Love this and congrats ; great job . This year I ' ve managed to obtain similar performance with a different configuration of a twin transistor model and two AA in cascade , thanks for your nice contributions .
This is a regenerative receiver that detects FM by using the slope detection technique in which amplitude varies with frequency. It uses a Franklin oscillator, which is the most simple and easiest oscillator to implement. As a matter of fact, sometimes you can remove either transistor and the circuit still can oscillate! What we need here (to improve) is a way to reduce the oscillation amplitude to improve signal readability (reduce noise); this can be done best by making the 22 k-ohm resistor variable. I would experiment with adding a potentiometer at the input to reduce the amount of signal that comes from the antenna. While this sounds counter-intuitive, it’s the most effective way to improve selectivity of the radio (thus, reducing noise). Reason being: regenerative receivers can amplify with extremely high gain (inferior to only the super-regenerative receivers, also an invention of Armstrong). With too strong of an input, a signal doesn’t make too many loops around the regenerative circuit before output becomes too strong. Consequently its Q is not high and its selectivity suffer (too much noise comes from nearby frequency). Reducing (all) incoming RF signal allows more room (so to speak) to amplify before the total energy reach the ear, this enables higher Q, higher selectivity meaning the ratio of signal of interest over surrounding noise is higher.
All good information. Thanks for taking the time to share the information. I do agree that this is slop detection and you can even remove one of the transistors. At some point I want to try re-doing this video as I did it a number of years ago. Thanks for writing - de N1KRB
Thank you very much for your fast reply sir though it will be not work good but then also if I can hear a little bit then also I will be happy I'm studying in 12 standard but many my teachers told me that it can not work with this simple circuit so I will definitely prove them wrong . I have a great interest in making such projects and good going sir keep more educational projects I will always remember you if it work thank you sir
Thank you very much sir finally I can hear 2 channels. Thank you very much sir .After I tried number of variation I finally got success and thank you again sir upload more educational videos.
mohit panjabi video is very perfect but you need to add 5 pico Faraday capacitor before antenna and it would work perfecly if you have fixed circuit properly
Good to hear you were able to make the radio. It is a fun-simple circuit. To make a digital control tuner you would need a digital-to-analog IC. A digital keypad puts in a digital number at the input of the chip and an analog voltage is produced at the output to control a varactor, which is a voltage controlled variable capacitor.As the analog voltage is raised or lowered, this produces a change in the capacitanceof the varactor. The varactor operate in parallel with a coil which forms the tuned circuit.There are plenty examples on the internet how this is done. The trick is to find one that works in this situation - and the other trick to find the parts at a decent price. I will do some research and if I find something I will share it with all.
Hello Sir. I was very surprised because it worked perfectly! At first I used the lm386 as an amplifier but it made noise so I decided to use one of those amplifiers from china, *_PAM_* or something, and it worked perfectly !!
You are so right, PAM8403 is a great class D amp and it comes cheap on a module ruclips.net/video/oB-k0tA1G2M/видео.html duckduckgo.com/?q=PAM8403+Audio+Amplifier+Module&t=ffcm&iax=images&ia=images www.diodes.com/assets/Datasheets/PAM8403.pdf
On the subject of small FM radio receivers, I had a radio from a cap. I think it was solar powered or used button cells. It had 6 transistors and one integrated circuit, among the components. It had an earphone. The circuit itself was very compact. Another FM radio I had was from a promotional giveaway, if I recall. It had 2 transistors and one integrated circuit. Again, the circuit board was very small. It used three triple A, 1.5 volt batteries. It used earbud type headphones. Your circuit looks pretty neat. It's a similar concept to the second FM radio I mentioned. If you lived a hundred miles or kilometers from a major city, I wonder how sensitive these receivers would be. I know that attaching a wire from your FM antenna to your cable outlet for your T.V works a charm to get distant FM radio stations.
yeah sir you may be right I have an Fm pocket radio in which sometimes when I touch the antenna it get works properly so on touching the capacitor I may get the different frequency and now I will surely try this one but when today I was going to buy transistor to my local shop he also told me that we can not make a radio from this much simple circuit he also told me that I will just waste my money as this useless circuit won't work but then also I bought those transistor and said to him though I will waste my money but I have an trust on this channel and I think that it's not fake and I will do my best. Thank you
Thank you very much for this circuit. I assembled it and it worked quite well at short range. Do you have any tips on increasing the sensitivity so it works better at longer range?
The only thing I can suggest is to play with the antenna length. As you can see, it is a very basic circuit design with very few options for improvement. Good Luck
Hey, did anyone make it work with 2N2222 or 2N3904? It's inpossible to get BF transistors where I live.. I've been trying this layout out with the the wrong (4-10pf) variable cap and have had no luck of making it work. Gonna try it all out today with the 20pf varicap again. Any extra tips for assembly n such? Thanks!
Thanks for your question. My radio worked differently in different locations. Down in my basement, I clipped on a wire of 1 foot it that worked for me. However, up in the kitchen ( where I shot the video) I used a transistor radio telescopic antenna which was mounted vertically in a wood block. This is something one has to experiment with.
Hi, I would like to build this circuit for my school project. I saw your other video about the antenna booster and I would like to use that circuit on this one. Can I connect that circuit to this one on a single battery?
+CyberBoy8799 Yes and no. I've not tried it before, but in theory, it should work. However, the value of the choke needs to change on the antenna booster to accommodate the frequency of the FM band. Follow this link for more info on the booster:www.seekic.com/circuit_diagram/Amplifier_Circuit/Active_Antenna_for_AM_FM_SW.htmlTips on making the radio: 1) play with the length of the antenna - every situation requires a different size - 2) keep the coil and the tuning capacitor close to each other (they feed off of each other) - 3) best to use a tuning capacitor with a knob because stray capacitance from fingers, coming close the tuner, will effect the performance and 4) don't forget the 10ufd cap between pin 1 and 8 on the LM386 needed to boost the output.Good luck
It obviously detects FM but if that was the best signal quality you could get, it still needs work. Good job on the video. Maybe you could show us how to improve the design. Do you think the poor sound quality is due to the speaker or the minimalist nature of the circuit? I know the lm-386 produces fairly nice sound quality, so it's probably not that.
Howdy. Yes. That circuit works quite nicely. It is a slope regenerative circuit . One might use a 47k pot. to adjust regeneration for best sound quality instead of the fixed 22k resistor. Another addition would be to use a low pass RC filter before the op. amp. to correct the FM high audio bands boosting. The RC time constant is 75 us in USA and 50 us in Europe. The two transistors form an oscillator that uses the incoming signal to uphold oscillation. Detection appears as current changes.of the oscillator as it fights the FM deviation. Regards.
Thanks for taking the time to reply - all good suggestions. I think you're right. As the FM slope changes, the voltage change it produces at the input of the .22 ufd cap, produces the audio signal of of the FM station being tuned in. The next time I play with this circuit, I'll put in a pot in place of the 22k resistor. Again, thanks for your suggestions and remarks.
@@rbashta Howdy again. I forgot one thing. One might connect a 4k7 resistor in series with the pot. to avoid accidently turning the pot too low which would destroy the oscillator transistors. May I advertise my blog: "1. Table of blogs. Blogiluettelo." which is a list of blogs. I have tried several circuits of FM detectors. The blog circuits have all proven to work Regards.
Do you know what a reason would be for deep buzzing noise coming from speaker? its almost as if the coupling capacitor does not do its job and the output of the op amp is constant dc current??
Use a 9v battery with a 5v voltage regulator(7805) or LM317 set it to work at 4.5 volts Or use 3 x AA or AAA ...etc. Sometimes something from AC or Power Supply causes problems. And run it outside away from different electrical/electronic devices.
I made an am radio it works really good but I wanted to make a digital Turner for it maybe with a crystal oscillator but I'm not sure how yet :/ it's to hard to find a variable compasitor
hello sir unfortunately I can't listen the voice . I have tried all the things but I m not getting success sir please help me. I have used 2N2222 transistor one side and the other side I used 2N3904 so can it work sir please reply me fast thank you
Hello, Is there anyone who made this circuit using 2N3904 transistors ??? Did it work with these transistors ?????? Does it need any changes to work with these transistors??? BF494 are no locally available
Dont waste your time dude this type of radio not going to work for everyone because in the US the tower is so much closer to the neighbourhood and having more powerful signal while other countries is different...you will need a special FM radio microchip to make it work like the BK1079. So as you can see many people in the comment failed to make like the one in the video...because i've tried it myself as well nothing work not even a sound but just noise from surrounding.
I used 3904s, and, yeah, it kinda works. It's hard to tune and *very* drifty, so you may hear one station for a few minutes, and then the oscillator drifts off somewhere else on the spectrum. The extra capacitor across the amplifier pins was a necessity for me to get any audible output. If you think of this as the FM equivalent of a very simple crystal radio, you may be happy with the results: the miracle is that it works at all.
sir that 10 kohm vr preset isn't working when I m taking out the screwdriver so what is fault in my circuit and though I m putting screwdriver I can only hear the same noise which was definitely not of radio . please tell me and what is your Facebook profile name please tell me because I want to clear my doubts thank you sue
How are you drawing output from the base of that second transistor where the base is hooked up to the non inverting input of the Op-Amp ?? This part of the schematic does not make sense to me?
If you 'click' on the link in the comment section, you will see the exact schematic I used. The two transistors form a closed loop circuit where the output of the transistor on the right feeds the input of the transistor on the left. The output of the left transistor then feeds the input on the right. The exact frequency seen by the transistors is determined by the incoming radio station signal developed across the L-C tuning circuit.
sir but there is no other way without using trimmer cap? can we change frequency by stretching the inductor? of any one knows answer of my question then please reply. Thank you
Hello - you do have an interesting problem.The heart of the radio is the Tank Circuit, which is the coil and the trimmer (variable capacitor ) in parallel with each other. The values are picked because they will work together (resonate) at the FM signal you want to pick up. One of those components have to change in order to tune into the right signal. The only way to work around this is to put a fixed capacitor where the trimmer goes. 5 or 10 pico farads is a good place to start. And then gently touch the capacitor. The stray capacitance in your finger tips will change the value of the capacitance in the circuit and there is a chance you will pick up a radio signal. The only problem is once you take your hand away, the signal will disappear. There are Resonance Calculators online which will help you figure out what component values you need to select in order to pick up the right channel. The coil, if built properly, has a values of about 250 to 300 Nano Henrys. Here is a link to a calculator: ruclips.net/video/PoSso8Zdfqo/видео.html Good luck and let me know how you do.
sir now I have an problem I m not getting trimmer cap and anyone can also try without it if you can answer. The seller told me that now you have to fit an normal capacitor bread board of certain value and if not works you can change the nearest value of capacitor for getting it to work. so please i will be thankful if sir or anyone other can help me. I need a frequency of 87Mhz to 100Mhz so any one can tell me that how do I make inductor of how much turns of 18 gauge and rolling it on which substance and of which value of capacitor do I buy so that by calculation I can get my above desired value and by changing the capacitor I can get another value.i will be very much thankful if anyone can calculate this and send me a mail or can also comment here so please help me and reply fast .Thank you
sir luckily I got one trimmer cap and now I have an little doubt that where to fit the middle terminal of the trimmer in the circuit so sir please help me with my little doubt fast thank you
Typically, a trimmer cap has three terminals, of which, the the two on ends are connected together. Connect one wire to one end or the other - it does not matter. The second wire is connected to the middle pin.
I hope I can help. The two transistors form a very simple regenerative circuit, where the output of the transistor on the left - at the collector - feeds back into the base of the transistor on the right. Its what is called "positive feedback" The strength of the signal at the base of the left transistor is caused by the injection of the tank circuit - the capacitor and coil in the center. As with any regenerative circuit, as the base current goes up, the current of the collector goes down - that feeds back into the base of the other transistor, increasing the signal gain. Regenerative circuits are a good way to maximize the gain of a circuit.
I doubt it would work. The transistor on the right, from the collector, feeds the input to the transistor on the left at the base. Then the transistor on the left outputs the signal back to the input to the transistor on the right. This is a closed loop signal. The frequency of the signal oscillating back and forth between the two transistor is dependent by the values of the L - C tank circuit, sitting between the collector of the left transistor and VCC. As you change the value of the variable capacitor, the frequency changes. I hope this helps.
@@phs125 No - the two transistors are used for oscillating the fm signal. The angle of the sine wave at the base of the right transistor creates a varying voltage drop at the base which looks like an audio level signal coming from the station you are tuned to. That signal is the sent to the input of the LM386 which does the real amplification of the station's signal.
There are schematics I've seen on the Internet which have just one transistor, and technically it will work, provided you have a strong radio station near you. But remember, this is a very simple radio with very minimal performance capabilities.
I would put a 50k pot in place of the 22k resistor so you can adjust the regeneration. The two transistors behave like a tunnel diode when set to the correct bias.
It is a regenerator circuit. Usually there are more resistors caps and inductors around a single transistor. This circuit has less components, but it works by a virtue of unique combination of parts and supply voltages.
Good job Radio66, just subscribed , are two transistor the same ? can be any one of bf494 bf199 nte229 2n3904 2n2222 ? , I have 2n3904 and 2n2222a 2n2222 ,and indeed it's a lot fun to do
All the transistors mentioned have the same basic characteristics, and I think you could mix two different types, but my preference would be to use the same kind for this circuit.
First thing to do is to make sure the coil and the variable capacitor are close to each other as they feed off of each other to create the right oscillation. Also, experiment with antenna lengths. Start with a foot and then move up to 3 or to six feet. Give these things a try. All the best.
I am just wondering if you would have any idea why when i turn the 10k pot it does not effect the volume? i have followed the schematic perfectly but cannot get anything but really low level static. Tuning the cap also does not effect the sound
Nice work indeed ❤ I would rather be happy if it is at all possible make 1 or transistor amplifier circuit diagram in lieu of op amp LM386 I have a pocket world reciever which uses only one transistor as speaker power output but it's hard to read circuit diagram as it very compact....waiting for reply Thanks above all🙏🙏🙏🇮🇳
My apology for not getting back to you sooner. There are a number of very simple one-transistor circuits available online. The only problem is that with a one-transistor amp, you can only use an earphone. The output is not enough to drive a speaker. To find a circuit, just Google schematic for one simple one-watt audio amplifier. For a transistor, I prefer a 2N2222 but most NPN audio transistors will work. Gook luck
From the datasheet I saw, it can be. The s9018 works over over a high frequency range. I'm not sure about gain. The 2n3904 and the 2n2222 - both very generic - works great, too.
Thanks for the info. I actually had it working - sort of - at about a third of a meter. Anyhow, thanks. I'll try 10 meters ( 33 feet ) next time I experiment with this.
The 9014 and 9013 might work but they are designed for a lower frequency range. That is why I suggested the 2n3904 and the 2n2222. They both have twice the frequency range than the ones you mentioned. The 9014 has an operating range of 150 MHz where as the 2n3904 range is 300 MHz. FM radio operates from 88 to 108 MHz.
+Mohammed HAJHOUJ The LM 386 is designed as an audio amplifier, operating at a small voltage. The LM358 is designed to operate at much larger voltages.. Best to stay with the 386.
Randall Bashta Thanks for info :-) . The question because I salvage a LM358 from old satellite tuner ;-) and don't have an LM386, so I thought that I can make it useful by using it as an amplifier in this radio project
I was able to use the lm358 and it amplify sound but quality was little bite not fine, but i'm ok that the lm386 is done to be an audio amplifier. my idea was to reuse a salvaged lm358 as I didn"t have an lm386.
You are absolutely right. Like any simple radio, it only works with a decent signal in the area. I was able to pick up high powered fm stations about 15 miles away. Still, a lot of fun to experiment with.
Break the connection to the antenna and put the 5pf between the main circuit and the antenna. The capacitor is there to prevent a longer antenna from loading down the circuit. You may have to experiment with longer antennas depending on the power of the FM stations around you. Good luck.
According to Google - Because the collector current of the 2N3904 is 200mA and the collector current of the BC547 is 100mA, you can replace the 2N3904 with BC547 if the load you're driving is less than 100mA, but you can't use BC547 if the load is greater than 100mA
Like all simple circuits circuits, the performance is "iffy". This circuit's ability to work depends party on the antenna and the strength of nearby FM stations. Also, just like a simple diode radio used for AM broadcast reception, the sound quality is limited. But, technically, this circuit will work. The schematic is very similar to others posted on You Tube.
To start with, the antenna picks out the FM signals in the air. The antenna is connected to the tuner which is made up of the coil and the capacitor. The variable capacitor and coil, in parallel with each other, decides what station is passed to the two transistor amplifier circuit below. As the FM signal moves back and forth across the base of the transistor on the right, a slight voltage change is produced across the resistor. This produces a signal which mimics the signal the station is sending. This signal is them amplified by the LM386 which sends the louder signal to the speaker. I hope this helps. I may produce a video on this someday.
Papa Blast be aware of pF capacitors used In this design. Any somewhat buggy connected wire would produce even higher capacitance than this. So make the antenna resonance part as short as possible connected to each other.
Seems like breadboard(or some of them) introduce unwanted capacitance (C) Usually for RF/Radio stuff, it is better to build on PCB or such(protoboard..etc.) freecircuitdiagrams4u.blogspot.com/2014/06/simple-fm-circuit-diagram.html
Double check the pin outs of the transistors: from the front - pin 1 is on left is the emitter, middle pin is the Base and collector is on right pin. Play around with the antenna length, make sure it is long enough. And make, the im 386 is set up for the max gain. Good Luck.
Another fellow has a video similar to mine and perhaps by watching his, this video and help you a little more than mine.His link: ruclips.net/video/VmNlDewXt2MG/видео.htmlood Luck
sir fortunately I can hear the disturbance of radio but can not hear any song sir please help me and please tell your Facebook profile name please reply sir. Thank you
Hi - It sounds like you are making some progress. There are a couple of things you can try to help improve the performance of the radio. You can try different antenna lengths of the antenna. Also you can spread out the coil slightly. And remember, the coil and the trimmer should be close to each other to help in the resonating of the incoming signals. There are plenty of good videos on RUclips to help you understand how an L-C Tank circuit works. They are helpful. Also remember, this is a very simple-crude circuit used for experimentation and learning. A proper FM radio has a more precise tuner and decimator circuit needed to separate the audio signal from the carrier wave. Good luck with this. I am not on Facebook.
LM386 is an Audio Amp www.ti.com/lit/ds/symlink/lm386.pdf Try it, find someone on the net who used it as audio amp duckduckgo.com/?q=lLM324+audio+amp+circuit&t=ffcm&iar=images&iax=images&ia=images
As you can imagine, not having a proper Demodulator circuit, hampers the audio. This type of radio uses the poor-sounding 'slope detection' circuit, not known for quality. Thanks for watching.
There is not a true FM demodulator in this circuit. However, the angle of the RF signal across the transistors creates a changing voltage drop at the base which mimics an audio signal. That distorted signal is then amplified by the LM386. This is known as slope detection. There are other videos on RUclips that use a similar circuit. Easy to make and fun to play with.
sir please i will we very thankful to you if you really please say is this circuit working so that i buy those component please reply fast sir I will very much thankful to you .You can also mail me and please tell me your Facebook account please reply fast sir thank you sir
Yes, the circuit does work. It is a very simple circuit and how well it work depends of where you are - how close an FM station is to you - and how careful you are in assembling this radio. Also, this radio works like any simple radio, like a crystal set: it will work but not great. Feel free to ask me any questions. I am going to post a follow up video soon.
Hi Mario - we have found you need a rather strong FM station in your area for this radio work. It is like an old fashioned crystal radio, not very sensitive. Some guys I talked with also said they had to play with the length of the antenna to get it to work. And some other experimenters spread the coil wires slight a part, opening up the gap. And its worth mentioning that the tuning capacitor should be as close as possible to the coil to help the tuning oscillator process. I hope this helps.
The best way to find such a trimmer cap is on EBAY. That is where I bought my second one. The first one I got from a local electronics parts store here in Massachusetts.
Good job. You explain it in a very understandable format. Keep it up, your awesome!
Love this and congrats ; great job . This year I ' ve managed to obtain similar performance with a different configuration of a twin transistor model and two AA in cascade , thanks for your nice contributions .
I enjoyed your video. You were nice and thorough. I have made one and two AM transistor radios.
This is a regenerative receiver that detects FM by using the slope detection technique in which amplitude varies with frequency. It uses a Franklin oscillator, which is the most simple and easiest oscillator to implement. As a matter of fact, sometimes you can remove either transistor and the circuit still can oscillate! What we need here (to improve) is a way to reduce the oscillation amplitude to improve signal readability (reduce noise); this can be done best by making the 22 k-ohm resistor variable. I would experiment with adding a potentiometer at the input to reduce the amount of signal that comes from the antenna. While this sounds counter-intuitive, it’s the most effective way to improve selectivity of the radio (thus, reducing noise). Reason being: regenerative receivers can amplify with extremely high gain (inferior to only the super-regenerative receivers, also an invention of Armstrong). With too strong of an input, a signal doesn’t make too many loops around the regenerative circuit before output becomes too strong. Consequently its Q is not high and its selectivity suffer (too much noise comes from nearby frequency). Reducing (all) incoming RF signal allows more room (so to speak) to amplify before the total energy reach the ear, this enables higher Q, higher selectivity meaning the ratio of signal of interest over surrounding noise is higher.
All good information. Thanks for taking the time to share the information. I do agree that this is slop detection and you can even remove one of the transistors. At some point I want to try re-doing this video as I did it a number of years ago. Thanks for writing - de N1KRB
Thank you very much for your fast reply sir though it will be not work good but then also if I can hear a little bit then also I will be happy I'm studying in 12 standard but many my teachers told me that it can not work with this simple circuit so I will definitely prove them wrong . I have a great interest in making such projects and good going sir keep more educational projects I will always remember you if it work thank you sir
Thank you very much sir finally I can hear 2 channels. Thank you very much sir .After I tried number of variation I finally got success and thank you again sir upload more educational videos.
can u please share ur details.....i am working on it.......I am besides India.
mohit panjabi video is very perfect but you need to add 5 pico Faraday capacitor before antenna and it would work perfecly if you have fixed circuit properly
thanks for your note.
Good to hear you were able to make the radio. It is a fun-simple circuit. To make a digital control tuner you would need a digital-to-analog IC. A digital keypad puts in a digital number at the input of the chip and an analog voltage is produced at the output to control a varactor, which is a voltage controlled variable capacitor.As the analog voltage is raised or lowered, this produces a change in the capacitanceof the varactor. The varactor operate in parallel with a coil which forms the tuned circuit.There are plenty examples on the internet how this is done. The trick is to find one that works in this situation - and the other trick to find the parts at a decent price. I will do some research and if I find something I will share it with all.
Hello Sir.
I was very surprised because it worked perfectly!
At first I used the lm386 as an amplifier but it made noise so I decided to use one of those amplifiers from china, *_PAM_* or something, and it worked perfectly !!
You are so right, PAM8403 is a great class D amp and it comes cheap on a module
ruclips.net/video/oB-k0tA1G2M/видео.html
duckduckgo.com/?q=PAM8403+Audio+Amplifier+Module&t=ffcm&iax=images&ia=images
www.diodes.com/assets/Datasheets/PAM8403.pdf
TheAstro30 lol
Thank you, your small fm radio receiver circuit was helpful. I am in sri lanka
Is this circuit working in Sri Lanka ?
Hi there, I also reside in Sri Lanka. Does it work?
Brilliant performance .
thanks for sharing, it was very helpful
On the subject of small FM radio receivers, I had a radio from a cap. I think it was solar powered or used button cells. It had 6 transistors and one integrated circuit, among the components. It had an earphone. The circuit itself was very compact. Another FM radio I had was from a promotional giveaway, if I recall. It had 2 transistors and one integrated circuit. Again, the circuit board was very small. It used three triple A, 1.5 volt batteries. It used earbud type headphones. Your circuit looks pretty neat. It's a similar concept to the second FM radio I mentioned. If you lived a hundred miles or kilometers from a major city, I wonder how sensitive these receivers would be. I know that attaching a wire from your FM antenna to your cable outlet for your T.V works a charm to get distant FM radio stations.
The first FM radio was part of a ball cap.
yeah sir you may be right I have an Fm pocket radio in which sometimes when I touch the antenna it get works properly so on touching the capacitor I may get the different frequency and now I will surely try this one but when today I was going to buy transistor to my local shop he also told me that we can not make a radio from this much simple circuit he also told me that I will just waste my money as this useless circuit won't work but then also I bought those transistor and said to him though I will waste my money but I have an trust on this channel and I think that it's not fake and I will do my best. Thank you
Good Job, thanks for sharing
Great video! Thanks for uploading this
thanks for letting me know
In the actual demonstration, I'm using a small speaker, even though the schematic shows headphones. SO, yes, you can used a speaker.
Very nice!!
Thank you very much for this circuit. I assembled it and it worked quite well at short range. Do you have any tips on increasing the sensitivity so it works better at longer range?
The only thing I can suggest is to play with the antenna length. As you can see, it is a very basic circuit design with very few options for improvement.
Good Luck
I'm trying to make with the things on hand and none of them are the same 😂 it's gonna fail
@@daddyplankton5855 can i use c945 ,s9018 Transistors insted
Lots or fun and a good explanation, thanks!
Thanks for watching and thanks for your comment - 73
esta precisando de videos como esses na internet parabens
Hey, did anyone make it work with 2N2222 or 2N3904? It's inpossible to get BF transistors where I live.. I've been trying this layout out with the the wrong (4-10pf) variable cap and have had no luck of making it work. Gonna try it all out today with the 20pf varicap again.
Any extra tips for assembly n such?
Thanks!
Will it work if I use a ready made lm386 audio amp
how did you make the antenna sir. TYIA. your explanation is very clear aside from the antenna
Thanks for your question. My radio worked differently in different locations. Down in my basement, I clipped on a wire of 1 foot it that worked for me. However, up in the kitchen ( where I shot the video) I used a transistor radio telescopic antenna which was mounted vertically in a wood block. This is something one has to experiment with.
Thank you very much for your fast response sir. Have a nice day.
www.wikihow.com/Make-an-FM-Antenna
Hi, I would like to build this circuit for my school project. I saw your other video about the antenna booster and I would like to use that circuit on this one. Can I connect that circuit to this one on a single battery?
+CyberBoy8799 Yes and no. I've not tried it before, but in theory, it should work. However, the value of the choke needs to change on the antenna booster to accommodate the frequency of the FM band. Follow this link for more info on the booster:www.seekic.com/circuit_diagram/Amplifier_Circuit/Active_Antenna_for_AM_FM_SW.htmlTips on making the radio: 1) play with the length of the antenna - every situation requires a different size - 2) keep the coil and the tuning capacitor close to each other (they feed off of each other) - 3) best to use a tuning capacitor with a knob because stray capacitance from fingers, coming close the tuner, will effect the performance and 4) don't forget the 10ufd cap between pin 1 and 8 on the LM386 needed to boost the output.Good luck
It obviously detects FM but if that was the best signal quality you could get, it still needs work.
Good job on the video. Maybe you could show us how to improve the design.
Do you think the poor sound quality is due to the speaker or the minimalist nature of the circuit?
I know the lm-386 produces fairly nice sound quality, so it's probably not that.
Excellent video❤very good🇧🇷😉👍 👏👏👏
Thanks for your comment
Howdy.
Yes. That circuit works quite nicely. It is a slope regenerative circuit . One might use a 47k pot. to adjust regeneration for best sound quality instead of the fixed 22k resistor.
Another addition would be to use a low pass RC filter before the op. amp. to correct the FM high audio bands boosting. The RC time constant is 75 us in USA and 50 us in Europe.
The two transistors form an oscillator that uses the incoming signal to uphold oscillation. Detection appears as current changes.of the oscillator as it fights the FM deviation.
Regards.
Thanks for taking the time to reply - all good suggestions. I think you're right. As the FM slope changes, the voltage change it produces at the input of the .22 ufd cap, produces the audio signal of of the FM station being tuned in. The next time I play with this circuit, I'll put in a pot in place of the 22k resistor. Again, thanks for your suggestions and remarks.
@@rbashta Howdy again.
I forgot one thing. One might connect a 4k7 resistor in series with the pot. to avoid accidently turning the pot too low which would destroy the oscillator transistors.
May I advertise my blog: "1. Table of blogs. Blogiluettelo." which is a list of blogs. I have tried several circuits of FM detectors. The blog circuits have all proven to work
Regards.
Do you know what a reason would be for deep buzzing noise coming from speaker? its almost as if the coupling capacitor does not do its job and the output of the op amp is constant dc current??
Use a 9v battery with a 5v voltage regulator(7805) or LM317 set it to work at 4.5 volts
Or use 3 x AA or AAA ...etc.
Sometimes something from AC or Power Supply causes problems.
And run it outside away from different electrical/electronic devices.
Thanks for you
I made an am radio it works really good but I wanted to make a digital Turner for it maybe with a crystal oscillator but I'm not sure how yet :/ it's to hard to find a variable compasitor
+pier shaw I find EBAY is the best resource
hello sir unfortunately I can't listen the voice . I have tried all the things but I m not getting success sir please help me. I have used 2N2222 transistor one side and the other side I used 2N3904 so can it work sir please reply me fast thank you
Hello, Is there anyone who made this circuit using 2N3904 transistors ??? Did it work with these transistors ?????? Does it need any changes to work with these transistors??? BF494 are no locally available
Same question dude
Dont waste your time dude this type of radio not going to work for everyone because in the US the tower is so much closer to the neighbourhood and having more powerful signal while other countries is different...you will need a special FM radio microchip to make it work like the BK1079.
So as you can see many people in the comment failed to make like the one in the video...because i've tried it myself as well nothing work not even a sound but just noise from surrounding.
yes i tried and it doesnt work im so disappointed !
I used 3904s, and, yeah, it kinda works. It's hard to tune and *very* drifty, so you may hear one station for a few minutes, and then the oscillator drifts off somewhere else on the spectrum. The extra capacitor across the amplifier pins was a necessity for me to get any audible output. If you think of this as the FM equivalent of a very simple crystal radio, you may be happy with the results: the miracle is that it works at all.
Neodiy.c0m
sir,this fm radio works with transistors listed with a long ridiculous coaxial cable antenna ,try it:
sir that 10 kohm vr preset isn't working when I m taking out the screwdriver so what is fault in my circuit and though I m putting screwdriver I can only hear the same noise which was definitely not of radio . please tell me and what is your Facebook profile name please tell me because I want to clear my doubts thank you sue
How are you drawing output from the base of that second transistor where the base is hooked up to the non inverting input of the Op-Amp ?? This part of the schematic does not make sense to me?
If you 'click' on the link in the comment section, you will see the exact schematic I used. The two transistors form a closed loop circuit where the output of the transistor on the right feeds the input of the transistor on the left. The output of the left transistor then feeds the input on the right. The exact frequency seen by the transistors is determined by the incoming radio station signal developed across the L-C tuning circuit.
Thank you and yes 👍🏻 I managed to figure that part out, circuit works great.
Thanks for letting me know. Good to hear.
sir but there is no other way without using trimmer cap? can we change frequency by stretching the inductor? of any one knows answer of my question then please reply. Thank you
Hello - you do have an interesting problem.The heart of the radio is the Tank Circuit, which is the coil and the trimmer (variable capacitor ) in parallel with each other. The values are picked because they will work together (resonate)
at the FM signal you want to pick up. One of those components have to change in order to tune into the right signal.
The only way to work around this is to put a fixed capacitor where the trimmer goes. 5 or 10 pico farads is a good place to start. And then gently touch the capacitor. The stray capacitance in your finger tips will change the value of the capacitance in the circuit and there is a chance you will pick up a radio signal. The only problem is once you take your hand away, the signal will disappear. There are Resonance Calculators online which will help you figure out what component values you need to select in order to pick up the right channel. The coil, if built properly, has a values of about 250 to 300 Nano Henrys. Here is a link to a calculator: ruclips.net/video/PoSso8Zdfqo/видео.html
Good luck and let me know how you do.
sir now I have an problem I m not getting trimmer cap and anyone can also try without it if you can answer. The seller told me that now you have to fit an normal capacitor bread board of certain value and if not works you can change the nearest value of capacitor for getting it to work. so please i will be thankful if sir or anyone other can help me. I need a frequency of 87Mhz to 100Mhz so any one can tell me that how do I make inductor of how much turns of 18 gauge and rolling it on which substance and of which value of capacitor do I buy so that by calculation I can get my above desired value and by changing the capacitor I can get another value.i will be very much thankful if anyone can calculate this and send me a mail or can also comment here so please help me and reply fast .Thank you
Hey will there be any problem if I use 741 op-amp?
Both the 741 and 386 are linear amps but the 741 requires both a positive and negative power supply.
sir luckily I got one trimmer cap and now I have an little doubt that where to fit the middle terminal of the trimmer in the circuit so sir please help me with my little doubt fast thank you
Typically, a trimmer cap has three terminals, of which, the the two on ends are connected together. Connect one wire to one end or the other - it does not matter. The second wire is connected to the middle pin.
Useful
I hope I can help. The two transistors form a very simple regenerative circuit, where the output of the transistor on the left - at the collector - feeds back into the base of the transistor on the right. Its what is called "positive feedback" The strength of the signal at the base of the left transistor is caused by the injection of the tank circuit - the capacitor and coil in the center. As with any regenerative circuit, as the base current goes up, the current of the collector goes down - that feeds back into the base of the other transistor, increasing the signal gain. Regenerative circuits are a good way to maximize the gain of a circuit.
What happens if we add a 3rd transistor?
I doubt it would work. The transistor on the right, from the collector, feeds the input to the transistor on the left at the base. Then the transistor on the left outputs the signal back to the input to the transistor on the right. This is a closed loop signal. The frequency of the signal oscillating back and forth between the two transistor is dependent by the values of the L - C tank circuit, sitting between the collector of the left transistor and VCC. As you change the value of the variable capacitor, the frequency changes. I hope this helps.
@@rbashta thanks, I thought it was just amplifying the signal.
@@phs125 No - the two transistors are used for oscillating the fm signal. The angle of the sine wave at the base of the right transistor creates a varying voltage drop at the base which looks like an audio level signal coming from the station you are tuned to. That signal is the sent to the input of the LM386 which does the real amplification of the station's signal.
If i have to use one transistor, can i remove one transistor in the middle? If i can, how?
There are schematics I've seen on the Internet which have just one transistor, and technically it will work, provided you have a strong radio station near you. But remember, this is a very simple radio with very minimal performance capabilities.
sir unfortunately the circuit is not working by me now what I do please guide me sur
I would put a 50k pot in place of the 22k resistor so you can adjust the regeneration. The two transistors behave like a tunnel diode when set to the correct bias.
Tunnel diodes are very expensive, this is a poor man's tunnel diode.
That's good information. ..I'll give it a try.
This is weird. I don't see how it detects, ie, converts FM to an audio output. I'm guessing its off-tuning a bit.
It is a regenerator circuit. Usually there are more resistors caps and inductors around a single transistor. This circuit has less components, but it works by a virtue of unique combination of parts and supply voltages.
Good job Radio66, just subscribed , are two transistor the same ? can be any one of bf494 bf199 nte229 2n3904 2n2222 ? , I have 2n3904 and 2n2222a 2n2222 ,and indeed it's a lot fun to do
All the transistors mentioned have the same basic characteristics, and I think you could mix two different types, but my preference would be to use the same kind for this circuit.
@@briancheshire1113 Thanks for the reply Brian Cheshire, I will try .
sir i made this circuit but it gives noise only when i touches with my finger at the input end of lm386n-1 beside this it is not working.
First thing to do is to make sure the coil and the variable capacitor are close to each other as they feed off of each other to create the right oscillation. Also, experiment with antenna lengths. Start with a foot and then move up to 3 or to six feet. Give these things a try. All the best.
I am just wondering if you would have any idea why when i turn the 10k pot it does not effect the volume? i have followed the schematic perfectly but cannot get anything but really low level static. Tuning the cap also does not effect the sound
I hope to share the schematics soon afterwards .
Nice work indeed ❤
I would rather be happy if it is at all possible make 1 or transistor amplifier circuit diagram in lieu of op amp LM386
I have a pocket world reciever which uses only one transistor as speaker power output but it's hard to read circuit diagram as it very compact....waiting for reply
Thanks above all🙏🙏🙏🇮🇳
My apology for not getting back to you sooner. There are a number of very simple one-transistor circuits available online. The only problem is that with a one-transistor amp, you can only use an earphone. The output is not enough to drive a speaker. To find a circuit, just Google schematic for one simple one-watt audio amplifier. For a transistor, I prefer a 2N2222 but most NPN audio transistors will work. Gook luck
നന്ദി സാർ
i have a question again can i use a s9018 transistor?
From the datasheet I saw, it can be. The s9018 works over over a high frequency range. I'm not sure about gain.
The 2n3904 and the 2n2222 - both very generic - works great, too.
which varactor did you buy to use here?
I bought a variable capacitor from EBAY which ranged from 2 to 20 pf.
thank you!
Standard you tube circuit, only works with a 10 meter aerial .
Thanks for the info. I actually had it working - sort of - at about a third of a meter. Anyhow, thanks. I'll try 10 meters ( 33 feet ) next time I experiment with this.
Can I use s9014,s9013 transistor???
The 9014 and 9013 might work but they are designed for a lower frequency range. That is why I suggested the 2n3904 and the 2n2222. They both have twice the frequency range than the ones you mentioned. The 9014 has an operating range of 150 MHz where as the 2n3904 range is 300 MHz. FM radio operates from 88 to 108 MHz.
Thank you for your comments. I look forward to your own schematics.
Hi, can I use LM358 in place of LM386?
+Mohammed HAJHOUJ The LM 386 is designed as an audio amplifier, operating at a small voltage. The LM358 is designed to operate at much larger voltages.. Best to stay with the 386.
Randall Bashta
Thanks for info :-) . The question because I salvage a LM358 from old satellite tuner ;-) and don't have an LM386, so I thought that I can make it useful by using it as an amplifier in this radio project
+Mohammed HAJHOUJ LM358 is a ampop and LM386 is a audio amplifier! What's better for you? An ampop or a audio amplifier?
I was able to use the lm358 and it amplify sound but quality was little bite not fine, but i'm ok that the lm386 is done to be an audio amplifier. my idea was to reuse a salvaged lm358 as I didn"t have an lm386.
With LM358 make a good amplifier circuit!!
This radio would only work if the radio signal is quite strong within area....further than that you will need PLL and demodulation
You are absolutely right. Like any simple radio, it only works with a decent signal in the area. I was able to pick up high powered fm stations about 15 miles away. Still, a lot of fun to experiment with.
At 3:55 how do you hook the 5 pico cap ?
Break the connection to the antenna and put the 5pf between the main circuit and the antenna. The capacitor is there to prevent a longer antenna from loading down the circuit. You may have to experiment with longer antennas depending on the power of the FM stations around you. Good luck.
Radio66 Great answer. Thank you
Can i use bc547 npn ?
According to Google - Because the collector current of the 2N3904 is 200mA and the collector current of the BC547 is 100mA, you can replace the 2N3904 with BC547 if the load you're driving is less than 100mA, but you can't use BC547 if the load is greater than 100mA
This circuit work?
Like all simple circuits circuits, the performance is "iffy". This circuit's ability to work depends party on the antenna and the strength of nearby FM stations. Also, just like a simple diode radio used for AM broadcast reception, the sound quality is limited. But, technically, this circuit will work. The schematic is very similar to others posted on You Tube.
sir please reply
I am a beginner Can you define the circuits Thanks
To start with, the antenna picks out the FM signals in the air. The antenna is connected to the tuner which is made up of the coil and the capacitor. The variable capacitor and coil, in parallel with each other, decides what station is passed to the two transistor amplifier circuit below. As the FM signal moves back and forth across the base of the transistor on the right, a slight voltage change is produced across the resistor. This produces a signal which mimics the signal the station is sending. This signal is them amplified by the LM386 which sends the louder signal to the speaker. I hope this helps. I may produce a video on this someday.
@@randallbashta6957 I think it's a Superheterodyne circuit. If it is, can the mixer and oscillator be specified Thank you
please reply
what's indutance of inductor?
+Tiago NET According to an online inductance calculator, it is about .05 uH.
50nH ok!!!
+Tiago NET Yes - .05 uH is 50nH. I do see them available commercially in 43 and 56 nH.
ok
I tried that circuit on a breadboard and it didn't work.
Papa Blast be aware of pF capacitors used In this design. Any somewhat buggy connected wire would produce even higher capacitance than this. So make the antenna resonance part as short as possible connected to each other.
Seems like breadboard(or some of them) introduce unwanted capacitance (C)
Usually for RF/Radio stuff, it is better to build on PCB or such(protoboard..etc.)
freecircuitdiagrams4u.blogspot.com/2014/06/simple-fm-circuit-diagram.html
im trying with 2n3904 and it doesnt work !!! 3 attempts !!!
Double check the pin outs of the transistors: from the front - pin 1 is on left is the emitter, middle pin is the Base and collector is on right pin. Play around with the antenna length, make sure it is long enough. And make, the im 386 is set up for the max gain. Good Luck.
@@rbashta thanks but i tried it all im not sûre i can do this its really frustrating
Another fellow has a video similar to mine and perhaps by watching his, this video and help you a little more than mine.His link: ruclips.net/video/VmNlDewXt2MG/видео.htmlood Luck
You sound exactly like bat man
sir fortunately I can hear the disturbance of radio but can not hear any song sir please help me and please tell your Facebook profile name please reply sir. Thank you
Hi - It sounds like you are making some progress. There are a couple of things you can try to help improve the performance of the radio. You can try different antenna lengths of the antenna. Also you can spread out the coil slightly. And remember, the coil and the trimmer should be close to each other to help in the resonating of the incoming signals. There are plenty of good videos on RUclips to help you understand how an L-C Tank circuit works. They are helpful. Also remember, this is a very simple-crude circuit used for experimentation and learning. A proper FM radio has a more precise tuner and decimator circuit needed to separate the audio signal from the carrier wave. Good luck with this. I am not on Facebook.
Make the circuit board for sale or make it a kit
Thanks for your comment. I've had several suggestions, regarding making a kit. I will further look into this.
@@rbashta If you make this into a kit let your fans no,thanks for your video
Can I use LM324 op. amp. instead of LM386 op. amp. ??
LM386 is an Audio Amp
www.ti.com/lit/ds/symlink/lm386.pdf
Try it, find someone on the net who used it as audio amp
duckduckgo.com/?q=lLM324+audio+amp+circuit&t=ffcm&iar=images&iax=images&ia=images
Коллекторы гальванически соединены с базами, в эмитерных цепях ничего нет при этом. Чудеса. Резистор на 22 к не даёт транзистора сгореть.
The resister is used to drop the voltage and to limit the current. Thanks for checking in
Oh god it sounds horrible. VERY GOOD!
As you can imagine, not having a proper Demodulator circuit, hampers the audio. This type of radio uses the poor-sounding 'slope detection' circuit, not known for quality. Thanks for watching.
Je l'ai fabriqué, un seul transistor suffit sur les deux
Merci de me le faire savoir. J'en ai entendu d'autres utiliser un seul transistor.
*power amp
INDUCTOR VALUE = 0,15uH
Great, so that is like 150 nH
thanks
Try this
freecircuitdiagrams4u.blogspot.com/2014/06/simple-fm-circuit-diagram.html
the TR exploded .....
+yeodakyum Make sure you check your data sheet on the transistor. The BF
series of xisters have a different pin out than the 2N series.
FM? Where is frequency demodulator?
There is not a true FM demodulator in this circuit. However, the angle of the RF signal across the transistors creates a changing voltage drop at the base which mimics an audio signal. That distorted signal is then amplified by the LM386. This is known as slope detection. There are other videos on RUclips that use a similar circuit. Easy to make and fun to play with.
sir please i will we very thankful to you if you really please say is this circuit working so that i buy those component please reply fast sir I will very much thankful to you .You can also mail me and please tell me your Facebook account please reply fast sir thank you sir
Yes, the circuit does work. It is a very simple circuit and how well it work depends of where you are - how close an FM station is to you - and how careful you are in assembling this radio. Also, this radio works like any simple radio, like a crystal set: it will work but not great. Feel free to ask me any questions. I am going to post a follow up video soon.
Diagram not clear.
Click on the link posted below the video
lol
freecircuitdiagrams4u.blogspot.com/2014/06/simple-fm-circuit-diagram.html
Nothing was heard !!!
Hi Mario - we have found you need a rather strong FM station in your area for this radio work. It is like an old fashioned crystal radio, not very sensitive. Some guys I talked with also said they had to play with the length of the antenna to get it to work. And some other experimenters spread the coil wires slight a part, opening up the gap. And its worth mentioning that the tuning capacitor should be as close as possible to the coil to help the tuning oscillator process. I hope this helps.
There are much better designs for FM 1 transistor circuits that work better than this one. Do some more research.
sir please reply
The best way to find such a trimmer cap is on EBAY. That is where I bought my second one. The first one I got from a local electronics parts store here in Massachusetts.