Common Collector Amplifier
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- Опубліковано 23 лип 2024
- A tutorial on how to do the AC analysis of a common collector amplifier. In other words, if you are shown a common collector amplifier circuit, this video will help you to figure out, via analyis, the voltage gain, the input impedance and the output impedance of the circuit.
It is nice that you left numbers out, which confuse things. Your explanation of the math was very understandable.
Frank
Frank Reiser Video/Audio Service
Caldwell, NJ
Thank You, Sir, your videos have helped me a lot to understand the fundamentals of electronics very clearly. I see you as my teacher.
The best my friend. I have watched many of these tutorials. Yours is certainly up there in clarity, pace, and complete explanations for the beginner to be able to understand. Just what I needed.
Thank you so much David Williams! I learned a lot! At BCIT for Robotics with Maurice LeNoble, Im glad you made these videos these were amazing study aids!
Thanks for a clear presentation for calculating DC and AC voltage.
Thank you very much for a useful lesson!
Great video. Helped me a lot.
Awesome!!! thank you for uploading this video, It really helped me a lot!!
great lesson. thank you so much.
awesome lectures sir....thanks
@okami11408 For common collector, you just don't need one. Look at the derivation of input impedance, output impedance and voltage gain, and you'll see that the collector is not part of the derivation. You could put in an RC if you wanted to, it would change the DC operating point without affecting the AC parameters much.
kudos, tnx ur a great help
YOU ARE AMAZING. PLEASE MAKE MORE VIDEOS FOR ELECTRICAL ENGINEERING COURSES.
Great video thanks
Bcoz of this video I'm subscring to our channel.an excellent explanation
Best explanation on the web, there seems to be different lines of thought when calculating CC output resistance. Specificly what to do with v in and its source resistance. A few instructors claim that shorting out v in includes shorting out its source resistance. Others don't address the source resistance at all. Can this circuit be calculated in open circuit mode then proceeding to the amp model to calculated overall gain?
Thank you Sir, really thank you
hello sir, i read that to avoid loading effect we need to have low ouput impedance for source and high input impedance for load to transfer maximum power to load.can i know by what order it should be greater for better transfer of power in design prespective. and does it mean that by having low ouput impedance most of the current will pass through load?? thank u
you are the best!
With any amplifier, you are going to drive some sort of load (e.g., RL) by applying an output voltage across it (Vout)...in other words Vout is applied across RL
When calculating Vb to determine Zoutb, can I just use the result I got from DC analysis (Vb = Vcc - IbRb)?
Yes, If he uses capitals it shows a DC variable, all small signals are shown in lower case.
sir I want to perform dc analysis of cc amplifier
Thanks sir nice video thnks and I love you
wouldn't Re also add to the voltage drop?
VERY THANKS BROTHER
how to find current gain in the same ciruit?
I love you man
Sir...why can't we measure Vin across Rb and how can we select Vin in this case where there was a current source between positive and negative terminal of voltage...
Why isn't the RL before Vout in the small signal analysis? Thank you for your videos =) I hope you'll get to do more advance subjects as well
Question:
when doing Ac analysis, I assumed you used T model ? If you did, why did you connect Beta_ib differently, while in Common emitter amp video you used Beta_ib on the different location.
I did use the T model for the BJT and while I did draw Beta_ib in a different location on the page, I did indicate that I still drew it on the collector...I just swapped the positions of the collector and emitter.
thanks!!!
should not the current source be connected between the collector and the emittor not the base?
Good video, but there is a small mistake. In 16:39 it is said you can disconnect the current source, but you can't do that because that current source is a *current controlled* current source, and you're not allowed to short circuit or disconnect controlled sources, but only to remove fixed sources.
how do you calculate the quiescent collector current for the common collector amplifier
see: ua-cam.com/video/LDgUgzNrsqU/v-deo.html
@David Williams: Since when Zin considers load resistance in its equation?
For the common collector, load resistance is "seen" when looking in to the circuit, so it has to be considered in the Zin calculation. Another way to put it, when you apply a test voltage at the input, the resulting current will change if the load resistance changes. Since test voltage over resulting current is input impedance, Zin depends on the load resistance.
Does this apply only for common collector? Because common emitter is drawn almost the same way except output is taken from the emitter.
Right, common emitter is not affected by the load because the output at the emitter is not seen from the base
When you say "seen from", you are referring to circuit equivalent small-signal model?
why there's no collector resistor?
Dear David,
Thank you very much for the great lesson, I understand this circuit a lot better now. I just have one thing I'm not clear on: What actually is Zin? I understand all the algebra to find the impedance at this point of a circuit, but what I don't understand is that there's not actually a resistor here. I don't understand conceptually what this resistance/impedance is.
Any help on this would be very much appreciated.
Tim
+Timothy Olsen Zin is the input impedance which is the impedance (resistance) that the amplifier presents to a source that is connected to it.
+David Williams Thanks for the answer. Are you saying that the input to the amplifier has a general impedance (measured at the base) as well as the impedance measured across RB?Tim
+Timothy Olsen that's correct, but the two impedances need to be taken together to give the input impedance of the whole amplifier as seen from the source.
+David Williams I understand it now. thanks
Input impedance means if you apply a certain voltage, what will be the current flowing into the amplifier..And since power =VxI, it will tell you power too..
should Re be out because we shorted the capacitor !?
No, shorted means taking out the cap and putting in a wire.
NIce vid, amazing. But I am getting high pitched hisses everytime you say sssssss.
Why don't we have current gain in common collector amplifier
CC amps do have current gain (Ai) which is going to be approximately equal to beta of the BJT
Why is it called amplifier? What is it amplifying?
Current....I think.
Why is the 're' and 'ic' in opposite places in the emitter amplifier and the collector amplifier? Is it a mistake or is their a reason? Also Thanks, these are great videos :)
wouldn't we have a voltage drop across Rs?
Dear brother ,I have doubt please help,
when we calculate voltage gain without include source and load resister, we can write Av= vout/vin=ie.RE/vb=Ie.RE/Ib.RB=(B+1)RE/RB.
PLEASE REPLY IS IT CORRECT OR NOT.
Q/ If RB increase two double of its value the what will be effect on voltage gain?
If I conquer the world, you are to blame
What about common base? You skipped one?
You like math too much, you're not doing electronic here but mathematics
Electronics is physics and math! He's deriving the important equations that are used extensively when designing common collector amplifiers!
sir I want to perform dc analysis of cc amplifier
sir I want to perform dc analysis of cc amplifier