Potentiometer principle (logic) & working | Electricity | Physics | Khan Academy
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- Опубліковано 12 січ 2025
- Let's explore, logically, the working principle of a slide-wire potentiometer. A potentiometer can measure voltages, with higher accuracy than a voltmeter, without drawing a current from the main circuit.
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Created by Mahesh Shenoy
U know what?
May be this is the only channel where u come to learn something without any paper and feel the equal happiness like u was doing some research and u reached to a decision
It's srsly amazing
I kid you not, you are such an amazing teacher!
i agree🙋🏻♂️
Actually he is but just because he haas best, cool and awesome student like us
Indeed he is❤️
Sach me itne hard topics ko bhi kitni choti time period me samjha dete hai
After hours of classes, hundreds of confusion, tons of demotivation. This is the type of explanation I was looking for!
Thanks for making me feel less dumb today
Great job, thanks 💕
5 minutes into this video and I'm already commenting..that's how incredible khan academy(India) videos are!!!!
Reasons for not balancing:
1. The potential difference between the ends of the potentiometer wire or the emf of the cell connected in the main circuit may not be greater than the emf of the cells whose emf are to be compared .
2. The positive terminals of the cells and the battery used in the circuit might not be connected to the same end of the potentiometer wire.
You're welcome!
Can u please elaborate the second reason?
@@atchayap1434 you know when we connect a measuring device in a circuit we connect +ve end to +ve terminal of a cell and -ve end to -ve terminal. so u will have to connect them the right way.
i think this is what the 2nd point is trying to say
the best explanation I have seen so far , really appreciate your work , thank you!! :)
The way I said "NO" out loud when he ended the video without answering the question...😫
There shall be sleepless nights searching for the answer in your dreams : P
@sapphireblue9209 the other case would be when the 9V battery connected to the long wire is in opposite polarity. There would be no way for it become equal to the voltage across the resistor no matter how much you adjust the length.
Sir, khan academy is life saviour 🙏. No thanks would be enough to thank you guys. You inspire me to do my work with passion too.
Great reply
Iam so confuse about this topic and watch so many videos but still remain confused but now im clear about it becoz of u sir how clearly u had explain thanku soo much😊🥰
Damn. My physics teacher is intelligent and I respect him. But bro you just teach it in a way that makes it seem so intuitive. Love you man ❤
What an amazing, pleasing and charismatic way of explaining!!!!
How is that possible😳 AMAZING
Yahi toh btaya bhai ki kaise possible , kya pdhai krega re tu 🤦🏻
If we put connect the negative electrode of the unknown emf with the positive (opposite) end of the potentiometer wire, then the current will always enter the secondary circuit.
I think this could be an answer to your question!
Ohh I had the same thought, but wasn't sure!
What about this:- Resistance of wire too high we are using so not gave that potential difference.
Im a student from Pakistan and your teaching is incredible, I wish to have a physical teacher like u!
Great teacher. You made physics easy 🙏
You are a life saver man 🔥
Love your work from Sri Lanka
The best explaination on UA-cam so far. You are a skillful teacher. So helpful for us.
this is the only channel aside physicswallah where one can truly and logically understand things
One of the amazing and talented teacher i have ever seen
*_Summary Of The Video :-_*
*Potentiometer*
* We use a voltmeter to measure the potential difference (Voltage) but it does not give us accurate value.
Because it draw some ammount of current from the circuit. Which can change the value of Voltage as well.
* We can measure the accurate value of Voltage by using a _Potentiometer_.
*Principle Of Potentiometer -* The principle of a potentiometer is that the potential dropped across a segment of a wire of uniform cross-section carrying a constant current is directly proportional to its length.
*Wire Used In Potentiometer -* Generally alloys like constantan or manganin are used as potentiometer wire because they posses high specific resistance and low temperature coefficient
*Null Point or Balancing Length Of The Potentiometer -* The balancing point or null point of the potentiometer is the point on the slide wire when the galvanometer shows zero deflection.
*Primary Circuit & Secondary Circuit -* primary circuit consists of a secondary cell( driver cell). and a secondary circuit is the one in which the primary cell whose emf is to be determined is connected.
*Potential Gradient -* Potential drop per unit length of the wire is known as potential gradient.
*Sensitivity Of Potentiometer -* Sensitivity of Potentiometer means the smallest potential difference that can be measured by using it and this can be achieved by decreasing the potential gradient by increasing the length of the wire.
Great help to prime ourself for the material
Nobodys gonna read dat
Thank you for this amazing video!!💐
Awesome! I was looking for explanation on potentiometer and this did justice!🔥🔥🔥
oh wow beautifully explained.im a student from Sri lanka
Thank You So Much! I can't thank you enough for this. I just wanted you to know that you're helping students like me to understand fairly complicated topics like this. Keep up the good work👍 and I hope more people benefit from this. Cheers, Advik. 😄
Sir you are like a god ,
You clear my concept of potentiometer through this small 10min video even i could not understand concept of potentiometer in 1hour lecture of my coaching institute♥️♥️♥️♥️♥️
Sir you are really awesome
I am grateful to you
Be blessed by the divine
Please do make an official playlist
You are a blessing ♥️♥️♥️
He is a gem. Preserve him.
Fuck cringe
👌I'm really happy..listening to ur vedios
Oh dear, I love these videos!
I love this guy.
This guy is so amazing.....
I love and admire your logic all the time👍👍👍🙏
Underrated channel
sir has some super power to get into everyone's mind and make them visualise! (I'm Jee 2025)
This is not in syllabus brother
@@Exhilarated1750it is
Very nicely explained! Great job
Super explanation sir💥💥thank you 😊
Last question solution
It will never be zero if the + terminal of driver battery is not comnected to + terminal of the place where voltage is measured.
Great take. I had so many questions about the assumptions already made about length and the way connections were made in the circuit.
Thank you. ❤️
omfg this makes so much more sense
You are just amazing! sir.
Thank you very much Mukesh
LV Ur way of teaching ❤️
Well explained.. Thank you
simply amazing
Thanks 😊
Thanks Mr musk for funding
Just thank you!
The other answer should be that if we were to connect a resistor in series to the battery, some voltage would drop through the resistor, availing lower voltage drop across the wire, hence zero deflection cannot be found in the wire
How come u get it..wow👏
Ohh so your name is Mahesh..
Can I consider the case where the internal resistance of the 9V battery is large enough that the potential difference across the wire is less than the unknown potential difference? That, or as my lab teacher used to say, loose circuit XD
Nice try, but I would still put this under the first category. Even if the p.d. across the wire is large enough, there is still a possibility of not getting a null-point.
@@KhanAcademyIndiaEnglish does it have something to do with the direction of deflection of galvanometer at the start of the experiment on the two extremes of the wire? Say, if the deflection occours towards the same side than null point can never be reached?
@@pranavsrikanth935 Yes, you are onto something. But, what set-up do you think would cause that?
@@KhanAcademyIndiaEnglish what if the potential gradient of the wire is greater than the voltage/emf we are trying to find?
@@KhanAcademyIndiaEnglish When the length of the wire is less than required...?
It works slightly on the principle of meters bridge
Thank you sir !
You are amazing
Thank u soooooooooooooo muchhh❤
this is so helpful , thank you so much sir
If you reverse the polarity of one of the two batteries then no matter how long you slide the slider over the wire,,but Everytime you will fail to get the zero deflection in galvanometer.....I hope I have given a satisfactory answer.....please reply sir.....
Reminder: Not in syllabus of cbse as well as jee mains⚠️⚠️
Really?
But the question has been put up in 2024 jee mains so don't avoid anything....moral of the story' jee pe bhrosa nhi Krna h vo out of syyllbus hi dega😢😢
This guy forgot to edit at 2:40!!
Nice catch!
lol after 2 years
i knew it was you from your voicee and vibes 😂😂 i really love your vids btw. you are one of the reasons for me to pursue pure sciences in my college.your energy while is sooo cool keep up the good workkk 💗💗
passionately curious
Thank youu sooo much sir! Your explanations are very clear and interesting as well!!
Just GENIUS!!!!
It's all inspiring.thank u sir. Sir can u kindly tell me which kind of app or technology do you use to make such videos.
Tysm
Amazing teaching
When the galvanometer is faulty
You explain very well
I think if we increase the resistance of the connecting wire through which we slide the jockey, by ohm's law the potential accross the wire should decrease, and if we decease it below the potential acroos the load, we might never find a null point
amazing explanation!
Thank you sir
amazing
Sir this concept don't work with bulbs/resistance as they are not applying a specific P.D they will apply P.D according to the circuit which will never be equal to the potential across the potentiometer wire as P.d would only be equal if there was no galvanometer there... Other wise it will violate the parallel resistance law. What I mean is that p.d of the bulb will adjust to the circuit but this concept only works for something which works at a fixed potential like a battery.
If potential difference is far more smaller that it becomes difficult to adjust wire as it will always show some deflection in galvanometer, I think in that case we will never achieve it 🤔
What if the batteries are arranged in reverse configuration then even if the p.d of lower battery is greater than the upper one still there will be current
When the negative terminal of cell in secondary cir cuit is connected to positive terminal of driving cell then also we can never get null deflection .
Omg this is the best
Thankyou sir...
The length of the wire is much short that the sensitivity is so low so to find the null point it's difficult
What about the lastest que...?
13:30 at last final question you told us to think sir but were not getting idea sir please tell sir
Am thinking that maybe because not balanced? 😂 Not sure though
well explained
Hi. I loved ur explanation. Can you please tell me how you do that animation? Even I want to do like that. Can you guide me what I have to do to learn to make animated teaching videos in physics? Your guidance will be very helpful. Please reply.
Maybe if we connect the battery the wrong way:
Pos to neg
Maybe if the polarity of the battery keeps on changing we might not get any null point. What say?
thnks sir
That's only possible if we switch the battry...
Love it
i love this but please draw some arrows
Hey you just said stay curious thats the exact line from its okay to be smart....
That isn't like a exceptional line. Many people say that
Any one knows the second scenerio
what if both these vol are not divisible by one another
❤️
why did'nt it short circuited when the reading was not 0
Practically there are some resistance
I have a question
Why does that wire that we tap from behave like a battery ( I say this because I see that as you vary the position of the Jockey along the length of the wire, the bulb either dims or increases in illumination behaving as if you were altering the voltage like the hypothetical battery you talked about at the beginning of the video). so, you vary the position of the slider, why should that have any effect on flow of current through the circuit that the bulb is connected to. You might now respond: its all about the potential difference between points on the wire. What I understand when you say that half way through the wire, the potential difference is 4.5 volts is that the battery has expended 4.5 joules of energy to get a Columb of charge to get to that position. Now , if I decide with this understanding to tap along the wire, I don't expect the light bulb's current to vary or not because I don't see how the voltage along that wire(which we tap from) will translate to having any effect on the light bulb's circuit apart from being an energy consumption value. THANK YOU.
Basically, we're not changing the voltage across bulb! Bulb neither dims nor brightens by the slider. We're just trying to reach a null point where the galvanometer shows 0 so we know that no current flows through it and the voltage across our potentiometer is exactly equal to voltage across bulb
'tadaa'😂😂
Here again, 3 years later. I still do not agree!!!😂😂😂. Stuill searching for answers, though. I'll go to Chat GPT and Gemini AI.
what do you mean?
What do you not agree with?
Can i kiss u sir i am falling in love with ur physicist brain 🫣
Your Fake accent is TERRIBLE, Speak in your own accent. Rest of the video is fine
IITian get roasted
ua-cam.com/video/HMsPnBx85dY/v-deo.html
Thank you sir!