , since it doesn't detect a change in the direction of flow , of current or voltage. unless adding a magnet to the load , it starts sensing the change and starts motion
Thats a great video! But you might have made a mistake. In the beginning of your tutorial, when you determined the direction of the current in the coil of an ac generator when it's turned in a clockwise direction, you used flemmings left hand rule. Instead, you should have used flemmings right hand rule. If you did so, the direction of the current would be opposite to the direction you specified. This is all because in ac generators, the induced e.m.f follows the Flemmings right hand rule.
Rudra Ghosh He used left hand rule to find the current direction from the direction of the external magnetic field and the direction of the force acting on the loop of wire. This is correct since the right hand rule works for the cross product of the current and the external magnetic field direction, essentially giving the inverse.
I'll put it on my "to do" list. Meanwhile have you seen the excellent videos of Leonard Susskind's lectures on String Theory which you can find on RUclips?
Re Q2: A filament bulb on an AC circuit is being turned on and off at a rate the same as the frequency of the alternating current, for example 50 times a second, because this cycle is so fast the filament does not have time to cool down and loose light output. An LED (Light emitting DIODE) only allows current to travel in one direction, the light is not produced by heating a filament so as soon as power is cut the light stops. On AC this will happen for every negative voltage cycle.
Sagar - In this case the V^2 term applies to the voltage in the wire, not the load. It is better to think in terms of the formula P=I^2R (1) for power dissipated in the transmission cables. Since P=VI, if we double the voltage that we are sending down the cable, to get the same power at the end the current is halved. But, because of the I^2 term in (1), the power "wasted" in the cables goes down by a factor of 4. Or look at it another way - we need a 1/4 of the copper to transmit the same power. The downside is that we need more insulation, but that is cheaper, and lighter than copper. In many cases we can even rely on air to provide the insulation.
at 37:03 , why can't we use v^2/R? and when I tried it... the power loss is greater at 10000 V even though when I^2R was used, the power loss was lower at 10000V. I'm confused 😕
+Prashanthi Narangoda We use I^2R because current is constant through circuit. If you use V you need to use the potential drop along the power lines only.
You have some highly educational videos! i'm watching these to refresh my school from a few years back and just out of general interest in understanding electricity :) thanks
I see how you derived the formula for the average Voltage in AC at 20:41 and it does make sense. However I wonder what does another way of deriving it really mean: 1. I integrate the equation of Voltage from 0 to T/2 (taking only positive area): Integral[V0 * sin(omega*t) dt] from 0 to T/2. The result is -V0 * cos(omega*t)/omega from 0 to T/2. Evaluating gives me: V0 * T / pi. 2. I take the area under the curve and divide by change in T -- the length of the bounds of integration: V0*T/pi*(T/2 - 0) = 2V0*T/pi*T = 2V0/pi. Therefore I could conclude that the average Voltage is 2V0/pi. However this value is obviously much different than V0/sqrt(2). What does this quantity represent? Does it have a name? Thanks for all your videos, they are great in helping me understanding a variety of topics in physics. You are amazing at explaining things with simple words, yet not abstaining from maths :)
4:22 due to lenz's law the direction of the induced current is always such to oppose the change that causes the current. Therefore shouldnt the current be in the opposite direction to oppose the turing force of the generator? Im confused someone help.
7:45 I have another idea by Maths at this point the current would have passed an angle of 270 And sin270=-1 so that's why the Vmax is in opposite direction :D
Yes. It is the left-hand rule for motors and the right-hand rule for generators. I think I may have added an annotation to correct an error. But I know that not everyone can see the annotations.
DrPhysicsA Actually, it is either. As long as the rules are consistently applied. If you choose to use the right-hand rule for a generator then you must also use the right-hand rule for a coil and the right-hand rule for a conductor and the left-hand rule for a motor. You can switch which hand to use to apply the rules if you apply all of the associated rules to that hand also. It is quite similar to the difference between conventional theory current flow and electron theory current flow. Does current flow from + to -, or - to + ? No one truly knows. But if one consistently applies the theories and rules throughout their work then their work will make sense.
At 9:00 minutes roughly in the video. you only talked about the left wire in the loop changing direction, what about the right one? Did it get lost in a Blackhole?
I'm not sure if someone in the comments has said it or not, but PLEASE do not just stick a large cap in the circuit! You'll waste a lot of power that way. If you were using a Three Terminal Regulator, then the larger your Vmin is (the lowest trough that the capacitor discharges too), the more power is on the input of the regulator. A TTR only needs Vmin to be at least a certain voltage above your desired output voltage load, which in the case of the LM317 is 2V. Then to calculate power dissipated by the TTR, you take the power of the input from the full-wave rectifier and capacitive filter minus the expected output power. Only using the Vmin you need rather than an excessive Vmin can lower the abuse your device will take in terms of heat/necessary cooling!
hi i love your videos. They have helped me out alot.. Could you please do the unit 4 past paper questions?? i really need help with those especially multiple choice
I know a lot of people puzzle over this. They say: why do we look at power loss as I^2 * R and thus make I as low as possible. Why not look at power loss as V^2 / R and then make V as low as possible? The reason is that if you look at the V^2/R option you are looking not at the voltage coming from the transformer but the voltage drop across the power lines which will be a tiny fraction of the voltage on the power line.
It can be other equations of power. Like V^2/R but remember the power dissipated across the resistor is the voltage across that resistor x I. And V= IR so in his example of 10 kV vs 250 V: considering the 250 V example; the power was constant therefor the current = 4A So V=IR =4Amps x 10 Ohms therefore V=40 and V^2/R =1600/10 = 160W dissipated. Sorry for the long explanation.
I was a government scientist, then a more senior manager. I was never a teacher but I have given lectures on various subjects.
You are such a wonderful teacher Sir. I struggle most in Physics and you've made it almost easy! May God bless you for all your help.
As many people here comment, (also IMHO) you are the best tutor i've ever listened to. ... Your explanations are gold. Pure gold. Im enjoying it so much.
Many thanks.
RIGHT? This guy is utterly amazing. If I manage to invent/design something I'll be including your name on the patent!
Since I was a young boy, I've always felt that the future of transportation, among other things, will be dictated by some manipulation of the EMF. These videos have sharpened my understanding of many things, and for that sir, I thank you.
If you're looking for the next wave of technology then understanding magnetism, other than what is presented, is vital.
There is great explanation in these videos and only helps compound the proofs of more to the equation than meets the eye.
Viktor Schauberger and his work(books, patents;not nonsense videos people post about him today) will help anyone on this path.
That's a noble ambition. For A level it isn't necessary to have the full detail which of course requires an understanding of quantum mechanics.
I must say that you have hands down the best tutorials for A Level physics. What I love is that you don't leave out the important maths that is involved in learning these concepts (the a level physics syllabus has a suprisingly small amount of math involved)
Covers every single point in the syllabus in a simple, easy to understand way. I learnt more in 45 minutes than what we learnt in 2 weeks of lessons. Thanks!
Yes. If you go to my A Level Revision playlist you will find that videos 29-38 fit the bill. There is also a separate playlist on quantum mechanics with several videos at a deeper level than A level.
Thanks for kind comments. On Pauli, have you seen my videos on Atomic Physics which cover Pauli?
Love every episode from this great guy.
Your videos have helped solidify my understanding of electricity principles. I am delighted. Thank you so much for taking the time out to publish these!
This is the best physics tutorial I've ever seen in my entire life
After 55 years of turning switches ON and OFF I at last understand what really is going on. I think you earn a Nobel Prize for Education!
Perfectly said! I absolutely loved this. Very well spoken.
Fabulous, just what I was needing at this point in my power engineering studies! Thank you!
i graduated high school in 2005, trashed physics at A-level in Hong Kong. now im getting older and like to revise on these stuff. I wonder if i had a teacher like you back then, i wont be where im sitting now. Thanks and i must say, you are a great teacher!!!
Ray from Australia
Dude seriously its good to hear that you still have interest in something that you were not good at. People get scared from maths or other subjects at which they are not good however when you study from scratch and make notes and collect other helping stuff you can easily cover any subject at least this is what i believe in. Good to hear that you haven't given up even though you might never have any relation to this topic in the coming years.❤
Aside from the relativistic nature of electron flow, these lectures are very clear cut and easily understood. Very good job!
RUclips should have more speed options - 1.5x is too slow, 2x is too fast
1.75x would really be useful here
oh btw, GREAT VIDEO!!
Im thinkin ab 2.5x 😂🤣
Its available now
get off the meth ...
I am a high school physics teacher and I have listened to a lot of RUclipsrs derive Maxwells equations and you have done imho the best job that a high school student can understand
Just wanted to say thanks for your super clear videos! I can't get over how you make complicated topics seem extraordinarily simple. (I'm more so referring to your video on how you derived Maxwell's 4 equations, but still great nonetheless!)
As an electrical engineering/physics major I am thoroughly enjoying these videos.
You are a good teacher . Thanking for posting your video . All your Videos are Good and its helpful to all the students. THANK YOU!
This guy is the best i am even planning on not attending lessons just to listen to him
You sir are an excellent teacher! I have watched, read, and listened to many of these concepts many times over the years and while I understand a good bit fairly well by now, many points you went over I just now finally can understand thanks to you and your explanations. I still plan to watch this again and practice the math by hand, but you explanations make this complicated subject MUCH easier to ingest. Thank you VERY much for this and your time!!
Still watching your videos after 9 years, you're a wonderful teacher
YOU ARE GOD TO ME! THANKYOU! I DON'T CARE IF I SCREW UP THIS PRE BOARDS BUT I FINALLY GET IT! THANKYOU SIR!
watch at 1.5x speed. save ur time and use it else where
supermegablurgh 1.25 speed is better. Lol, u got a nice tip, btw. haha!
supermegablurgh 2x speed if you got game
yes r8 thanks
It may be easier for you to interpret.
But it is important to keep the speed such that the flow of ideas must not be too fast to follow.
Yes, I could see that was your point. By the way, out of curiosity I looked at the web for other accounts and other graphs and was astonished to find this to be a common error. Of course the square root of the power would look like the absolute value of sin, which may be in the back of people's minds. Anyway, as I said, otherwise, I thoroughly enjoyed your lesson!
You really are a hero, great teaching mate!
You will get hurt if you hold the neutral wire. Please don't try it. In the UK the colours are red/brown for live, blue/black for neutral and green/yellow for earth. If you touch either the live or neutral you could get a shock.
This video is simply awesome. never thought AC Current would be so easy to learn
All A level videos are AMAZING!! Badly needed these explanations! :) Thankyou SOO much for this. Can't thank enough :') Your explanations are great. Concepts are perfectly clear now! Stay blessed, sir
Thanks alot DrPhysicsA... Your videos are extremely helpful.. more so than attending a physics class... because you explain everything so well and clearly. :D
My A Level Revision playlist should contain most of the material needed at both AS and A2 level.
Actually the paper is white but the lighting is such that it takes on the colour of the walls. Well spotted. Thanks for kind comment.
Thank you very much for your effort. I am a civil engineer, I wish I had you as a teacher in college courses, I might understand AC today! Thanks again
Good questions. More about technology than physics. The windmills have a very clever gearing device which is capable of self adjustment to ensure that the turbine itself produces electricity at the appropriate frequency. The entire national grid monitors demand on a moment by moment basis and can switch in or out additional generators as the case may be.
please note that your sin^2(wt) at 19:25 waves should be smooth as they are actually just -1/2cos waves translated up 1/2
Super Tutor... helped me greatly, always struggled in college with electronics & the math side of things... if only they had the staff.. but its all coming back and makes perfect sense. thankyou
Yes that's true but the Capacitor holds a much more steady voltage so this is the steady voltage which applies even if another voltage source in the circuit falls.
I would point out that the representation of the Sin squared waveform (explained from around 19:44) is incorrect. It does not look like a full rectified sine wave - in fact it is a sine wave of double the frequency, centered at 0.5Vo. That is where the average value of 0.5 comes from (since the average of the sine wave component is zero).
Well spotted. At 3:57 it should indeed be the right hand rule (rlght hand for generators - left hand for motors). I have made an annotation. Thanks for spotting this. As far as your second question is concerned, unless there is something I have missed an LED will light only when it is forward biased (ie the current flows in the forward direction thro it). Otherwise no current flows and the LED doesn't light. Perhaps there is more to it in your text book. Is it something to do with decay time?
For a generator yes. What point on the video is this? I may have added an annotation to clarify.
Thanks. Laziness on my part. I was trying to show that the sine squared term is all positive, and didnt draw the wave shape correctly.
Your presentation on Transformers was more than meets the eye :)
Excellent - Thank you very much. I think some explanation is needed on the two back diodes on the FWR(@41:18). I guess the two back diodes 'meet' at DC Ground?
You saved my grades yet again. Thankyou!
Appreciate the effort. Keep up the good work!
This is really good, I searched through all your videos and find those relevant to my modules, much help!
yes!
Amazing tutorial. Keep up the good work and know you are doing good work paying your knowledge forward.
Such a wonderful video and quite easy to grasp the basic concept in impedance. Thankyou so much.
Thank u Dr physics u r the best teacher u have clear my concepts instead of rot learning
just saying (cuz i love pointing errors out :p)
the graph at 17:54 is a mod(sin theta) graph
google sin^2 graph for how an actual sin^2 graph looks like
PS. not by any means trashing you . you are AMAZING.just an error i found
There is a difference between a generator and a motor. In the former case you turn a coil in a magnetic field. There is a phase difference in this case between the maximum flux linkage and the maximum current. in the case of the motor current flows in the coil in the presence of magnetic field causing the coil to turn. In this case there is no phase delay between the maximum voltage and current.
your videos are great, I downloaded most of them. THANK YOU.
the root mean square is the average voltage and average current that the resistance load can sense , since it doesn't detect a change in the direction of flow , of current or voltage.
unless adding a magnet to the load , it starts sensing the change and starts motion
All in all, it is an amazing work, thank you!
Thats a great video! But you might have made a mistake. In the beginning of your tutorial, when you determined the direction of the current in the coil of an ac generator when it's turned in a clockwise direction, you used flemmings left hand rule. Instead, you should have used flemmings right hand rule. If you did so, the direction of the current would be opposite to the direction you specified. This is all because in ac generators, the induced e.m.f follows the Flemmings right hand rule.
Rudra Ghosh He used left hand rule to find the current direction from the direction of the external magnetic field and the direction of the force acting on the loop of wire. This is correct since the right hand rule works for the cross product of the current and the external magnetic field direction, essentially giving the inverse.
Rudra Ghosh He basically gave the non-conventional direction.
I'll put it on my "to do" list. Meanwhile have you seen the excellent videos of Leonard Susskind's lectures on String Theory which you can find on RUclips?
Re Q2: A filament bulb on an AC circuit is being turned on and off at a rate the same as the frequency of the alternating current, for example 50 times a second, because this cycle is so fast the filament does not have time to cool down and loose light output.
An LED (Light emitting DIODE) only allows current to travel in one direction, the light is not produced by heating a filament so as soon as power is cut the light stops. On AC this will happen for every negative voltage cycle.
Because an alternating current has a voltage vs time pattern which follows that of a sine wave.
Hats Off to yuh Sir .. your lectures are Supeeeerrrrrrrrrrrrrrrr Awesomeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
Hi, how do u know cutting of magnetic flux is left hand rule? Isn't it a generator?
Sagar -
In this case the V^2 term applies to the voltage in the wire, not the load. It is better to think in terms of the formula P=I^2R (1) for power dissipated in the transmission cables. Since P=VI, if we double the voltage that we are sending down the cable, to get the same power at the end the current is halved. But, because of the I^2 term in (1), the power "wasted" in the cables goes down by a factor of 4. Or look at it another way - we need a 1/4 of the copper to transmit the same power. The downside is that we need more insulation, but that is cheaper, and lighter than copper. In many cases we can even rely on air to provide the insulation.
Thanks graham.... I was just assuming the entire voltage across the cables... that's so silly of me...
at 37:03 , why can't we use v^2/R? and when I tried it... the power loss is greater at 10000 V even though when I^2R was used, the power loss was lower at 10000V. I'm confused 😕
+Prashanthi Narangoda We use I^2R because current is constant through circuit. If you use V you need to use the potential drop along the power lines only.
+DrPhysicsA Ohh! I get it now (: Thank you
i like this, your explanations are so very clear
I jst luv ur videoes ur xplainations r crystal clear
thank u
You have some highly educational videos! i'm watching these to refresh my school from a few years back and just out of general interest in understanding electricity :) thanks
I see how you derived the formula for the average Voltage in AC at 20:41 and it does make sense. However I wonder what does another way of deriving it really mean:
1. I integrate the equation of Voltage from 0 to T/2 (taking only positive area): Integral[V0 * sin(omega*t) dt] from 0 to T/2.
The result is -V0 * cos(omega*t)/omega from 0 to T/2. Evaluating gives me: V0 * T / pi.
2. I take the area under the curve and divide by change in T -- the length of the bounds of integration:
V0*T/pi*(T/2 - 0) = 2V0*T/pi*T = 2V0/pi.
Therefore I could conclude that the average Voltage is 2V0/pi. However this value is obviously much different than V0/sqrt(2). What does this quantity represent? Does it have a name?
Thanks for all your videos, they are great in helping me understanding a variety of topics in physics. You are amazing at explaining things with simple words, yet not abstaining from maths :)
a big thanks from tunisia :) your videos are really helpful
At 47:08 , in the rectifier bridge why do we need the diodes which are connected on the left side is there a reason behind it? Thanks
+Bharat Trehan Is this explained at 41:05
Excellent!!!
Thank you so much,
4:22 due to lenz's law the direction of the induced current is always such to oppose the change that causes the current. Therefore shouldnt the current be in the opposite direction to oppose the turing force of the generator? Im confused someone help.
Very well delivered. Thank you!
@DrPhysicsA, will u be able to do a video on the topic of Torque and Moments of Inertia, and the integrations to do with it?
7:45 I have another idea by Maths at this point the current would have passed an angle of 270 And sin270=-1 so that's why the Vmax is in opposite direction :D
ONLY ONE WORD FOR YOU....YOU ARE AWESOME!!! THANK YOU!!!! :)
It was quite helpful for me.. Thanx alot sir
few of my concepts got clear after this lecture ☺
how would you calculate peak voltage or current by?
V0 = VrmsXroot2
I thought for generator as it is induced we have to use right hand rule not left...
Yes. It is the left-hand rule for motors and the right-hand rule for generators. I think I may have added an annotation to correct an error. But I know that not everyone can see the annotations.
DrPhysicsA Actually, it is either. As long as the rules are consistently applied. If you choose to use the right-hand rule for a generator then you must also use the right-hand rule for a coil and the right-hand rule for a conductor and the left-hand rule for a motor. You can switch which hand to use to apply the rules if you apply all of the associated rules to that hand also. It is quite similar to the difference between conventional theory current flow and electron theory current flow. Does current flow from + to -, or - to + ? No one truly knows. But if one consistently applies the theories and rules throughout their work then their work will make sense.
DrPhysicsA By the way, Very well done video Sir.
Can I have all the sheets you've filled so far? :3
Thank you very much for these videos!
Many thanks. Very kind.
9:15 Shouldn't it be positive -> negative -> positive 50 times a second?
Kind Sir, thank you very much for this lesson, do you have anything on balance three phase electric power systems?
Thanks
Very interesting and helpful, thank you very much.
so what is the graph of current vs time in ac voltage?
At 9:00 minutes roughly in the video. you only talked about the left wire in the loop changing direction, what about the right one? Did it get lost in a Blackhole?
this is very excellent work,now i have a very clear understanding :D
I'm not sure if someone in the comments has said it or not, but PLEASE do not just stick a large cap in the circuit! You'll waste a lot of power that way.
If you were using a Three Terminal Regulator, then the larger your Vmin is (the lowest trough that the capacitor discharges too), the more power is on the input of the regulator. A TTR only needs Vmin to be at least a certain voltage above your desired output voltage load, which in the case of the LM317 is 2V. Then to calculate power dissipated by the TTR, you take the power of the input from the full-wave rectifier and capacitive filter minus the expected output power. Only using the Vmin you need rather than an excessive Vmin can lower the abuse your device will take in terms of heat/necessary cooling!
Brilliant video! Thank you!
hi i love your videos. They have helped me out alot.. Could you please do the unit 4 past paper questions?? i really need help with those especially multiple choice
Nice Explanation Sir, Thanks
to clarify.... for their to be a voltage the current in wire must cut through and be perpendicular to the lines of the magnetic field?
so if we use the right hand rule the direction of the current of the wire would be the other way around right?
Yes. LH rule for motors and RH rule for generators.
for low amount of voltage, does cellphone sustain corresponding high amount of current while charging?
thanku man u r my savior 💕
sir do you have video on binding energy,radioactive decay,and quantum phys????reply asap pleaseee
Very Good Explanation!!!!
really , you're so wonderful ^_^ thank you
Is the ac current movement like water wave, their drift velocities going back n forth from equilibrium positions?
We mustn't confuse the sinusoidal wave associated with alternating current with the drift velocities of the individual electrons.
Why is the power loss given by the equation I^2 R only and not any other equation of power?
I know a lot of people puzzle over this. They say: why do we look at power loss as I^2 * R and thus make I as low as possible. Why not look at power loss as V^2 / R and then make V as low as possible? The reason is that if you look at the V^2/R option you are looking not at the voltage coming from the transformer but the voltage drop across the power lines which will be a tiny fraction of the voltage on the power line.
It can be other equations of power. Like V^2/R but remember the power dissipated across the resistor is the voltage across that resistor x I.
And V= IR so in his example of 10 kV vs 250 V:
considering the 250 V example; the power was constant therefor the current = 4A
So V=IR =4Amps x 10 Ohms therefore V=40
and V^2/R =1600/10 = 160W dissipated.
Sorry for the long explanation.
why was the grid set for 50/60 Hz? what is the approximate energy efficiency (%) for, say 100W, 50/60 Hz transformer ?
99.50%- 99.75% a little energy is lost due to eddy currents and resistance factor