These circuits usually won't work, except you are living next to a radio station and you are using a very long (4-5m) antenna. For the RF amplification you will need an RF transistor, which can handle those high frequencies. When you use a LM386 as an audio amp, make sure you use this 10µF capacitor between Pin 1 and 8 AND at least a 10µF cap directly at pin 6 and 4 and also an 10µF cap at pin 7. The LM386 can't handle this high amplification without a buffer and will otherwise produce loud squeaking noises. The other thing is: FM signals are not easy to demodulate. With discrete components this would be very hard...in these days you'll need a PLL FM-decoder IC or something like that. For testing purposes you can use something that is called (i don't know the english translation!) "edge discriminator". This is done, just by adjusting the variable capacitor next to the exact wanted frequency, as you are doing. But this sounds awful and if you turn the cap 1 tenth of a mm to far, you will hear nothing. You also need to keep the wire lengths as short as possible....you can't do it on a breadboard. The wires of your coil are too long. If you would solder it together directly, you would get much better results. Try to use silver wire, instead of copper wire for the coil! But even though: the results will be "experimental" and not satisfying...
Because all those click bait thots and or dumb channels with mediocre content hahaha “we are going to do a little bit of math “ I’m like wtf hahaha good stuff though I work on bikes so wiring is fun wanted to learn more about stuff like this so started watching this channel it’s great! Keep up the great vids
I hate slow videos. This is awesome speed. You can scan the content very fast thanks to it and then stop when neccessary when trying to do the same project by yourself.
Suggestion: To access those tiny trimmers, you can make your own trimmer driver from a small plastic paint brush handle. Just file the tip of the handle down to the shape and size that fits the trimmer cap, and now you have the correct driver with the added bonus of it not damaging trimmers like metal drivers can.
Just came across this channel I've watched several of your vids so far I'd have to say it some the better stuff I've seen on RU-vid. Keep it up mate you have some good stuff on here!
Thanks so much for this video ! I graduated with a degree in Physics and had to take a course in Analogue Circuits. Didn't do to well, but I'm hoping to start projects on my own.
Great video! I would recommend that you stay away from electrolytic capacitors for ac decoupling of your power rails. They're polarized and the noise can occur in both directions. I'm not really familiar with this particular circuit, I would probably shoot for a .1uF ceramic cap instead of that 470uF electrolytic one, though.
A common technique is to also put decoupling capacitors directly across the power inputs of your components like your op-amp. This can be more effective than just decoupling the power rails, because your breadboard itself could be responsible for some of the noise.
This is legit my favorite channel... I am always looking forward to new content being put up :D I'm an upcoming engineer/inventor and I love to build random stuff so naturally I'm going to love watching this stuff lol... A couple things I would really love to see in later videos are something solar powered (solar fire starter, solar taser, etc...) and I would really like to see some kind of give away cuz I would totally want a souvenir!!! Also I was curious where are you from/living?
thank you for helping me understand [rf], by seeing it and hearing what you said it finnaly sank in, sometimes it just takes the right teacher for me to understand something.
LM386 is not an OP Amp.. it's an actual linear audio amplifier and are commonly found in non stereo devices like a fax modem to drive the internal speaker or some toys that make sounds. Some PC speakers used them early on (one for left speaker and one for the right speaker) but now they use ond of the TDA IC varients for stereo sound amplification. Most of those cheap varible caps use plastic sheets to change the capacitance. same for modern dual gang tuning caps. The one you are using is a trimmer.and is VERY touchy, For the best band coverage you should use an actual tuning cap. That big .22uF cap is an AC line cap, it's overkill for this application but it will work lol
Great info but please insert a few commas and full stops, periods in your delivery as everything just rolls into a complete mush, many thanks for info.
Wow this is amazing especially on a breadboard. The audio amplifier part I’m good with. Could somebody please explain the principle behind the left part of the circuit? How is frequency converted into amplitude for the op amp to further amplify?
@J W I actually found out - this not a high quality FM circuit, but basically the way it works is that there is a principle called Injection Locking that says that a small signal will "lock" on to a Collpits oscillator and change its intrinsic frequency which is normally determined solely by the LC tank. So the antenna keeps changing slightly the intrinsic frequency of the LC tank. In turn the amplitude across the tank varies. The load resistor is voltage divided with the tank, so the voltage across it changes. Filtering the carrier is not necessary because the transistor amplitude stabilizes to audio frequency (you can see this last bit only through advanced math, it's not intuitive and usually doesn't happen; usually if you want an envelope you need something like a diode envelope detector). ( ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6774035 ) For it's simplicity this the HARDEST by far FM circuit to understand & the least intuitive. It's performance is also inferior to the usual ones.
@J W Thanks JW - same to you. The subject is pretty hard, but i'd recommend "Principles of Electronic Communication Systems" by Louis Frenzl. Unfortunately it's super expensive, but the 3rd edition (one before last) can be found used on Amazon for a reasonable price.
Must be honest. You didn’t write dots to separate wires connected, and the wires that don’t connect. makes the whole diagram false, hard to read, and complicated to create. Considering this is science we know how bad a small thing can make a circuit. ASIDE FROM THAT IT WAS A GREAT VIDEO THUMBS UP STILL.
Hey, cool video :D Just one thing: when filming the vlog type intros, you might want to wait a second before you stop the camera after saying a line xD
I'm still surprised that the receiver is still doing so well! because breadboard is not really suitable for radios and transmitters. yes it can work (proves it now!) but watch out for that next time... healthy and kind regards from the Netherlands! Rob
That’s cool! I’m in eighth grade and actually kind of understood some of this stuff. I am looking to become successful me sort of an engineer when I’m older. Are there any courses or kits that you recommend to learn something like this
Why does this circuit work? The LC part of the circuit is not modulating the signal, because the frequency of FM radio is changing. I believe it's only modulating the "centre" of the spectrum, so the sound is incomplete.
Plz use crystal instead lc tank for simple fix frequency fm and am receiver . Or using fix Freq 555 ossilator as transmitter ! I want to make pet Coller tracker .
I haveresently become interested about bluetooth connections I wish to make a big box speaker and makeing it connect through bluetooth but I am not aware of its limitations range, quality, speed of transfer and if I could even get it to connect. so got any ideas
If you do go to 6 Volts, you will have to put a variable resistor for the 22k one, I would go with 100k and start at high resistance adjusting down until you hear some noise or signal meaning you have regeneration. you could then measure the resistance you find best and put in a fixed resistor if you want to.
excelente amigo eres un genio yo he armado tu circuito del transmisor de radio fm y funciona perfectamente y tiene un muy buen alcance y a hora voy armar el de tu circuito de radio para ver que tal funciona los transistores 2n3904 no los consigo aquí donde vivo pero voy a probar con los c945 y el chip lm386 tampoco lo puedo conseguir pero voy a reemplazarlo por un tda2822 que es un chip estéreo pero lo coloco a funcionar en puente como dice la hoja de datos para que quede mono y suene mas fuerte con los 3.5 voltio saludos desde Venezuela amigo son muy buenos tus vídeos sigue así
@@guillermoviramontes851 sin funciono pero después de derramar varias lagrima porque el circuito es muy sensible a la capacidades parásitas y toca jugar un montan con la bobina hasta encontrar el punto donde funciona mejor
Could you make a video about something like... van der Graaf generator? Or other generator of static charge Or maybe on converting a shematic to a protoboard and how to convert it to a prefboard
Hi Transistor BF494 is not available in my country and your circuit with transistor 2N3904 I close it on the board, but it only makes noise, even I put the FM transmitter next to it near the circuit, it has no effect and instead only the IC gets very hot What is wrong? With transistor bf 199, the circuit has only distraction (noise) and does not take a station Thank you for answer me😞🌍
