What is an op amp? Operational Amplifier tutorial & super spy microphone circuit

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  • Опубліковано 14 гру 2009
  • Afroman goes over the basics of how to use an op amp (operational amplifier) to amplify tiny voltages, and builds a circuit to listen to very faint sounds with a microphone.
    LM324 Quad op amp: www.amazon.com/exec/obidos/ASI...
    Circuit diagram: www.afrotechmods.com/groovy/am... Check out my webpage www.afrotechmods.com for more videos about electronics!
    Twitter: / afrotechmods
    Facebook: / afrotechmods
  • Наука та технологія

КОМЕНТАРІ • 672

  • @Afrotechmods
    @Afrotechmods  6 років тому +11

    Interested in learning about wireless power? Check out this course I teach:
    www.udemy.com/wireless-power-to-the-people-wireless-charging-101/?couponCode=UA-cam

    • @daggawagga
      @daggawagga 4 роки тому

      Thank you!! I didn't even plan on learning this subject but it was just too interesting to pass up.
      Btw, do you plan on creating more Udemy courses?

  • @Bryan514
    @Bryan514 8 років тому +256

    No electronics tutorial is complete without cats.

    • @bonbonpony
      @bonbonpony 8 років тому +3

      +Bryan514 Now it's time for the cat to be a part of some circuit :D

    • @OmkarJadhav999
      @OmkarJadhav999 8 років тому

      yeah

    • @JavierPortillo1
      @JavierPortillo1 7 років тому +5

      Let's plug a cat to the mains! :D

    • @GoldenGrenadier
      @GoldenGrenadier 7 років тому +2

      I'd hate to see a cat on photonicinductions channel. "Till she pops" he'd say.

    • @EdgarsLS
      @EdgarsLS 5 років тому

      it's just common sense!

  • @FutureAIDev2015
    @FutureAIDev2015 8 років тому +123

    I like your use of cats!

  • @Culturedropout
    @Culturedropout 6 років тому +4

    Between you and Great Scott, I've learned more in a few days than I picked up from several semesters worth of college EE courses. Only about 40 years late.

  • @dr.g7898
    @dr.g7898 3 роки тому +3

    As usual, your video is the BEST. For all the naysayers about universities, I use your video in my classrooms, from AC/DC onwards. And build the circuits you talk about. Thanks Again. YOU ROCK!!!

  • @CREE8CHANGE
    @CREE8CHANGE 8 років тому +7

    Hey man- just wanted to say thank you for your videos. You really have a wonderful gift of easily explaining things. I watch some of your videos, on concepts I've struggled to grasp for a long time, and then it just clicks. Thanks for sharing your knowledge. Keep them coming!!

  • @amoghgajare2581
    @amoghgajare2581 8 років тому +59

    I loved the explanation you gave and that cat is so cute!

  • @Kj16V
    @Kj16V 11 років тому +1

    There are plenty of tutorials on opamp theory around, but this is the first one I've found that actually take a PRACTICAL approach - the only approach I can understand! Thank you and your technical afro!!

  • @citizenalex1934
    @citizenalex1934 7 років тому +5

    I will nominate this video as a BEST OP-AMP TUTORIAL VIDEO AWARD!!!

    • @Afrotechmods
      @Afrotechmods  7 років тому +5

      I will nominate this comment as the creme de la creme of comments!

  • @TrueMentorGuidingMoonlight
    @TrueMentorGuidingMoonlight 7 років тому +15

    Out of all the "Interesting Fact" videos I've watched for ECE207 prelabs, this is my favorite one.

  • @christaylor8142
    @christaylor8142 8 років тому +3

    Awesome explanation. Made complete sense the whole way through. The theoretical side with the schematic explained and then the demonstration at the end. Mint.
    Subscribed

  • @crossbones911
    @crossbones911 10 років тому +10

    Perfect. I was thinking about getting into electronics this summer and it looks like I'll be using your videos. Teach me your ways sensei

  • @Air3gg
    @Air3gg 8 років тому +2

    I'm so amazed how this video is 6 years old, yet the quality is so on point! Great job!

    • @alperenyurdakul1464
      @alperenyurdakul1464 4 роки тому

      I'm so amazed how this comment is 4 years old and how this video is 10 years old, yet the quality is so on point! Great job!

    • @TECHOLAX
      @TECHOLAX Рік тому

      @@alperenyurdakul1464 I'm so amazed how this comment is 2 years old and the heading comment 6 years old while the video is 12 years old, but it is still good and clear as the one made today

  • @ForViewingOnly
    @ForViewingOnly 13 років тому

    Simply the best tutorial/refresher videos on UA-cam. Thanks Afrotechmodman.

  • @m.a.2169
    @m.a.2169 9 років тому +5

    You're so awesome! Please keep doing these they're so fun to watch and straight to the point (:

  • @musicamex
    @musicamex 12 років тому +1

    your tutorials are brilliant, distilled and humorous. i intend to watch them all. electronics don't have to be snooze inducing or overly complex and you are switching on the most important switch of all. the "i can" switch. i explain this stuff to my music students and your tutorials will become part of the homework. you are a gifted teacher. kudos. keep up the flow bro---

  • @christianmarquez3143
    @christianmarquez3143 8 років тому +3

    That was really cool. I like how you demonstrated something that we can really use and really put together. Thank you!

  • @stevenchiverton48
    @stevenchiverton48 4 роки тому

    a circuit i built once before was a 4 mile mike and its super sensitivity and amazing gain makes it so sensitive it can hear the most tiniest whisper you can ever make 14 feet away and around the corner of a wall and thats amazing, the sound of my tiniest whisper is beyond faint, which means i have to have my mouth right in your ear so you can just hear it so with this circuit 14 feet away that would be considered impossible but it worked im recreating this circuit again , the circuit used 1m5 potentiometers which ive found dont exist online anywhere not even e bay so i had to make some changes hoping it would work but despite the feedback squealy it worked beyond what i expected . and i had to adjust it to reduce the feedback to the edge so its at the beginning

  • @martinest9458
    @martinest9458 5 років тому

    Literally the first tutorial where i get how the op amp works. Thank You !

  • @BrokenCapo
    @BrokenCapo 11 років тому

    dude, u have the best tutorial... quick and concise, easy to understand, and entertaining and funny to boot. love it

  • @EddieVanHalen1977
    @EddieVanHalen1977 11 років тому

    You have helped me learn a lot. Thank you. In fact, I think I have learned more from your electronics videos than from anyone else's videos by far.

  • @FantaBH
    @FantaBH 6 років тому +3

    I have seen your comment on Great Scot channel last night and that brought me to your channel, , still exploring it but so far , you are good and it worth sub. Nice job.

  • @KelvneMachado
    @KelvneMachado Рік тому

    This is the best video to introduce op amps I’ve ever watched

  • @masouddayaghi5923
    @masouddayaghi5923 2 роки тому

    I watched tons of videos about op amps and never got it, just now I got it, it was with a big distance the best viedo I have ever seen in this topic, thanks a lot.

  • @vincezzz9757
    @vincezzz9757 7 років тому +2

    Very clear and help me understand how op-amp works. Great video!

  • @guzziventure1750
    @guzziventure1750 8 років тому +7

    You're so good! Unbelievable great to listen and watch your video's. Impossible to express how great they are.

  • @otbway
    @otbway 9 років тому +57

    Engineering class at university would have been soooo fun if it was though like that...with actual real life application of an op amp, instead of hours and hours of solving complicate problems that you'll never see in real life....

    • @danns87
      @danns87 9 років тому +8

      otbway So true... might have ventured more deeply into HW instead of sticking to SW as I ended up doing. Now, years later, as I'm messing around with electronics in my free time I'm starting to recollect some things I learned, and all of a sudden they're no longer drab, boring symbols on a piece of paper - they're something tangible and useful.

    • @ioncasu1993
      @ioncasu1993 7 років тому

      just dont go to university and dont try to learn anything, cuz we all eventually die so its useless.

    • @oukid2633
      @oukid2633 7 років тому +1

      Feels existential crisis man

    • @ioncasu1993
      @ioncasu1993 7 років тому +4

      " instead of hours and hours of solving complicate problems that you'll never see in real life..." hahahahaha roflt omfg you're such a noob hahahahahha im literally rofling....

    • @___xyz___
      @___xyz___ 5 років тому +2

      Guys, look! Maxwell is trying too hard to become a meme again.

  • @VallabhaHampiholi
    @VallabhaHampiholi 9 років тому

    Seriously who have disliked this video? That was an excellent video depicting all the important stuff about Op-Amps.

  • @kamaleldinmohamed1702
    @kamaleldinmohamed1702 6 років тому

    dude, you cant imagine how much thankful I am

  • @christophercanal4
    @christophercanal4 11 років тому

    Fantastic Video! I'm an Electrical Engineering Student, and you just cleared up so many questions for me. Thank you.

  • @James1toknow
    @James1toknow 10 років тому

    Real good stuff. I'm currently in EET and just about done. very cool lab.

  • @4dirt2racer0
    @4dirt2racer0 3 роки тому

    jesus man once again youve taught me something extremely important that iv been trying to confidently n comfortably understand for years which is negative voltage, iv had a pretty good understanding of it but iv never really had a good "feel" for it.. idk how else to explain it thanks so much i wish i found this video 10 years ago lol

  • @agentgates
    @agentgates 14 років тому +1

    Hi, thanks for sharing this video. This is what I was looking for! I've got tired in the harsh theoretical lectures without basics. Finally something that I can use after first watch. :)

  • @LT89NL
    @LT89NL 11 років тому

    Just the cat alone already makes this vid awesome, not to mention the actual information, which is already really well explained and clear. Thanks for uploading it!

  • @danielsalloum3006
    @danielsalloum3006 7 років тому +1

    You make me feel geniousish with every video. So addicting.

  • @doodh_jalebi
    @doodh_jalebi 12 років тому

    it has been 5 months and i couldn't understand these things! YOU ROCK!!!

  • @erichoogstoel9417
    @erichoogstoel9417 8 років тому +42

    cat noises amplified > ASMR

    • @Afrotechmods
      @Afrotechmods  8 років тому +17

      cat noises > EVERYTHING

    • @HKCREATESUNIQUE
      @HKCREATESUNIQUE 4 роки тому

      Afrotech mods. Why you are not making videos now

  • @MultiSchuman
    @MultiSchuman 7 років тому

    great video my friend. most informative. i was amazed you posted this in 2009. you are doing world a great service. thanks you again. keep up the good work.

  • @LNTutorialsNL
    @LNTutorialsNL 11 років тому

    I'm Dutch and 14 yo, and the subs help me a lot with understanding everything you say. Thank you!

  • @randywatson8347
    @randywatson8347 7 років тому

    Nice video. I hope to know more about how single supply opamps work when it's single battery operated

  • @johnbattaglia6369
    @johnbattaglia6369 6 років тому

    Great balance of info and humor. Love the cat at the very end!

  • @petegabler9528
    @petegabler9528 9 років тому +5

    Seriously your tuts are gr8
    and so is your Sulu impersonation : )

  • @snappex
    @snappex 14 років тому

    I just made this and most of what I was getting was the local radio-station... :)
    Thanks for a great tutorial and keep making awesome videos!

  • @MrChannnnnnnnnnnnnnn
    @MrChannnnnnnnnnnnnnn 8 років тому

    In less than one minute, I was able to understand the use of opamps! thanks!

  • @marciokoko1
    @marciokoko1 8 років тому +1

    Gr8 explanations. Do you have videos for explaining voltage regulators, lm317 and lm7805?

  • @happyduck70
    @happyduck70 8 років тому +2

    You've got great tutorials! Keep it up!

  • @Afrotechmods
    @Afrotechmods  12 років тому +1

    @davidenelson Contrary to what is presented in this video, the better volume control circuit would be to have a fixed gain amp (e.g. gain of 10 to 20) and then use a potentiometer to divide down the input voltage.

  • @Juan.Jose.Jaramillo
    @Juan.Jose.Jaramillo 7 років тому +3

    its nice how easy you put words so we can understand.

  • @Car_toz
    @Car_toz 8 років тому +1

    Great videos, well cut and to the point ...

  • @bcsupport
    @bcsupport 13 років тому

    @Afrotechmods Awesome. Thanks for your help, and your tutorials rock !

  • @muzammilahmed2517
    @muzammilahmed2517 7 років тому +2

    very precise and to the point ....excellent video

  • @learnerlearns
    @learnerlearns 7 років тому +1

    Toaster oven ding = brain done. Best laugh I've had today! Thank you!

  • @neatpolygons8500
    @neatpolygons8500 8 років тому +1

    Dude! you are awesome! college makes me hate electronics you make me love it again

  • @Xempt_One
    @Xempt_One 12 років тому

    good circuit, the ones we built in electronics were twin output amplifiers, very simple to make, a few caps a couple resistors and the IC

  • @e33ie1970
    @e33ie1970 9 років тому +2

    Great video and a fun way of teaching. Thanks

  • @darcam
    @darcam 8 років тому +1

    Thanks for the lesson, I sure still have a lot to learn. Just hope i don't lose my mind trying to.

  • @johnszott956
    @johnszott956 4 роки тому

    Great video, you gave an easy way of understanding op amps . Thank you

  • @longchaojia1040
    @longchaojia1040 8 років тому

    WOW This explanation of amplifier is amazing. Easy to understand and funny all the way.

  • @OmarELKADMIRI
    @OmarELKADMIRI 11 років тому

    He is a big help for any electronic level.

  • @Jajaho2
    @Jajaho2 7 років тому

    Thank you for taking the effort ofmaking this.

  • @richards8827
    @richards8827 7 років тому +1

    Nice diagram showing how to create a duel power supply.

  • @VincesEngines
    @VincesEngines 6 років тому +1

    Thanks for this ,you have a great way of explaining.

  • @tobortine
    @tobortine 11 років тому

    Love it. Clear, straight forward explanation.

  • @isfiyiywafibc6qaiiiiiiiiii570
    @isfiyiywafibc6qaiiiiiiiiii570 8 років тому +1

    The theory behind op amps is actually really interesting.

  • @maseay91
    @maseay91 9 років тому +2

    awesome. I've always wondered.. how is audio collected by a microphone and turned into a voltage ?

  • @Afrotechmods
    @Afrotechmods  13 років тому +1

    @alpha001ful Lower resistances means more current needs to be drawn and that's easily avoidable. And a small signal op amp can't deliver enough current to power things like a fan.

  • @georgezanfir
    @georgezanfir 8 років тому +1

    i just wanna say THANKS dude !!!! you save my project with this vedeo :D

  • @simbaliya
    @simbaliya 7 років тому +1

    A question here, in the schematic @ 03:15, I think between R1 and ground there should be a capacitor to block GND level from negative feedback network.

  • @voidmansions
    @voidmansions 13 років тому

    A perfect video. Informative, to the point, and also very droll. Full marks.

  • @PietroGazda
    @PietroGazda 11 років тому

    Thanks, I'll think about it. I still have it on solderless breadboard trying to add more features (switch to gain change, power switch and LED etc) before putting it in box

  • @bgabor9505
    @bgabor9505 11 років тому

    This video is very usefull!! Thank you very much it helped me a lot becouse i just started learning about OpAmps. It made it very clear and simple!

  • @JonathanAnon
    @JonathanAnon 12 років тому

    This is brilliant. Clear and concise.. .... And the brain bit made me laugh... well done

  • @tigoxbrata
    @tigoxbrata 12 років тому

    you rock man you're simply the best you helped me so much at school!!

  • @alessandropagliara3453
    @alessandropagliara3453 8 років тому +1

    Thanks...really easy explanation and complete!

  • @MohammadTawaha
    @MohammadTawaha 9 років тому +2

    Really smooth,funny,Niiiiiiiiice and the most Important it's really Helpful tutorial>>> Thanks
    god bless you
    "جزاك الله كل خير"

  • @galax574
    @galax574 10 років тому

    Thank you for your video. I have recently modified the circuit,using a LED instead of an ear-plug. But I come across a problem: How can I increase the sensitivity of the circuit, so that even at a quiet background, noise can also be picked up at the output LED?

  • @rlrsk8r1
    @rlrsk8r1 9 років тому +7

    So I just built this circuit with a gain of 11, using a voltage divider to give me +9, -9 and 0 volts from an 18V supply, and I hooked it up to my Raspberry Pi's audio jack. Then I played this video on the Pi, piping the instructions on how to build this amp, through this amp.
    Recursion is fun.

  • @doctorazizli
    @doctorazizli 6 років тому +1

    Hi. İt is a good idea to use 2 batteries to create positive and negative voltages. I wonder whether it is possible to the same with 2 Lab power supplies?

  • @039dalekmoore2007
    @039dalekmoore2007 10 років тому +10

    working op amp equals happy cat ; )

  • @Shub428
    @Shub428 9 років тому +1

    Oh man thia video was just amazing...!! 😊😊
    Thank you for it... 😊
    Keep growing...!!

  • @Afrotechmods
    @Afrotechmods  13 років тому

    @hyperboogie Normally the resistor is needed to set the cutoff frequency but in this case it's also essential because it acts as a pulldown to ground, so the signal ends up swinging from -10mV to +10mV. If all you have is a capacitor sometimes the output floats around DC biases you aren't expecting.

  • @vitalcomputing6298
    @vitalcomputing6298 9 років тому +1

    Hey Afroman, Just wondering where you came up with the value of 5k for "powering the microphone.. Is this because the mic is 5k impedance as well so that the bias will be set at 9V/2 ?

  • @jstro-hobbytech
    @jstro-hobbytech 2 роки тому

    Your videos are great brother. I find it funny how you started out with an old owon and now you've got that nice free keysight they give all the channels that get a good following. Not an insult. You deserve it and it really ups your video quality.

  • @ronaldlogan3525
    @ronaldlogan3525 3 роки тому

    I always have thought that the LM324 was a single positive supply. The data sheet from Texas Instruments says pin 11 is GND pin. I know the LM741 is a 2 rail op amp, but I never new the LM324 is also.

  • @cassvirgillo3395
    @cassvirgillo3395 10 років тому

    Hi Afroman, thankyou for the entertaining and always informative videos. ATM, Dazaro3, AndyDaviesbythesea, and AllAmericanFiveRadio are how I'm learning electronics and I'm learning, thanks. Keep making tutorials, thier great. C.

  • @blaisenuthak
    @blaisenuthak 6 років тому

    That was explained extremely well... thank you!

  • @boy_deploy
    @boy_deploy 7 років тому

    Featuring AfrotechCat... 😄😄😄 Nice video man 👍 love your tutorials

  • @haloded
    @haloded 10 років тому

    awesome!, simple yet effective way to explain. I hate those long videos.

  • @blackseastudiohk
    @blackseastudiohk 9 років тому

    short and clean, like this tutorial

  • @ElBellacko1
    @ElBellacko1 6 років тому

    Beautiful tutorial

  • @nickb1875
    @nickb1875 5 років тому

    I guess this circuit plus FM transmitter will make a great wireless mic. Can u pliz make a video on that

  • @Afrotechmods
    @Afrotechmods  13 років тому +1

    @bcsupport Totally! But not the op amp I used. You would want a high speed buffering amplifier. Analog Devices, Linear Technology, National Semiconductor and Texas Instruments are good places to start looking.

  • @PietroGazda
    @PietroGazda 11 років тому

    Thank you! I've finally made my guitar pre amplifier thanks to your video. But the potentiometer at the end... I think it woud be better to connect it like voltage divider, so one end of potentiometer goes to op-amp output, second end to 0V and the middle to speaker or in my case jack output.

  • @EranMurat
    @EranMurat 6 років тому

    +Afrotechmods Can you please explain why a high pass filter is needed after the microphone? You said it is needed to make sure only AC voltage reaches the op-amp, but that can be done with a capacitor alone. Is there a reason to also block low frequencies?

  • @mrchiccolatte
    @mrchiccolatte 11 років тому

    Hi Afrotechmods, when can you have a new video tutorial? I've been waiting it. You're a big help to electronic beginners.

  • @RajSekharK
    @RajSekharK 10 років тому +3

    Amazing.... finnaly got a place where i can kill my hunger... thanks a lot... loved your tutorial....

  • @allahsever2705
    @allahsever2705 7 років тому +1

    man i want to like this video 5 times. thanks alot

  • @TheOddOne2
    @TheOddOne2 14 років тому

    Superb as usual!

  • @NoFear4XJs
    @NoFear4XJs 10 років тому +3

    You should put together a DIY package for the 2, 9 volt battery version.
    Would make it more inviting for people that are curious enough to think about it but get lost or discouraged when looking for the parts.
    If you do include a mic jack and a speaker wire output clamp.
    Would also be great to see one for an mp3 stereo amp with stereo speaker wire clamps, for this if I was you I would go for quality sound over a price savings of a $20 dollars..
    Thanks again for another great video,
    Cheers

  • @OmkarJadhav999
    @OmkarJadhav999 8 років тому

    Finely explained, grateful !..and the cat adds up to the presentation, adorable.. ; )