BJT- Current Mirror Explained

In this video, what is the current Mirror, why it is used, and how it can be designed using the BJT (Bipolar Current Mirror ) is explained in detail.
And in the end, how the performance of the Bipolar current mirror can be improved is also explained.

By watching this video, you will learn the following topics:

0:00 Introduction

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

What is Current Mirror:

The current mirror is an analog circuit that senses the reference current and generates the copy or number of copies of the reference current, with the same characteristics.

The replicated current is as stable as the reference current source.
The replicated current could be the same as the reference current (Icopy = Iref), or it could be either multiple or fraction of the reference current. (Icopy = N*Iref or Icopy = (1/N)*Iref)
In the video, how to generate the multiple or the fraction of the reference current is explained in detail.

Why Current Mirrors are used?

Current Mirrors are particularly useful in the integrated circuits, for biasing the amplifiers.
In integrated circuits, one stable current source is fabricated within IC, and using the current mirror the multiple copies of the stable current source is generated (which can be used to bias the amplifiers)

Effect of Base current in the Current Mirror Analysis:

In this video, During the initial analysis of the current mirror, it has been assumed that the base current is negligible. (Ib = 0)
But that is not the case, in the actual circuits.
With the non-zero base current, there will be some errors in the earlier approximation.
This error can be minimized using the improvement in the current mirror circuit.
At the end of the video, the improved current mirror circuit is discussed.

The examples on the current mirror will be solved @ALL ABOUT ELECTRONICS- Quiz

This video will be helpful to all the students of science and engineering in understanding what is a current mirror, and how it can be designed using the BJT.

#CurrentMirror
#BipolarCurrentMirror

--------------------------------------------------------------------------------------------------
Follow me on Youtube:

Follow me on Facebook:

Follow me on Instagram:
--------------------------------------------------------------------------------------------------

[ALLABOUTELECTRONICS]

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

[thaiphan]

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!

[electronicslecturesbygulsh]

I like really, , , having teaching experience of 7 years first time I got Y actually we use current mirror thank u dear

[TheRandomShow]

You are the only reason I am going to pass my electronics exam. Thank you for your help!

[sankhamitra]

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.

[rmohand.v]

Classic and simple explanation....good good video

[snehadeepbhowmick]

Top notch content and clean presentation! Would be awesome if you can make a video on the working of an induction cooker motherboard.

[loltwest]

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).

[abcddd]

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?

[swaritmahalsekar]

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.

[farhanupaul]

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?

[farhanupaul]

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?

[madeinandhra_]

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!!!

[mohammedhashmathullah]

You are doing a great work!! Keep blasting 🤩🤩🤩🥳🥳🥳🥳

[tatvamkrishnam]

5:05 Sir. How does current flow in an open circuit?

[darnavik]

Sir how that current in that
at 13:01 became 3Ic/B ?

[gaurabthapa]

anybody please provide link of current steering of bjt

[yogeshraj]

My professor took 3 lecture(around 3 hr) to explain current mirror circuit but u explained same thing in just 20 min.

[Kalman]

18:32 can someone explain me how we sum op those 2 currents

[topquark]

Very confusing. First of all, What is Vt at 3:00?