One of the best tutorial on transistor amplification I have seen on RU-vid. It is so clean and simple with fantastic narration. Just wonderful! Thanks for your efforts, much appreciated.
beautiful tutorial lesson on how PNP and NPN transistors can be put in cascade together to get a very high amplification at the end of the cascade.thanks for the very special lesson. You should bring some more of the theoretical way to explain other amplification stages like the output stage of an amplifier for guitar, for example.thank you.
Finally, a simple design to get me started with good clear instructions on how it works. Up until now I was a Transistor Cave Man. I would try and build something but end up like The Hulk and "Hulk Smash" when it didn't work.
Really appreciate slow and thoughtful explanations! there are a lot of different hurdles just understand why these circuits work… So I’m still struggling and appreciate the lesson!
Great video. I hope you continue to do these basic circuit vids. Would also be really nice to see these set up on a breadboard to. Either way they are very enjoyable.
After I had uploaded the video I realized I forgot to show the circuit on the breadboard. You really can't see much on the breadboard but it is reassuring to see that I actually built the circuit.
Very beautifull ! In addition to the great educational content, I love these videos because they are explained with patience and slow talk. I am Italian and these videos are very understandable! Intelligent and brilliant author!
noob question: at the end of video with two stage amp, if left amp is out of phase 180 and right amp is out 180 then why doesn't the final (green) signal show up as in phase with original signal generator? I thought it would keep shifting the time base of signal. thanks
Yes it is not perfect. It may be due to the 0.03uF capacitors not being exactly equal, the beta of each transistor not being exactly equal, also it has been a while since I calibrated the scope probes, or all the above. It looks like the phase shift is just a few degrees out. I purposely left it that way because it is very hard to get things absolutely perfect, like in a book.
That's great, thank you. I suppose npn and pnp pair is necessary to cancel the inversion. If both are inverting the signal, why can't we do it with 2 npn stages?
The bases of a NPN and PNP are 180 degrees out of phase. This what makes the Push Pull work. This video may help. MOSFET Push Pull Amplifier Visual Demo ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE--6N7l1dnk6s.html
Is a software scope being used here? In all cases, the image shows the input and output signals at something other than 180 degrees or in phase...it is quite noticeable. Might cause some confusion since the visuals don't show quite what the narration says.
Sir, I was experimenting with this circuit and my sine wave coming out of the first stage was clipping on the top part of the wave. I was using a 1kh sine wave using the resistors in you diagram. My transistors were bc547 and bc557. Can you advise me as to what I can do to correct this. I am a novice . Thank you
Let's just talk about the NPN transistor bc547. When your signal at the output is clipping at the top that means the base of the NPN transistor is to positive. You could lower the 10K resistor, but I don't recommend that because you may start to short out the signal you're trying to amplify. I would raise the resistance of the 100K resistor, 5K, 10K, 20K,,,. Whatever voltage you are using VDC to drive the circuit, it should measure about half VDC from the collector of the transistor to ground. When you achieve these results the output should be a nice sine wave. If you have the biasing just about perfect, and you overdrive the circuit the top and bottom should clip at about the same time. All this is the same for the PNP transistor bc557. Just reverse the polarity of everything.
this is good for the practical connection and show what will be displayed on screen. i have learned 3 months for BJT and i know i am still a beginner as yr tittle. i can learn something new on it especially the connection of 2 BJT
You stated that the 470 ohm resistor is for self bias and the 100K and 10K are for fixed bias. Does the transistor need both for bias? Can it operate normally with just fixed bias?
Yes this circuit needs both. It's designed for the beginner to have a successful working circuit. Build it and make some changes in the biasing and see what happens to the output signal.
AllAmericanFiveRadio thanks I've seen the video, but since I don't own an oscilloscope I can't do it empirically like you do, I need to do calculations on paper to get the resistor's and caps values to optimize output.
The first thing to determine is, what is it you want to build. Let's say it is class A amplifier. The load the transistor is driving will have a great influence on the biasing. Also we would need to know what is the voltage you're going to use. For class A operation grounded emitter circuit the collector should have a value about half the output of the power supply. This can be checked with a volt-ohmmeter. The biasing resistors for the base must be chosen to produce this result, but it's more complicated than that. There are many combinations of resistors that could produce class A biasing. What determines the choices for these resistors is the signal that is going to drive the base. If you choose bias resistors that are too low you may short out the signal you are trying to amplified. I would start with the datasheet for the transistor you want to use. Usually manufacturers will supply biasing information along with test circuits that you can modify for your purpose.
Great video as always! I wonder though, while both of these cascaded circuits are exactly identical, the amplitude is still at all greater throughout the second stage. This means more current draw on through the load. In practice, we see the transistors and passive biasing equipment increase in wattage, as we move up the stages. So my question is: Should we simply go for a larger transistor whenever our current (amplitude voltage times impedance of the load) exceeds what the transistor can tolerate, or should clipping be taken into account as well in this case? B.R. -Ragnar
You actually worked backwards. Let's say the last stage is going to be driving a device that can draw 1 AMP. I would choose transistors that could handle at least 2 AMPs in the last stage.
Thank you, and your welcome. For the drawings I use FreeHand or Corel Draw. After I have the drawing I make them into cells using Photo Shop Elements. Then I take the completed cells and animate them with Photo Shop Premiere Elements.
Great video! Thanks for this! I like how you show the input and outputs oscilloscope. Did you know your Audio is slightly bass heavy? Just something I noticed! Not big a issue or anything. 😀
These videos may help you. Transistor, How Does it Work in a Circuit, Demo ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-vs3zUHdlsYY.html Transistor How can it Amplify ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-O9aT950DRkw.html Transistor What does it do in a circuit Visual Demo ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-o1ygTZTHDnE.html NPN Transistor on off switch and also a variable resistor ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-knm_t10hJGM.html Junction Transistor for the Beginner, the basics ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-pStpu8DslXo.html Determining NPN PNP C E B for a Junction Transistor using a Ohmmeter ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-fWBjvaRDErk.html Transistor Basic Function ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-BOMbydWGecg.html
Sir I have a led blincker cuircut that produce 15 hz wave but it's voltage very low around 2-5 volt and amp is also low but I want around 50v and 1-2 amp for my project can I use this cuircut for it please reply me
You may be able to use a relay or just the IGBT. Auto ON OFF Circuit Updated with IGBT ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-n-Ac4czBkpM.html 180° Phase Shift using one IGBT Auto ON OFF Circuit ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-KwS1f3Z1150.html
Hi i made a common emmiter amplifier for 200mhz signal with 2× gain I can amplify a 50 mv p-p to 100mv p-p but I can't do it for 2v to 4v p-p Why what values should be change???
thanks for reply. 2:53 what i see is that the right edge of yellow wave is overlapped with green wave while there is less or no overlap of the left side of yellow wave. therefore i say it looks not exactly 180 degree phase difference. thanks
Hope this answers question. Audio Phasing, Important and Useful ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-lgWLCG5vg5c.html Amplifier Input and Output Phasing ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-m7X2XfUmnro.html Transformers, basic phasing ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-BRBqUQPLk-M.html
Biasing an Audio Transistor ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-KtXE7s5DlcI.html Biasing Basics, Class A ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Mah6TXRBXHs.html Build a Two Transistor Audio Amplifier ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-H_ybgHLKe6w.html Transistor Amplification Factor, Beta ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-Bk5H2DjL3a0.html Transistor What does it do in a circuit Visual Demo ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-o1ygTZTHDnE.html Control Grid, Triode Tube ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-K_AJRIsNlR0.html Searching My AllAmericanFiveRadio Channel ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-4k7ByHqh8Js.html
I use Freehand 11 for the drawings, Movavi to screen capture the Oscope, Adobe\Photoshop Elements 2018 to put all the drawings in order and size them, and Adobe Premiere Elements 2018 to make the video.
how are you powering this circuit? I notice that on the pnp transistor the positive is grounded. I was bread boarding this circuit but had to stop because I didn't understand the power supply. Thanks
I think if you know how a audio coupling capacitor work this may help. It isolates DC on each side but lets audio move from one side to the other. Audio Coupling Capacitor, how it Functions in a Circuit ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-PAPnwX6YiIM.html
Okay I think I get it now. And as per usual its a crappy explanation that's the cause of the confusion to begin with. Specifically this one from AllAmericanFiveRadio: "A 12 power supply, NPN collector is positive, emitter is negative. PNP collector is negative, emitter is positive." What the hell is that? You're just explaining the pin-out of the transistor. I might sound ungrateful but I've had it with retarded Electrical engineering explanations and terms. It makes it near impossible to learn anything within the field and so much is never explained. Like a decoupling capacitor! Do you know what gets decoupled? Train cars and trailers! Not an effin' capacitor and don't get me started on "bias" Do transistors have opinions now? The answer should have been: A PNP transistor needs a negative voltage supply. So you would need a power supply that provides a -12V rail for the PNP transistor and a +12V rail for the NPN transistor. This also explains why the positive rail in the schematic is going directly to ground at the PNP transistor. Relative to the -12V rail it is 0V and therefore effectively ground.
@@AllAmericanFiveRadio It is such a great circuit for a newbie like myself. Except when I try to go and hook power up to this, and a function generator. Things start to get weird. So I hook 12v up to the + and -, and then hook the + of the function generator into the cap. and the - to the ground the 12v is hooked to?
@@g00glian0 Look at the picture (link in SHOWMORE) Red wire is positive Black is negative NPN transistor on left PNP on Right Wire connecting capacitor from NPN collector to PNP base is red in video and black in picture
Hello, this was a very nice video thanks. Does anybody know where I can find more info on what are the specific resistors for (self-bias, fixed bias) and why are some large/smaller than others? Thanks
