TSP #15 - Tutorial on the Theory, Design and Characterization of a Single Transistor BJT Amplifier
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- Опубліковано 8 лип 2024
- In this episode Shahriar presents a tutorial on the design and characterization of a single-stage low-noise bipolar amplifier suitable for audio applications. Given a set of specifications, a common-emitter topology is investigated. The circuit employs a beta-insensitive biasing scheme which is simultaneously optimized for maximum output swing. The small-signal gain of the circuit is calculated and the bandwidth is set for audio frequencies. A non-inverting operational amplifier is used as a second stage to achieve the desired overall gain. The circuit is assembled on a breadboard where the gain and bandwidth are measured and compared with design specifications. As the final experiment, the circuit is used to amplify signals from a microphone.
The Signal Path
www.TheSignalPath.com - Наука та технологія
My expertise is in mm-wave integrated circuits for wireless and wireline applications. You can lookup my work and publications through Google Scholar. I have also been playing with electronics for 20 years, since I was 10 years old.
The Signal Path I like that you began playing with electronics at 10 years old. I did the same. I've been an engineer for 45 years. I'm 66 years old and still learning. The more I know, the more I realize that I don't know.
Dear Professor Shahriar,
I want to build a system where I can monitor all radio frequencies at once, within the 10-20 mile radius?
Is there a way a hobbyist can do that with say dozens of SDR USB Dongles and a few Raspberry PI3s? Self-financing has that "being poor" side-effect.
I have already made the most sensitive 3D Geiger counter possible with SI-22G tubes.
Also a Light spectrometer using plans from the internet (public Labs). They work great.
I am currently working on computerizing my 6" Newtonian telescope, and attaching one color and one IR RPI cameras, green 500mW laser pointer, Spectrometer,... to be attached to the body of the telescope. So, when I aim at an object with the laser, I would see it in both cameras, the telescope, and the spectrometer.
The Chilean and US Navy videos on those UFOs, has proven to me they exist and gathering scientific data, is the only way to go towards figuring out what these things are, and how they work.
Can you provide some guidance as to the easiest/cheapest way for a technologist to detect and record local EM anomalies to be studied later?
Merci. Khoda Hafez.
@@ufohunter3688 By all radio frequencies at once, what are the frequency range you are talking about?
Could you make a tutorial explaining the basic elements of a RF digital transceiver such as a Bluetooth or WiFi modem?
@@billmoran3812 Its nice to hear that someone so experienced keeps learning. I only really started messing around with electronics about 2.5 years into my degree (I would have been about 24 around that time) and was sort of angry at being so lost - I thought I should be able to understand it all since I'd been studying it all in uni. Lately though, I'm starting to appreciate that this stuff can be really hard, and that there is no substitute for spending a lot of time, reading, watching, doing, making mistakes and learning. Hope to be a lot better at this stuff one day! Electronics is awesome.
I'm an Electronics Engineering student and I found this VERY helpful.
This is a very nice lab exercise that I wish I had back when I was working my BSEE. I bet some of my professors hadn't designed one amplifier and were teaching amplifiers theory!
This is one of the clearest explanations of theory that I have ever seen in decades of working as an Electrical Engineering Tech. Good Job! Keep up the good work.
Thank you for sharing your insights and understanding as you have in this video. I've been looking for a simple one transistor amplifier circuit that actually works when I build it and here with you I have gotten so much more. I'll probably post something after I build it.
Thank you, I will correct the problem. Yes, the 10nF is calculated for low-pass operation. If you want to only use transistors, you can design another common-emitter stage to follow this one. Just make sure you don't use an emitter capacitor again the whole thing would become very non-linear.
At 7:09, you consider Signal Swing.
I think the same clip is repeated at 9:33 to 11:56, which you could delete.
Very good lesson. Enjoying trying to keep up!
Cheers.
Matt
Agreed. The clip repeats twice!
As I'm not an engineering student, most of this was over my head. However, I believe I can use your excellent video to construct a simple audio amp. Thanks, you're a great teacher.
That has got to be the neatest breadboard I've ever seen, and a brilliant tutorial.
You're extremely talented at making these concepts easy to understand. Great video!
Very nice explanation. The information you give makes the topic less abstract and more concrete.
Thanks a lot for this :)
Cleared all doubts and helped me to organize all the equations and tools I had learned theoretically to practically build an amplifier.
You are magnificent. You are unique on youtube on how good and indepth your videos are. Bless you!
Thank you for this, I love your design videos, especially those that go "back to basics". Cheers!
I've been trying to get my head round this subject for ages. All of the explanations I've seen have so much essential information missing. This video is the final piece of the puzzle I needed to understand it. Thankyou :)
So far, this is the only one I've seen that properly explains signal swing and what VCEsat is. I had to look up what gm and Vt were though - never heard of those before.
THIS VIDEO IS GOLD! Only wish I found this last year.....
Excellent video! Im not an engineer but i understand some of the theory. As always, u have a great method of teaching and explaining electronic things. I hope to see more new videos as your content is possibly one of the best out there. Thank you Sir.
learned more in this one video than all the other stuff I have read on this subject combined. Great job!
This is one of the best tutorials. very clear.
Excellent job Shahirar, Great English and very good explanation in details with good speed!
Just jumping into all of the design stuff and I really love it. Fine job on the video and the content. As Joshua mentioned as well, that breadboard layout was very clean. I'll be back for more.
Thank you so much for the great tutorial. I don't think you'll ever know how valuable it's been. Keep up the great work!
I finally understand why Re, Ce, and Cc are needed (most just hand wave this part) Thanks for the clear explanation.
You are welcome.
I really enjoyed your thought process and approach. Thank you for all your efforts to teach us.
You should make more videos like this one. I love theory/design videos. Thank you, and keep it up!
All I got is love for you thank you for teaching me how to build a circuit and all the potential that came with good cookie stuffed
Wish we had more tutorials like these from you.
The dual +/- supply is common for analog circuits. It also makes using the opamp easier as a second stage amplifier. A single +5V supply can also be used. The same principles apply.
I built the circuit and it works! I'm still working on the input because my function generator's minimum output voltage is too high (reducing the amplitude of the function generator to milivolt range is a project right there). Today I'll try a microphone. If you want to build on this basic circuit adding a second transistor or what ever it would be much appreciated.
Anyway, Shahriar thank you again for this very helpful video.
Thank you for uploading this very helpful video. I finally found a video which uses the same notations and abbreviations as the university I study at does. Greetings!
Excellent video. Some of the math/theory was over my head but I followed along okay. Thanks again!
I teach this material at the beginning of an Analog Electronic course in fourth year of an EE bachelor degree or first year masters degree depending on the university.
That seems like quite a late time to teach this?
@@zetaconvex1987 we study it in the second year but our bachelor degree is only 3 years
thank you very much. it would be great to push white noise through this so we can watch the frequency response. its fascinating looking at the low passing because it wasn't a very wide Q. i'd really like to see a video analyzing the noise of this circuit. that'd be amazing. thank you for making this. you're the man
Great job man! The signal is beautiful.
Very clear and informative! Thanks!
Excellent instructional video. Thanks
Beautiful. Love your show!
Outstanding video as usual. Thanks for sharing.
Good work. Design is wonderfully explained!
Once again, perfect tutorials, thanks, thanks.
Thank you for this.Please do more of this stuff (analog audio & Synthesizer) .
Thanks!
A very good explain and demo... thank's alot for your work...
Loved it mate... :) Keep up the good work of helping us.
Great work .nice equipment
this is very helpful. thank you so much!
I hope you make more of such videos. Going into design and development of electronic circuits
This is awesome! Amazing explanation!
Excellent Video! Thanks a lot.
seriously i have read 3 college books and watched a lot of lectures and they all fail to ex-plane properly what role that capacitor is having in that circuit. good job man god bless you
thanks for all your effort
Brillant work Man. Thanks.
I've really enjoyed in this Video, thank U for this Explanation
nice video, this was one of the things i was missing to learn
My calculations of the signal swing is correct. Perhaps what you are trying to say is that the signal swing can be improved. That is true. However at the cost of causing more beta-sensitive biasing. Dividing the signal equally between the three elements is a compromise between beta-insensitive biasing and swing. Furthermore, it is true that there is no emitter degeneration. However for an application where the input is less than VT (25mVpp), the distortion is not of significant importance.
Due to availability, I would have to make the 1st stage amplifier with following component values: BC 547, Rc=Re=1k, RB1=14k, RB2=10k, Cc=0.1uF, Cb=Ce=100uF
Will the amplification calculation (i.e. A=-64) and the practical results (i.e. Vin=5Vpp, Zin=50, f=2.5kHz, Vout=300mVpp) hold (under experimental error allowations)?
Transistor calcs are confusing! Great tutorial. Want more like this!
That RC=RE is a compromise to achieve beta-insensitive biasing (I called it Iq accuracy, but beta-insensitivity is a more precise description) while maintaining signal swing is understandable, though I felt it wasn't made clear in the video; in the context of the VRC=VRE discussion (12:00), it would seem as if RC=RE is optimal for maximizing signal swing. The importance of the distortion is largely a matter of taste, and of course, what the amplifier will be used for.
Love your vids, keep it up.
I also find that explanation a little lacking, more after having been watching other videos searching for a more in-depth answer on why are Rc and Re chosen as they are, and finding conflicting answers. Absolutely think this video is gold, no intention to devalue it a bit. Thanks Shahriar!!
Great video!
Just a little correction. Human ear can perceive sounds down to 20 Hz, but for a microphone amplifier 50 Hz may be a rather good threshold to pick up less hum and different mechanical noises, wind for example. Humans can actually perceive frequencies less than 20 Hz not as sound, but as vibration. It could matter for say a good studio mike. If somebody would record say a sound of arriving train, it would be rather dissapointing to not have this vibration low-end in the record. This details don't really matter for the purposes of this video of course, but I thought it may be interesting.
Some people can hear below 20Hz and spectral content above 20kHz also plays a role in signal shape at far lower frequencies, we always designed for 5Hz-100kHz, but with EQ on the passband gain. RIAA is a good starting point, most people prefer a smiley face curve : ) so shelving filters are good for the general public. You’re correct, design for flat response across the range will sound terrible to most people even though it’s technically perfect...
Very nice tutorial. Thanks.
Great Video!!!!
By putting Re the biasing becomes independent of Beta, and so does the DC gain, which in this case it is equal to unity as there is a lot of negative feedback. On putting the capacitor Ce the AC gain is still dependent on Beta. I like the manner in which you found this maximum gain. THis AC gain I presume may be controlled by adding another resistor above Re, unbiased by Ce.
Bravo!
Omg ur the best I have to watch it again
Vt is the thermal voltage and is equal to KT/q. This is a physical constant.
Thank you!
Very useful. Thank you.
Great video :)
Thanks.
Nice video, thanks! Just I didn't understand what is Vt and where it comes from.. Could you explain that?
You mentioned noise compensation biasing optimization, could you clarify or make a video on that at some point?
That and/or differential amplifiers
Hi
This is probably the best explained transistor tutorial on UA-cam . may I ask you why you chose to have a negative voltage. I am new to transistors and would appreciate your explanation.
Thx
Well done tutorial. One question though. How did you choose the bias voltage? (RB1 and RB2)
Is it possible to make a tutorial on rf amplifiers? I can't find one anywhere!
hey man that's nice, i'm going to put some plants in my class lab :)
Thanks a lot
Thank you for your time and your skills. i'm aware that these videos take allot of time to make.But if you can, can you do a video on explaining a bjt transistor datasheet. Thank you.
What values did you chose for the 20kHz BW and the CB?
So glad you said that, i thought i was the only one.
nice totorial
Have you done or plan to do a video on setting this amp's PS to be a single (5V, gnd) instead of split supply?
What needs change if I want to use a 9 or 12V supply?
Thanks. You are a great teacher and thanks for the notes too.
This was a terrific video! The only thing that could have made it better is if you used a hybrid equivalent diagram to explain the Q-point voltages. I also have to say I am green with envy at your lab; you have lots of nice toys.
Thanks for the good clear explanation. I noted that you're using a BJT for the first stage to avoid noise, but then you use an opamp for the second stage. Would the noise come from the large-value feedback resistor required to get a gain of 100 out of an opamp? Is that also why you used a non-inverting opamp configuration, to use a smaller-value feedback resistor? Thanks.
Hi
in your final schematic are Rb1,Rc and Cc connected to +2.5 volts and Rb2 ,Re and Ce connected to -2.5 Volts ??
Thx in advance
Thanks
how do we know what RB and RE are to calculate the first equation?
the young Shahriar :)
I'd love a tutorial on circuit techniques to lower the noise of an amplifier
Good Video and thank you. In the video, you repeated the signal swing section at 7:15 and 9:32 otherwise is perfect. About the design, Did you calculate the 10nF capacitor like a low-pass filter with the collector resistor? and if I just want to use transistors (without a op-amp), Do I have to use a common collector stage before a common emitter stage?
The noise was actually from the oscilloscope. There was a problem with the beta firmware I was using. The noise is not from the circuit. :)
hello sir am not very familier with the analog circuit design so i find difficulty in relating the base circuit to the emitter collector network.my doubt is how did you get the values of base resistors i.i r1 and r2?
best of explain Iranian boy, Thanks, if possible make video about NOISE in high frequency range...
My question is that the first bipolar stage of the amp is phase shifting the input singnal, and the second stage is configured to be non-inverted, so the output signal is inverted according to the input signal. This can be solved if we configure the second stage for inverting the signal? Sorry if this was mentioned before. Thank you for the great educational videos!
Hi, very interesting, i am surprised how the mathematical theory can be close to the later practice and measurements on electronic
I have a question to modify this project.
I would like to receive only positive, top part of the amplitudes, but the amplitudes don't come down to zero, only stop for example on +0.5V before zero, and again rising up ....
It could be done with 4 diodes to take also use of the lower amplitude ....
Thanks for any suggestions
thanks
Nice video, but some important information is missing. How did you derive 14 Kohm for RB1 and 10 Kohm for RB2?
You set Ic = 2mA, how did you come up with that value? please ^^
what do i have to learn before i can understand this. im trying to learn electronics. i am studying a level 3 course, and intermediate radio course. i dont know any of this.
what degree covers this stuff please
First I'd like to thank you for all the amazing content you've been shared with us! My question is why the input and shunt capacitors are polarized type (eletrolytic)? They shouldn't be unpolarized ones because the alternating voltage? Best regards from Brazil!
It's because of the values. High capacitance values are just available for electrolyte cap types or for tantalo types. The electrolyte ones are less expensive and easily available. Hello from Brazil!!
Can you make a sequel video showing the a/d converter and power opamp is added so it drives speaker? That would be more complete and motivating. By the way, what opamp did you use in this video? Does it use two power source or one?
12:25 why do we want to maximise the voltage across Re? I understand that Re should be high for beta independent biasing thus also V(Re), but should it be as big and same as voltage across Rc?
Many thanks for the video.
can you give an preamp circuit design with the parameters and procedures??
At about minute 7 you set up your equation. In it you said Ie =Vb + 2.5 , etc. But you pointed at the -2.5v at the bottom. Which is right, 2.5 or - 2.5 ?