The timestamps for the different topics covered in the video: 0:30 What is Current Mirror? Application of Current Mirror 2:50 Design of BJT- Current Mirror 8:45 Current Mirror with more than one transistor (N- Transistors) 10:45 Effect of base current on the Current Mirror 17:33 Improvement in the Current Mirror
Definitely one of the best videos about current mirror out there. You explained the concept very well and also discussed its practical use. I finally understand why we need current mirrors in IC and how to mirror the reference current many times without decreasing the accuracy. Great thanks!
Great explanation,it's so much crystal clear understanding of concepts..the only thing that I can wish is that may every engineering institutions will be blessed by teachers like you.. you are just awesome..♥️😊 I didn't had any concepts on ct.mirror before going through this lecture and after seeing it my concept is too clear on this topic.
At 10:50: Do the collector and base of the reference transistor need to be connected together? Why couldn't you just connect the base to Vcc via a pullup resistor?
As I mentioned in the early part of the video, if we just bias the transistor using the supply voltage and resistor, then the operating point may change with the supply voltage or temperature.
@@ALLABOUTELECTRONICS 0:55 Why does the biasing current needs to be stable to have a large Rb? I thought the point of a current mirror is that you can output a current that is the same as some reference current. Its not a current regulator that is trying to make some current stable.
Sir, at 1:07 I'm unable to understand the example of the smartphone battery you gave. If supply voltage(Vcc) is decreasing then Iref should also decrease because Iref is generated because of Vcc. So in a video why do you explain that Iref should be able to make itself constant. Please explain that part, sir.
Yes, thats true. But that's what I am saying is, it is possible to design the current source which maintains constant current even if there is a change in the supply voltage. In this video, it has not been discussed how it can be designed. But it has been assumed that, such current source Iref is readily available.
@@ALLABOUTELECTRONICS Yes sir I know that but still it's little confusing like why we are copying current in next bjt why can't we bias the 2nd bjt with any biasing technique.
@@swaritmahalsekar5521 see, the actual integrated circuit has not only one but many amplifiers. What we want is that, all the amplifier should work perfectly well even if there is any change in voltage or temperature. Of course, for that one can design Iref current source which I have mentioned in the video. But the thing is, all the amplifiers are biased at different operating point. So, if you want to run them with the special current source, then you need many such current sources with different values in the circuit. Instead of using one such special current source, the properties of that current source can be copied using the current mirror circuit and the same can be distributed to different amplifiers. I hope, it will clear your doubt.
Aren't these all current mirrors too much dependent on beta? if beta changes due to change in temp, will the circuit show significant error? To improve that do we use voltage divider CE biasing for each current mirror?
The first equation (Ic / B) is the base current of the transistor Q. The collector current is (N+1) * Ic / B. Therefore, the base current will get divided by B. And that is why the base current of transistor Q is (N+1) * Ic / B^2. I hope, it will clear your doubt.
No, in actual circuit there will be some load at the collector terminal. I mean the one end of the load is at supple and the other one is at the collector. Here just for explaining the concept of the circuit, it was not shown.
How do we get a stable current source? is Voltage divider biasing CE amplifier one of them as Ic is not too much dependent when Re is very high? Again for Current source, do we only think of DC analysis?
When we bias the transistor using the current source then collector current is equal to the current of current source.lets say it is Ibias. This Ibias is independent of beta, because that current is not generated using the base current. It's coming from some other point. So, effectively the collector current is independent of beta. I hope it will clear your doubt. If you still have any doubt, please let me know here.
@@ALLABOUTELECTRONICS If i apply current source in base then collector current is beta*base current in this way it is dependent on beta . So how can it possible to independent of beta
@@tanumoypramanik7760 You apply the current source to the collector of the amplifier. Ic and Ib are still related by beta, but Ic is held constant by the current mirror, and Ic is the important current for amplification so at that point Ib can just be whatever it ends up being.
At 10:19 and 14:29 the circuits and their areas are same..then why in 10:19 you said Ic will flow through q1,q2,q3 ??? At 14:29 you said Ic/3 will flow through each q1,q2,q3 Please clear my doubt sir!!!
At 10:04, as I mentioned, since the current through the reference transistor is equal to Iref, the collector current of all three transistors will be the same. Ic1 = IC2 = Ic3 = Iref. That means total current Ic = Ic1 + Ic2 + Ic3 = 3*Iref. With some simplification, Iref = Ic/3 . The same thing I have written at 14:35. I hope it will clear your doubt.
Very well explained. Thanks for making this video. To be emphasized for practical applications that transistor should be highly matched. VBE, hFE , Isat, Ic leakage.
Explanation is good, but please try to maintain the rhythm of your speech during the explanation and try to also write down the important points in your slide while explaining, because humans learn better by watching the important concepts and it helps in retaining it in the memory.
The timestamps for the different topics covered in the video:
0:30 What is Current Mirror? Application of Current Mirror
2:50 Design of BJT- Current Mirror
8:45 Current Mirror with more than one transistor (N- Transistors)
10:45 Effect of base current on the Current Mirror
17:33 Improvement in the Current Mirror
Practice the actual usage of "the" and this channel becomes world class.
I like .....it really,,, having teaching experience of 7 years first time I got Y actually we use current mirror thank u dear
Definitely one of the best videos about current mirror out there. You explained the concept very well and also discussed its practical use. I finally understand why we need current mirrors in IC and how to mirror the reference current many times without decreasing the accuracy. Great thanks!
Thank you very much sir 🙏
You are the only reason I am going to pass my electronics exam. Thank you for your help!
Great explanation,it's so much crystal clear understanding of concepts..the only thing that I can wish is that may every engineering institutions will be blessed by teachers like you.. you are just awesome..♥️😊 I didn't had any concepts on ct.mirror before going through this lecture and after seeing it my concept is too clear on this topic.
Classic and simple explanation....good voice.....good circuits.....and good video making.....
Simply superb sir
Cleared my concept.....thanks
An excellent breakdown. The first half was a fair bit confusing, however, namely as to what Is was, and what was meant by Is exp(Vbe/Vt).
Wonderful explanation. Thanks!!
Is it the same using PNP transistor
Top notch content and clean presentation! Would be awesome if you can make a video on the working of an induction cooker motherboard.
At 10:50: Do the collector and base of the reference transistor need to be connected together? Why couldn't you just connect the base to Vcc via a pullup resistor?
As I mentioned in the early part of the video, if we just bias the transistor using the supply voltage and resistor, then the operating point may change with the supply voltage or temperature.
@@ALLABOUTELECTRONICS 0:55 Why does the biasing current needs to be stable to have a large Rb? I thought the point of a current mirror is that you can output a current that is the same as some reference current. Its not a current regulator that is trying to make some current stable.
Sir, at 1:07 I'm unable to understand the example of the smartphone battery you gave. If supply voltage(Vcc) is decreasing then Iref should also decrease because Iref is generated because of Vcc. So in a video why do you explain that Iref should be able to make itself constant. Please explain that part, sir.
Yes, thats true. But that's what I am saying is, it is possible to design the current source which maintains constant current even if there is a change in the supply voltage. In this video, it has not been discussed how it can be designed. But it has been assumed that, such current source Iref is readily available.
@@ALLABOUTELECTRONICS
Sir can you please tell me real life example or practical application of current mirror circuits.
@@swaritmahalsekar5521 Well as I said in the videos, the current mirrors are used in all op-amps and analog integrated amplifier circuits.
@@ALLABOUTELECTRONICS Yes sir I know that but still it's little confusing like why we are copying current in next bjt why can't we bias the 2nd bjt with any biasing technique.
@@swaritmahalsekar5521 see, the actual integrated circuit has not only one but many amplifiers. What we want is that, all the amplifier should work perfectly well even if there is any change in voltage or temperature. Of course, for that one can design Iref current source which I have mentioned in the video. But the thing is, all the amplifiers are biased at different operating point. So, if you want to run them with the special current source, then you need many such current sources with different values in the circuit. Instead of using one such special current source, the properties of that current source can be copied using the current mirror circuit and the same can be distributed to different amplifiers. I hope, it will clear your doubt.
Aren't these all current mirrors too much dependent on beta? if beta changes due to change in temp, will the circuit show significant error? To improve that do we use voltage divider CE biasing for each current mirror?
I have already shown the improved circuit at the later part of the video.
gem in analog circuits
Great material as always!
You are doing a great work!! Keep blasting 🤩🤩🤩🥳🥳🥳🥳
18:32 can someone explain me how we sum op those 2 currents
The first equation (Ic / B) is the base current of the transistor Q. The collector current is (N+1) * Ic / B. Therefore, the base current will get divided by B. And that is why the base current of transistor Q is (N+1) * Ic / B^2.
I hope, it will clear your doubt.
5:05 Sir. How does current flow in an open circuit?
No, in actual circuit there will be some load at the collector terminal. I mean the one end of the load is at supple and the other one is at the collector. Here just for explaining the concept of the circuit, it was not shown.
Very nice explanation. Keep going.
Amazing session
great video ,awesome content
Your are living God man ❤️❤️❤️
Sir how that current in that
at 13:01 became 3Ic/B ?
It is the total base current of three transistors Q1, Q2, and Q3.
How do we get a stable current source? is Voltage divider biasing CE amplifier one of them as Ic is not too much dependent when Re is very high? Again for Current source, do we only think of DC analysis?
My professor took 3 lecture(around 3 hr) to explain current mirror circuit but u explained same thing in just 20 min.
Excellent explanation!!
Sir, if i use current source for biasing an amplifier how emmiter current does not depend on beta of transistor. I can not understand.
When we bias the transistor using the current source then collector current is equal to the current of current source.lets say it is Ibias. This Ibias is independent of beta, because that current is not generated using the base current. It's coming from some other point. So, effectively the collector current is independent of beta. I hope it will clear your doubt.
If you still have any doubt, please let me know here.
@@ALLABOUTELECTRONICS If i apply current source in base then collector current is beta*base current in this way it is dependent on beta . So how can it possible to independent of beta
@@tanumoypramanik7760 You apply the current source to the collector of the amplifier. Ic and Ib are still related by beta, but Ic is held constant by the current mirror, and Ic is the important current for amplification so at that point Ib can just be whatever it ends up being.
At 10:19 and 14:29 the circuits and their areas are same..then why in 10:19 you said Ic will flow through q1,q2,q3 ??? At 14:29 you said Ic/3 will flow through each q1,q2,q3
Please clear my doubt sir!!!
At 10:04, as I mentioned, since the current through the reference transistor is equal to Iref, the collector current of all three transistors will be the same. Ic1 = IC2 = Ic3 = Iref. That means total current Ic = Ic1 + Ic2 + Ic3 = 3*Iref.
With some simplification, Iref = Ic/3 .
The same thing I have written at 14:35.
I hope it will clear your doubt.
@@ALLABOUTELECTRONICS yes sir...thank you sir🙏
Cool Content....
Keep it up 👍👍👍
👌👌👌
Very well explained. Thanks for making this video.
To be emphasized for practical applications that transistor should be highly matched. VBE, hFE , Isat, Ic leakage.
Thank u very much sir , pls share practical application of it
In the beginning, I have already mentioned it.
Great video!
Very confusing. First of all, What is Vt at 3:00?
It is thermal voltage. Please go through the video of large signal model of BJT. You will get it.
Please get your basics clear first
sir, can you make a video on basic topologies of current mirror?
Really nice 👌👍
amazing content keep it up bro
Thank you 🙏
Great🔥🔥
nice lecture..
what happens if we don't short circuit B and C, why won't it work?
The current in the second transistor will not be the same as reference transistor if we do not connect base and collector
Can you do videos about Wilson, wildar and cascode current sources?
will cover some of the topologies.
@@ALLABOUTELECTRONICS okay
Widlar current source and Wilson current source
brilliant..
Not Interest 😢😢
First to comment - nice job dude. :)
no need for the intro music
nice explanation , but sorry your "english" is very hard to understood - please try to "sing" less and speak a bit "harder"
👌🏻👌🏻
Explanation is good, but please try to maintain the rhythm of your speech during the explanation and try to also write down the important points in your slide while explaining, because humans learn better by watching the important concepts and it helps in retaining it in the memory.
Please don't feel offended by my comment. Because I really love the content you people provide.
too much math
That's why they call it "engineering" instead of "Improvisation"! :-)