The timestamps for the different topics covered in the video: 0:42 Introduction to Collector Feedback Bias 2:10 DC analysis of Collector Feedback Bias 5:40 Collector Feedback Bias with Emitter Resistor (DC analysis) 10:25 Solved Example For more Solved Examples on the BJT, check out this playlist: th-cam.com/video/byPBZmCfsb8/w-d-xo.html
But sir in the video explaining Q point and load line it was explained, sayin when beta increases the Q point moves up the Load line , but here it is moving downwards, can you please explain why?
Even though I already get the concepts, I still watch your videos to deepen my understanding. Thanks a lot, sir-your videos make studying more enjoyable!
Actually, a variation of only 30% to 35% in Ic or Vce arising from a doubling of β is a significant improvement in stability. If you want to improve the stability further, then simply add a resistor from base to ground, so that the collector-base feedback is through a voltage divider. That allows you to use somewhat smaller resistors for Rb1 and Rb2 which further reduces the effect of variations in β. If you're not too worried about keeping the high input impedance, then you can almost eliminate the variations due to β. It also allows you to use a smaller value for Re, increasing both the the gain and the output swing, while retaining good linearity and flat frequency response.
As I mentioned 1:15 onwards, suppose Ic increase somehow, then the voltage Voltage drop across the collector resistor will increase. Ib = Vc - 0.7 / Rb. So, Ib will reduce and hence Ic will reduce. So, due to the negative feedback, any variation in the collector current will be minimized. Basically, there is a negative feedback from the collector to the base terminal. I hope it will clear your doubt.
If you add resistor between base and ground, then during the finding base current, you need to subtract that current which is going through that additional resistor.
hi sir. i understood everything but can u do an ac analysis for this example circuit. it is quite confusing to do the ac analysis for collector feedback when the emitter resistor is not shorted.
If it is not given then you must be given some other parameter through which you can find the value. e.g Emitter voltage (VE). Or the emitter resistor won't come into the picture when it is bypassed using the bypass capacitor.
@@ALLABOUTELECTRONICS The values of voltages over BE and CE were given, and also the values of resistors Rc and Rb and value of input voltage Vcc given. How to find the value of resistor E with what was given so then I can find the values of the currents? Thank you very much.
Feedback is giving a fraction of output back to the input. In negative feedback fraction of the output is given back to the input in a such a way that it is getting subtracted from the input. The negative is used to stabilize the output.
There is a seperate video for it. Please check the BJT Playlist on the channel. You will get it. In case, if you are not able to find it, let me know here.
The timestamps for the different topics covered in the video:
0:42 Introduction to Collector Feedback Bias
2:10 DC analysis of Collector Feedback Bias
5:40 Collector Feedback Bias with Emitter Resistor (DC analysis)
10:25 Solved Example
For more Solved Examples on the BJT, check out this playlist:
th-cam.com/video/byPBZmCfsb8/w-d-xo.html
But sir in the video explaining Q point and load line it was explained, sayin when beta increases the Q point moves up the Load line , but here it is moving downwards, can you please explain why?
Even though I already get the concepts, I still watch your videos to deepen my understanding. Thanks a lot, sir-your videos make studying more enjoyable!
I fell in luv wit electronics after seeing ur videos .
Osm sir
Thank you very much for this video. This type of biasing is seldom discussed in detail. Clean and to the point. Regards.
Thanks, Sensei!
I am studing through Boylestad's book and I got stuck. Thanks!
thank you sir, your video really helps my study in digital design course.
Thank u so much 🥰🥰🥰
Your way teaching is amazing 😍
Excellent 👌 as usual 👍
Thank you for your hard work my friend.
Actually, a variation of only 30% to 35% in Ic or Vce arising from a doubling of β is a significant improvement in stability.
If you want to improve the stability further, then simply add a resistor from base to ground, so that the collector-base feedback is through a voltage divider. That allows you to use somewhat smaller resistors for Rb1 and Rb2 which further reduces the effect of variations in β. If you're not too worried about keeping the high input impedance, then you can almost eliminate the variations due to β. It also allows you to use a smaller value for Re, increasing both the the gain and the output swing, while retaining good linearity and flat frequency response.
I was looking for this comment. Can you point me to a video where this is discussed. Thanks
thank you for the video, much appreciated
Amazing video. I don't understand one thing. When we must enforce the negative feedback? Can you give me more examples?
thank you for the video but I have one question that i didn't understood the negative feedback concept in this configuration
As I mentioned 1:15 onwards, suppose Ic increase somehow, then the voltage Voltage drop across the collector resistor will increase. Ib = Vc - 0.7 / Rb.
So, Ib will reduce and hence Ic will reduce. So, due to the negative feedback, any variation in the collector current will be minimized. Basically, there is a negative feedback from the collector to the base terminal.
I hope it will clear your doubt.
thank you so much!
If there's no resistance in the collector what do I do?
Nice sir
i have a doubt. what if there is a resistor connected in between the base and ground? how will the calculation change?
If you add resistor between base and ground, then during the finding base current, you need to subtract that current which is going through that additional resistor.
Thank you sir
what is value for base voltage, VBB? Thank you.
@10:57 Should be 19.31uA.... anyways the difference it is imperceptible
hi sir. i understood everything but can u do an ac analysis for this example circuit. it is quite confusing to do the ac analysis for collector feedback when the emitter resistor is not shorted.
It is already covered. Please check the BJT playlist on the channel. You will get the related video.
Can this be solved if we don't know the value of resistor E? Thank you.
If it is not given then you must be given some other parameter through which you can find the value. e.g Emitter voltage (VE). Or the emitter resistor won't come into the picture when it is bypassed using the bypass capacitor.
@@ALLABOUTELECTRONICS The values of voltages over BE and CE were given, and also the values of resistors Rc and Rb and value of input voltage Vcc given. How to find the value of resistor E with what was given so then I can find the values of the currents? Thank you very much.
ANy video on ac equivalent model of bjt with feedback resistance?
Yes, it is there. Please check the BJT playlist, you will get it. In case, if you do not get it then let me know. Will share the link.
merci infiniment j'ai bien compris
sir what is this negative feed back
Feedback is giving a fraction of output back to the input. In negative feedback fraction of the output is given back to the input in a such a way that it is getting subtracted from the input.
The negative is used to stabilize the output.
Super bro👌
Want ac analysis of this ckt.
There is a seperate video for it. Please check the BJT Playlist on the channel. You will get it. In case, if you are not able to find it, let me know here.
Sir last line of the vdo we cant understood
Plzz remove your intro music . It is too much noisy. By the way yous concept was really noce
I'm sorry but that is the same accent as the people tat call every body up and tell them that it is the IRS that is calling them. No thank you.