This man has been my messiah for Honors Algebra II, Honors Pre Calc, AP Calculus I and II, Honors and AP Chemistry, and AP Physics... I stan Thank you so much for all of your help, I am now going to Carnegie Mellon as a double major in math and computer science. I honestly think my understanding and love for math has greatly been facilitated by your videos, and I plan to use your videos for college and beyond!!
First year of undergrad to last year of it, you are literally saving my life, be it calculus, linear algebra, your explanation is unparalleled. I was struggling with this topic, i have an exam today, I almost gave up on the topic, and you explained the whole thing to me in 30 minutes. Will always be grateful to your for this quality contents.
He just helped me in calculus and now he is here again. Can you do a tutorial of revealing your face? Really appreciate what you are doing, I should ve just paid you $10,000 for tuition fee not college. My college teachers suck.
Thank you I just recently started tearing apart Old amps ect and building my own circuits ....was slightly getting confused till I watched this great explanation 👍
The class A amplifier with a resistor in the collector is inefficient because the quiescent bias current without any signal is still passing through "a RESISTOR" and so that is wasted power. Since at the collector the transistor is "a current source" one can short circuit for a DC current and that is what the inductor does, where at DC, it has no voltage across it and so it does not use any power when there is no signal, The useful current is when there is a rate of change in it and so the transformer is used to replace the collector resistor. It should have been noted that his cannot be done in the emitter as at the emitter the BJT is a voltage source and one cannot short circuit a voltage source as one can short circuit a current source. Congratulations for this video , an excellent presentation.
Great video, good explanation 👏👌 3:50 - "Vce - collector to emitter voltage should be half of collector supply voltage "? I sppose VC, collector to ground , should be half of Vcc, the supply voltage. The collector- emitter saturation voltage is typically less than 1V.
Great explanation however there is a mistake in the Class A analysis. The 25% efficiency for capacitive couple output requires a load impedance equal to the output impedance of the amplifier according to the Maximum Power Transfer theory. You have not included a load. You are correct in saying that the maximum compliance is achieved with Vce = 1/2 Vcc when there is no load. However, when a load is hooked up according to MPT compliance is maximized by making Vce = 2/3 Vcc. An ac load line is required to determine the previous statement. In theory, matching the load to the output impedance of the amplifier provides 2 equal current paths and thus wastes 50% of the efficiency across the Rc resistor. This explains why the transformer coupled amplifier can attain a theoretical maximum of 50%. In Class A mode the transistor conducts for a maximum of 180 degrees and thus wastes at minimum 50% more of the efficiency. Thus, capacitive couple efficiency is >= 50% x 50% = 25% and transformer coupled >= 50%. The extra efficiency losses are due to design problems, loss of power by other components and loss of power in because the linear region of the transistor is slightly less than 180 degrees. That is the saturation and cutoff regions are unusable.
Question: using electron flow (not "conventional current"), looking at the Class B amp at 9:44, the positive going input signal will turn on Q1, which will cause electrons to flow from the ground, through RL, "through" the output capacitor, up through the emitter and collector of Q1, to Vcc. When this is happening Q2 is turned. After this happens (and the input signal goes back to zero), the output capacitor is charged with a positive on the side that goes to the emitters, and a negative (electrons stored) in the side that is connected to the load resistor. When the input signal changes, and goes negative, Q2 turns on and Q1 shuts off. This makes the resistance across the emitter and collector, of Q1, very high (very little current flow through Q1.) As Q2 begins to have electrons flow through it from the ground, up through the collector then through the emitter, the electrons are "pulled" by the positive charge on the capacitor (the plate connected to the emitters,) and electons will flow into the plate of the capacitor that is attached to the emitter of Q1, while the other side of the capacitor (the other plate) will send it's electrons down to ground, through RL. Correctamundo?
Amazing! You're good at this. (I mean the explanations) Many try, few succeed. I saw this exact formula (for Ib) on another video and was a little perplexed. Now, much clearer. Thanks!
Always more to learn lol : D ... Questions With the class C could not one place a resistor at the ‘E’ which would mean that the voltage drop across this would mean that the junction between the E and the resistor will have some voltage in ref to ‘ground’ example 1v , this would then mean the E has 1v ref above the Base if the base is ref to ‘ground’ Another question, could you trace the ‘current flow’ in a basic AB amplifier for amusement and insanity? The only way this device can function {for me} is if the ‘N’ junction is equalized to the ‘P’ junction when they are merged , I.e they effectively became one device with two junctions and a equalized 0 central point that is because the N from the NP>N equalizes with the ‘P’ of the P
WTH...... I was literally searching for informations about audio amplifier on UA-cam and I know you because I used to watch a lot of video from you to help my high school study (like physics and maths) but MAN you literally know everything OH MY GOD ?! you not only shocked but also scared me XD you are amazing, how can you literally know everything ??? man you must have lots of degree OMG XD
1:31 "coopling capacitors" ?? They are 'coupling' capacitors. ie. They 'couple' the AC signal from the previous stage to the next stage. They don't "cooople"
Probably you should mention something about DC biasing and superimposing the A/C signal so that it oscillate around Vb. For example offset 0.2V A/C by 0.8 DC so that compound signal oscillates around 0.7-0.9V
Did he call the capacitors and transformers of the Class A Amplifier 'coupling capacitors'? His pronunciation is unfamiliar. Also I'm experiencing trouble making this circuit work in the app iCircuit. Anyone familiar with it. How do I set the elements of Vcc ? Also, I'm very hazy about the logic and strategy for how these circuits are designed. Nice that he clarified that current can't flow in reverse across the emitter of the transistor.
Hye, may I ask? How is the working for Class A amplifier without AC input? Now I am doing a mini project, the title is Audio Amplifier for Cell Phone (Class A). Can you help me?
Coupling is pronounced "cupling". I've seen many class AB amps that do not use diodes. The class C amp is used in high level AM final amplifier in transmitters.
Great video. But a opportunity lost. Should explain it effects on audio and rf. Reproduction of A class amplifier is near perfect reproduction of input. The best. Effieciency is 4000w in 1000w out. Fot rf it is class A , AB (SSB) and C(CW FM) that is always used for comms. 👍👍👍👍waiting for next video.
It's a great explanation, but you didn't show where the speaker + and - should be, also the + and - for input and output. Beginner like me would have difficulties understanding them.
Can someone explain to me why he puts a negative voltage supply there. I'm new to electronics so I don't know. I just think it's because some positive voltage goes left instead of to base. This means some of that extra positive voltage needs to be cancelled out by going to a negative source.
None of videos out there regarding class ab single supply's voltage will explain what makes each transistor on and off for base of each transistor is always 0.7 greater than the emmiters of both transistor for 360° of input signal(emmitter follower concept). So how???? Help me out
At time 5:30: "...transformer *_C O O P U L L E D_* class A amplifier...." "COOPULLED" - it's supposed to say COUPLED. Not COOOOOO - PULLED I point this out because - apparently, this voice IS SYNTHETIC! They did a really good job with the volume inflections for the words, and for the cadence. This one little error - saying "cooo - pulled" instead of "COUPLED" - was the giveaway. Remarkable how high the quality of this synthetic voice is. The error in the software that creates this voice is easy to fix (I'm a software engineer). Right now, the mistake being made is this: "coupe" is a type of car. It's pronounced "COOP" And the -led suffix is used everywhere: "STUMBLED", "MUMBLED", "TUMBLED", and is pronounced "ULL'D" So the software is mistakenly combining "Coupe" with "ull'd" and pronouncing it "cooo-pulled" I can't believe how good the voice is. I was 100% convinced it was the author of the video speaking.
If you're going to talk about the different classes of operation then the first thing you should do is explain what the differences are, i.e. class A conducts over the full swing of the input, B over just +ve or -ve swing, etc, rather drawing a common emitter amp, complete with bias feedback, and saying 'this is a class A amp'. There are other ways of implementing class A.
The voltage divider constantly supplies 0.7 V (dc) to the base. This is to just open the transistor. If any (positive) input voltage is added, base current increases accordingly, so there are no distorsions at the output. If there is no voltage divider at the base, you will have pure input signal that opens the base. The problem is that the base opens only if input signal is higher than 0.7 V. So, everything below 0.7 V that comes from the input signal source is simply lost. This causes distorsion of the output. The remedy is this voltage divider that you asked about.
Class a has a sound that is better than the others. I'm not too worried about efficiency but I am in sound quality. You need some larger transistors like a tip122 and use lower voltage like 5 v 1a to power them. Less resistors and no voltage divide just place a 1k resistor or pot between the base and collector for biasing and bam nice little amplifier
Base resistor must be connected between vcc and base terminal..not between base and emitter. Class B amplifier shown should be called Class B push pull.
Final Exams and Video Playlists: www.video-tutor.net/
Why class b are not loud sound? I make it and I tested not loud what's wrong my make
I increase a voltage and amps and same sound not loud?
This man has been my messiah for Honors Algebra II, Honors Pre Calc, AP Calculus I and II, Honors and AP Chemistry, and AP Physics... I stan
Thank you so much for all of your help, I am now going to Carnegie Mellon as a double major in math and computer science. I honestly think my understanding and love for math has greatly been facilitated by your videos, and I plan to use your videos for college and beyond!!
@the noah lucario best of luck man! if you're using OCT I'm sure you'll do great
How are your studies going?
There is like magic in your voice and explanations, they are clear, precise and the essential is said to allow us to always learn something. THANKS.
First year of undergrad to last year of it, you are literally saving my life, be it calculus, linear algebra, your explanation is unparalleled. I was struggling with this topic, i have an exam today, I almost gave up on the topic, and you explained the whole thing to me in 30 minutes. Will always be grateful to your for this quality contents.
0:17 - Class 'A' amplifier
7:59 - Class 'B" amplifier
11:45 - Class 'AB' amplifier
13:10 - Class 'C' amplifier
He just helped me in calculus and now he is here again. Can you do a tutorial of revealing your face? Really appreciate what you are doing, I should ve just paid you $10,000 for tuition fee not college. My college teachers suck.
instablaster...
Wow, you make this stuff seem as easy as A…B…C…. Keep up the great work!
Nice video. NPN -Not Pointing iNward. PNP - Perfectly iNward Pointing.
PNP - Pointing neutral Point, NPN -Not Pointing Neutral
Ever since we went to online classes cause of the quarantine. You’ve helped me a lot. Thanks!
Thank you I just recently started tearing apart
Old amps ect and building my own circuits ....was slightly getting confused till I watched this great explanation 👍
Just what I was looking for to assign my class this week. Your presentation is excellent.
The class A amplifier with a resistor in the collector is inefficient because the quiescent bias current without any signal is still passing through "a RESISTOR" and so that is wasted power.
Since at the collector the transistor is "a current source" one can short circuit for a DC current and that is what the inductor does, where at DC, it has no voltage across it and so it does not use any power when there is no signal, The useful current is when there is a rate of change in it and so the transformer is used to replace the collector resistor.
It should have been noted that his cannot be done in the emitter as at the emitter the BJT is a voltage source and one cannot short circuit a voltage source as one can short circuit a current source.
Congratulations for this video , an excellent presentation.
That one clear, detailed and overall good explanation. Thank u.
9:55 +cycle Vs -cycle. Great job. Good and clear explanation. 😇😇😇👍👍👍🙏🙏🙏
I usually go to these videos to help me with my algebra class.
I'm going to comeback to this video 3 years later when I'm finished with college, wish me luck!
Great video, good explanation 👏👌
3:50 - "Vce - collector to emitter voltage should be half of collector supply voltage "? I sppose VC, collector to ground , should be half of Vcc, the supply voltage.
The collector- emitter saturation voltage is typically less than 1V.
lol I like how he says "coopled"
@@AndysRamblings Lol nah it's mostly an isolated quirk of pronunciation nothing wrong with the video
@@AndysRamblings wouldn't want to do that
this man helped me get my distinctions😩
Great explanation however there is a mistake in the Class A analysis. The 25% efficiency for capacitive couple output requires a load impedance equal to the output impedance of the amplifier according to the Maximum Power Transfer theory. You have not included a load. You are correct in saying that the maximum compliance is achieved with Vce = 1/2 Vcc when there is no load. However, when a load is hooked up according to MPT compliance is maximized by making Vce = 2/3 Vcc. An ac load line is required to determine the previous statement. In theory, matching the load to the output impedance of the amplifier provides 2 equal current paths and thus wastes 50% of the efficiency across the Rc resistor. This explains why the transformer coupled amplifier can attain a theoretical maximum of 50%. In Class A mode the transistor conducts for a maximum of 180 degrees and thus wastes at minimum 50% more of the efficiency. Thus, capacitive couple efficiency is >= 50% x 50% = 25% and transformer coupled >= 50%. The extra efficiency losses are due to design problems, loss of power by other components and loss of power in because the linear region of the transistor is slightly less than 180 degrees. That is the saturation and cutoff regions are unusable.
Question: using electron flow (not "conventional current"), looking at the Class B amp at 9:44, the positive going input signal will turn on Q1, which will cause electrons to flow from the ground, through RL, "through" the output capacitor, up through the emitter and collector of Q1, to Vcc. When this is happening Q2 is turned. After this happens (and the input signal goes back to zero), the output capacitor is charged with a positive on the side that goes to the emitters, and a negative (electrons stored) in the side that is connected to the load resistor. When the input signal changes, and goes negative, Q2 turns on and Q1 shuts off. This makes the resistance across the emitter and collector, of Q1, very high (very little current flow through Q1.) As Q2 begins to have electrons flow through it from the ground, up through the collector then through the emitter, the electrons are "pulled" by the positive charge on the capacitor (the plate connected to the emitters,) and electons will flow into the plate of the capacitor that is attached to the emitter of Q1, while the other side of the capacitor (the other plate) will send it's electrons down to ground, through RL. Correctamundo?
I learned more knowledge from this in 17 minutes compared to the 5 hours lecture in my uni
Thanks
It's easy ti understand now than in lectures
You are just brilliant and know very well how to explain with so ease, claps buddy!
This guy knows about everything.
Amazing! You're good at this. (I mean the explanations) Many try, few succeed. I saw this exact formula (for Ib) on another video and was a little perplexed. Now, much clearer. Thanks!
Always more to learn lol : D
...
Questions
With the class C could not one place a resistor at the ‘E’ which would mean that the voltage drop across this would mean that the junction between the E and the resistor will have some voltage in ref to ‘ground’ example 1v , this would then mean the E has 1v ref above the Base if the base is ref to ‘ground’
Another question, could you trace the ‘current flow’ in a basic AB amplifier for amusement and insanity?
The only way this device can function {for me} is if the ‘N’ junction is equalized to the ‘P’ junction when they are merged , I.e they effectively became one device with two junctions and a equalized 0 central point that is because the N from the NP>N equalizes with the ‘P’ of the P
You explain the HOW good, but rarely the WHY.
No kidding, you're a literal life saver
WTH...... I was literally searching for informations about audio amplifier on UA-cam and I know you because I used to watch a lot of video from you to help my high school study (like physics and maths) but MAN you literally know everything OH MY GOD ?! you not only shocked but also scared me XD you are amazing, how can you literally know everything ??? man you must have lots of degree OMG XD
Organic chemistry has really changed since I was in school.
You sir are a SAVIOUR thank you SO MUCCCH!
"coopling capacitor" lol
good and informative video though, thanks
I also noticed that he pronounces couple as coople. I wonder if his pronunciation is due to some regional accent? Curious.
Say coople... one more time..
1:31 "coopling capacitors" ?? They are 'coupling' capacitors. ie. They 'couple' the AC signal from the previous stage to the next stage. They don't "cooople"
Most of the capacitors couple. But HIS capacitors cooople. Pls, do not argue with capacitors, they know better what they do.
Probably you should mention something about DC biasing and superimposing the A/C signal so that it oscillate around Vb. For example offset 0.2V A/C by 0.8 DC so that compound signal oscillates around 0.7-0.9V
How u have knowledge of every field 😯
Did he call the capacitors and transformers of the Class A Amplifier 'coupling capacitors'? His pronunciation is unfamiliar. Also I'm experiencing trouble making this circuit work in the app iCircuit. Anyone familiar with it. How do I set the elements of Vcc ? Also, I'm very hazy about the logic and strategy for how these circuits are designed. Nice that he clarified that current can't flow in reverse across the emitter of the transistor.
This guy is the entire university.
Thank from Tanzania
Hye, may I ask? How is the working for Class A amplifier without AC input? Now I am doing a mini project, the title is Audio Amplifier for Cell Phone (Class A).
Can you help me?
Can you pls upload a video in AB and B amplifiers circuit analysis. I have a test coming in a day.
Amazing video 👏
9:44 Any reason a single coupling capacitor couldn't have been used directly past the ac source, and then split off to the two bases?
Coupling is pronounced "cupling". I've seen many class AB amps that do not use diodes. The class C amp is used in high level AM final amplifier in transmitters.
great video. can anyone tell me what software is he using to draw
1:30 am. Today morning is Electronics exam & I'm watching this ...
Like if ur doing the same 😉😉👍🏻
Good Job
this guy is smart, i swear he knows everything maths/ science/ engineering based ahaha
Great video. But a opportunity lost. Should explain it effects on audio and rf. Reproduction of A class amplifier is near perfect reproduction of input. The best. Effieciency is 4000w in 1000w out. Fot rf it is class A , AB (SSB) and C(CW FM) that is always used for comms. 👍👍👍👍waiting for next video.
Thank you
I bet you could replace the diodes with transistors whose base and collector are coupled, on the class B.
FOR CLASS A AMPLIFIRE WHAT YOUR REREFERANCE FOR PSU SMPS OR TRFO?
Would have been good to explain the biasing on the B and AB.
is this small signal or large signal amplifier? and can I use this method to make a audio amplifier(loud speaker)?
Great Video
Coopled?..why is c1's polarity different than c2?
Which Guitar Amp belongs to the Class type?
and which the 88key keyboard Amplifier belongs to the class type?
It's a great explanation, but you didn't show where the speaker + and - should be, also the + and - for input and output. Beginner like me would have difficulties understanding them.
Thank you.From Türkey 🇹🇷
How about the efficiency, if we put transformer instead rc in the output
What college did you graduate?
Since the class A and Class C are off for negative cycle, does it not half the data could be lost?
Awesome 👏 Your voice is sweet
Amazing and super
Hi .is it pussible to amplify a fast edge squre wave (rise time=30ns) with 10 Vp-p to 100 Vp-p and with rise time being less than 60ns?
Nice and cool voice
Can someone explain to me why he puts a negative voltage supply there. I'm new to electronics so I don't know. I just think it's because some positive voltage goes left instead of to base. This means some of that extra positive voltage needs to be cancelled out by going to a negative source.
whats the function of RB on the last 2 circuits?
Which class of amplifier design has lower THD or sound clear or best ? kindly enlighten me ty
AB
How if we introduce 2diodes how we can reduce the crossover distortion can you explain still
May I ask whether transistor amplifiers different from power amplifier? I found some circuits in the Internet and it has small differences
What tool is used to draw on screen?
None of videos out there regarding class ab single supply's voltage will explain what makes each transistor on and off for base of each transistor is always 0.7 greater than the emmiters of both transistor for 360° of input signal(emmitter follower concept). So how???? Help me out
At time 5:30: "...transformer *_C O O P U L L E D_* class A amplifier...."
"COOPULLED" - it's supposed to say COUPLED.
Not COOOOOO - PULLED
I point this out because - apparently, this voice IS SYNTHETIC! They did a really good job with the volume inflections for the words, and for the cadence. This one little error - saying "cooo - pulled" instead of "COUPLED" - was the giveaway.
Remarkable how high the quality of this synthetic voice is.
The error in the software that creates this voice is easy to fix (I'm a software engineer). Right now, the mistake being made is this:
"coupe" is a type of car. It's pronounced "COOP"
And the -led suffix is used everywhere: "STUMBLED", "MUMBLED", "TUMBLED", and is pronounced "ULL'D"
So the software is mistakenly combining "Coupe" with "ull'd" and pronouncing it "cooo-pulled"
I can't believe how good the voice is. I was 100% convinced it was the author of the video speaking.
With 2'12" left you draw the polarity of signal generator wrongly to put the transistor in cut off!
Can someone please explain what RB and R1 does.
Ah, it says on Razavi's RF Microelectronics Class A has a max effect of 50 %. Why is that?
how do you know like, everything from chemistry to electronics to psysics and everything
If you're going to talk about the different classes of operation then the first thing you should do is explain what the differences are, i.e. class A conducts over the full swing of the input, B over just +ve or -ve swing, etc, rather drawing a common emitter amp, complete with bias feedback, and saying 'this is a class A amp'. There are other ways of implementing class A.
Nice!
How have an amplifier with (Vs/Ve) = 1000 ?
JG please teach about "host guest" & clatharates in organic chemistry
rB in the last ckt?
What is mean by voltage divider and its use
The voltage divider constantly supplies 0.7 V (dc) to the base. This is to just open the transistor. If any (positive) input voltage is added, base current increases accordingly, so there are no distorsions at the output. If there is no voltage divider at the base, you will have pure input signal that opens the base. The problem is that the base opens only if input signal is higher than 0.7 V. So, everything below 0.7 V that comes from the input signal source is simply lost. This causes distorsion of the output. The remedy is this voltage divider that you asked about.
How did you know what I was thinking, dawg!?
Class a has a sound that is better than the others. I'm not too worried about efficiency but I am in sound quality. You need some larger transistors like a tip122 and use lower voltage like 5 v 1a to power them. Less resistors and no voltage divide just place a 1k resistor or pot between the base and collector for biasing and bam nice little amplifier
i don't know how you do it man😁😁
Are you mark wahlburg?
This guy from the east coast?
My next inclination would be to ask what an ABC amplifier looks like? lol , {I wish I was joking : D }
I thought it's organic chemistry but nvm I'll digest it
Berapa nilai resistansi resistor
hello tupvian
Coopled
bro how are you so smart
Your NPN let’s ground flow, now positive. Yet your diagrams are showing npn connected to VCC. Unreal…
None of these videos explain how a signal flows through an amplifier and what happens...Pretty disappointed
😊 🎉
Base resistor must be connected between vcc and base terminal..not between base and emitter. Class B amplifier shown should be called Class B push pull.
Is there anything this man doesn't know?????
Interesting but stop saying coopled, its coupled as in married couple.
🤓☝🏻
Can you discuss a active tone control circuit.
😂😂
Bet you are fun at parties
I guess you will just have to coop with it.