How a Crystal Radio Works
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- เผยแพร่เมื่อ 29 ส.ค. 2012
- Full details of how a crystal radio works, right down to the electron level.
We start with a demonstration of all the parts in action, showing how the radio waves interact with the antenna and antenna coil to produce a fluctuating magnetic field, which induces electron flow in the tuning coil, which works with the tuning capacitor, which is followed by the diode and crystal earpiece. We talk about why a leaky germanium diode is needed with this particular circuit or how a bypass resistor can be used instead.
That's followed by how the tuning is done using a tuning coil in parallel with a tuning capacitor, which together are tuned to a resonant frequency the same as the radio frequency by adjusting the coil's inductance and the capacitor's capacitance.
Then we show how a radio wave is formed from a microphone's audio wave using amplitude modulation (AM). This then shows how the diode is necessary for converting the radio wave back to an audio wave for use by the earpiece or speaker.
Next we discuss selectivity versus sensitivity and why a separate antenna coil is used.
An finally we show a few other crystal radio circuits.
Thanks to the following for reviewing development versions of this video:
Slovenija12345 of / slovenija12345
and
Charles Wenzel of www.techlib.com/electronics/cr...
See also...
How to Make/Build a Crystal Radio video, the radio explained in this video:
• How to Make/Build a Cr...
Crystal Radio Troubleshooting and Tips video:
• Crystal Radio Troubles...
How to Make an Amplifier for a Crystal Radio Earpiece video:
• How to Make Amplifier ...
Make a Crystal Radio Coil with Taps video:
• Make a Crystal Radio C...
There's also a crystal radio page on my website:
rimstar.org/equip/crystal_radi...
3D modelling and 3D animation done using Blender 2.63.
To follow me on Twitter:
/ rimstarz
rimstar.org - วิทยาศาสตร์และเทคโนโลยี
Today was my birthday. I’m 75. I started listening to crystal radios when I was 9 or 10 years old. I became an mechanical engineer. This video gave the first practical understanding of how a crystal radio works. What a great birthday present. Thanks. You know your audience.
Many years later it's still the best explanation of how a crystal radio works on TH-cam.
Thank you! I finally understand how a crystal radio works after 50 years!
Yeah, that's a deliberate requirement I set when making all my explanations, that I show the thing working at as low level as practically possible so that there's little left to the imagination. Words and static diagrams play a part, but seeing the electrons, electromagnetic fields, radio waves, heat flow, ... makes how it works blatantly clear.
A great presentation! ( Only wish my hearing loss could better accept a slower commentary. No criticism intended.).
I'm an artist with an interest in learning about electricity/tech as a hobby and you make it completely possible for me! Much easier than some books I've bought to teach myself. Thank you!
This was incredible. Thank you Sir
L0p
0
Finally a video that I can wrap my head around to understand Radio. A Million thumbs up. Thank you for taking the time to make such excellent tutorials.
This is the BEST crystal radio explaination I have ever seen.
Outstanding in all categories...!
Excellent graphics. Thanks
You're welcome! It was a pleasure being able to make this one, mostly because to do it I had to learn the pieces I didn't know. I'm glad you liked it. Thanks!
UTTERLY BRILLIANT PRESENTATION!! You sir should win the Nobel Prize for the best explanation and presentation ever.
amartinjoe, As recipient of the 2008 Nobel prize for brain surgery by kickboxing, I'd like to second that and vouch for him at the next committee hearing.
Brain surgery by kickboxing? What. I did not understand this joke?
X No joke. It might seem counter-intuitive at first, but once you acquire the right skill set, kickboxing is actually the least intrusive, and safest, form of brain surgery. I pioneered it, which in part earned me the Nobel prize.
+Daniel Smedegaard Buus Yeah and magic is real
amartinjoe
The radio gets its power from the radio waves themselves. No batteries or other power source is required.
Thanks , that's the reason why I came here but watched the whole thing because of the incredible presentation.
Came here for the same reason about radio waves self powering
Well it is electricity after all
In other words, “wireless electricity”.
ั
The diode is for converting the radio wave back to the original audio wave, as is said at 10:20 in the video and explained in the section before that. For the antenna, I showed that in my How to Make a Crystal Radio video. I just used one of more 15 foot longs wires in parallel, connected where the antenna goes in the circuit. Depending on how close you are to radio stations you may need longer. 15 feet is actually pretty short.
Thank you sir, answering all the questions in less than 13 minutes
Thank you for publishing the first description of how a AM radio works that I can truly understand. Much appreciated.
I made my first crystal radio around 1960. This is the first time I have heard a good explanation of how it worked!
We've continued this in private messages for more room but for the benefit of others, larger diameter plays a part when you get into loop antenna coils. Those are crystal radios where a large diameter coil (1 1/2 feet in diameter for example) is used as both the coil and the antenna. You can see one of these in my "Portable Crystal Radio using Loop Antenna and Pizza Box" video.
This is the video I wanted when I searched “how does a radio work”, thank you! Glad it came up in my recommendeds .
When I was six or seven year old the farther of my friend made a crystal set for his daughter, some times I was aloud to listen and I can remember how amazing it was to me, until today I had no idea how it worked.
Thank you for making this video.
This is the first explanation I have ever seen that made clear the basis of radio. All others seem to be interested in displays of genius. You sir have a new subscriber.
I've been looking for an introduction
to radio like this.absolutely brilliant, thank you.
For 27 years I've been looking for this video. Thank you sir. Thank you. You have enlightened my brain!
I've never seen such a wonderful explanation in my entire life. Big congratulation from Italy. Answered any of my questions and explained a lot more.
Did you know that you're the only one with a video that talks about how radio waves interact with radios? There is not a single video explaining exactly how radios word with detail.
Right?
I love this low level stuff, and the way the electrons flow and interact with things is really what makes me go "oh, that's why". It scratches that "it's just how it works, don't ask why, *asks why* " itch.
I recommend the BCC Documentary "The Story Of Electricity"
@@aprisonerscinemastephenmur6932 thanks for that mate❤️👍🏻
sahroon sah
Wow, so well explained and illustrated. We had to build a crystal radio in an electricity class I took in high school many many years ago. Thanks for the video!
I started this video with numerous questions but you anticipated and answered them all. Such a true educator!
Thanks, Andrew. A lot of work went into this, so I'm glad for your feedback.
-Steve
Hi, great video, despite someone always has something to say, anything that goes towards learning is a good thing.
Actually crystal receivers CAN detect FM, usually nearby local powerful FM stations, I have a couple of videos showing this.
It is called "slope detection, when tuning is slightly off the centre frequency of the station, and as the frequency modulated carrier goes in and out of the radio's resonant frequency, an audio signal similar to the original modulation is made.
just incredible educational material, thank you for the production.
WOW... I made my first crystal radio back in 1972 and it`s the first time I really understand what the diode is there for. No one ever explained it the way You did... FANTASTIC... I`m gonna build one again and use my DSO to look at the different frequencies in the circuit. Thanks a lot here from Denmark!
I learned this as a young man in the Army, but could never actually build one. Now, I think I could build one from memory. Great presentation!
My pleasure. I try to go as deep as I can. Thanks for watching them!
I attended an electronics school in the U.S. Air Force for nearly a year back in the dark ages when the term Hertz was not used (CPS) and we had digital vacuum tube circuits. I have watched just a few of your videos, and had you been my USAF instructor, the school could have been half as long. Your use of animation and excellent easy to understand descriptions make otherwise complex processes very simple. I subscribed, and plan to follow all of your videos. Thank you!!!
Excellent animation explanation.
I made a crystal radio in 8th grade my electronic instructor with Mr. Johnson at Hill Junior High. I had forgotten had it all worked .
Thanks for the wonderful refresher course in its basic operation, with the added electronic lingo and insight.
Thank you. Yours is the only video I've seen that tells the "why" radio works rather than just a list of parts and where they go.
Man you're awesome. I'm an electronic technician but noone ever taught me that way. I had to deduce how some stuff works and know just enough to get my job, I'm basically a repairman.
Thank you very much for your work, you're amazing, keep it up.
I'm sharing this video but I'm afraid my brazilian laymen friends will have difficulties understanding your explanation, even thought you spoke clearly and the animations were great.
That's because you're reading quite fast. I have no problem with it since I already have some understanding but most people don't.
Anyway, thank you very much.
Thanks for your fine, simple, yet considerably informative presentation. It reminds me of my first days of experimenting with radio. This led me into the study of ft transistors which were just then coming on the market. I did a nice science experiment and won a ribbon at school. Quite a thrill for an 11 or12 year old. I still like crystal radios and have some examples left to show grandchildren when n they are able to Comprehend. This eventually led me to get my ham radio license at age 14. Still have it and many more electronic items at 71, following a career in electronics. Keep up the good work !!
...we have a LOT in common-(!)
Very straightforward and attention capturing.
No mentioning of confusing terminologies.
Glad to hear it! Thanks for the feedback.
Man that was awesome. Do more. Great job.
Man, thax for your very detailed explanation!
It's hard to find such an explanation.
You helped me a lot :)
The foxhole radios are basically the same as the one I describe in my video but without the ability to tune intro radio stations using the second coil and the variable capacitor. I think it is possible to tune the foxhole a little using the pencil on the razor. Since there is only one coil there is more overlap of stations, unless you have just one really strong one. The pencil and razor are the diode. I'm glad you found this video helpful! Thanks for the feedback. And I'm from Ottawa, Canada.
I cannot imagine a more thorough or clearer explanation! You've done an excellent job of presenting several difficult concepts in simple, easily understood terms. Well done! Thanks for the effort you put into this.
I'm curious, how long did it take to do the modeling and animations in blender?
One of the best tutorials on TH-cam! Thanks!
One of the best descriptions of the functionality of a circuit! Great work and thanks so much for sharing!
This is the best description of how a radio works that I have ever seen. I plan to use this with my students when we cover circuits and waves
I really hope you continue this series, it's what I was looking for in terms of explanations as to how things work in circuits like this radio. I wouldn't mind learning how other things work this clearly either, this low level is really what makes it click for me, oddly enough.
Heck, I wouldn't mind if you went over formulas and stuff too, like "so and so discovered this, and turned it into a formula _____ where ___ is ____, and this is basically just * some epxlanation of the electrons interacting * in notation form"
Either way, I am in awe. Great stuff!
Update , about AM = Amplitude Modulation why and how.
This is the best explanation I 've ever heard !
I think you're gonna inspire me with this, about mathematics.... Thank you;
That's awesome.
Many people is able to build a crystal radio. But few people is able to explain so clearly how it works.
Thank you.
Thanks! And it's my pleasure. For a 12 minute video I was worried it was too long and dragged out, but I guess that's what happens when you watch it over and over while working on it. :) I'm glad to hear it works.
I am speechless..great work..
I'm currently in the process of watching all your videos and I must say. "DUDE YOU ROCK"!!!!!!! Thanks for all of the great videos, your hard work and time are greatly appreciated.
Thanks! I'm glad you're enjoying them. Thanks for watching!
I just randomly stumbled across your videos today, and they are fantastic. I've never in my life felt like I needed to make a crystal radio but now I think I have to
Thanks for this video. When I was about 14, my parents bought me a radio-shack experiment kit for Christmas. The crystal radio design worked and my mother was amazed. This was the only time she ever seemed impressed with me. I was so moved by her reaction that i later got a BS degree in electrical engineering. While i did take the class on radio theory, I don't recall them explaining what the diode was for. After these 40 years, I might have just forgotten but it is certainly a treat to hear that old circuit explained so well as your video does.
Fascinating stuff! This helps a lot.
Your work here is just wonderful. 35 years ago I was teaching a high interest physics class at Endeavour HS in Sydney AU. I would just love to do it all over again with your chnl as a course syllabus. We'd have a ball and the learning would go over the top. Keep up the good work. I'm sure that you are touching many minds and contributing to the understanding of physics.
Crean en Jesús Cristo y tendrán vida eterna y paz entreguénce a Jesús Cristo ahora mismo en oración Dios les bendiga
Les invito a una iglesia evangélica
Wow, what a clear explanation of how the receiver converts the radio wave to audio! Thank you.
I have been building crystal radios with my four boys for some years and I wish I had this video back when we started. Most excellent. Thanks.
Crean en Jesús Cristo y tendrán vida eterna y paz entreguénce a Jesús Cristo ahora mismo en oración Dios les bendiga
Les invito a una iglesia evangélica
Best explanation ever. Thank you Rimstar.org! Nowhere in the net is there anything up to this clarity level. Incredible performance.
I just want to thank you for your incredible teaching skills. I am getting my kids involved in electronics and can not thank you enough for these amazing videos. God speed.
Thank you so much for your simple explanations which take it to the core of the "problem". Keep up the good job!
Wow! I'm happy to hear it! Your feedback like this makes it worthwhile.
I guess you've seen the video starting at around 10:42 and are wondering why the Earth is a good ground? It's such a large object that it's easy to take electrons from it since it has so many, and it's easy to give it electrons. If you try to give electrons to a small object, it will quickly become strongly negatively charged and repel any more electrons. But it would take more electrons than you can provide before you strongly charge the Earth ground, even if it's just your backyard.
I know I'm seven years late, but you managed to make me understand something with this one comment that I never was never able to grasp before. Thank you.
Ooops. Sounds like now I need to make a History of Crystal Radios video! :) The "crystal" in Crystal Radio refers to the days when an actual rock made of crystalline galena was used as the diode. A wire with a sharp point would be carefully pressed against the crystal and if the location and pressure was just right, the combination would act as a diode. In the early days, magnetic earphones were used instead of piezo crystal earpieces. Some hobbyists still use both today.
That's how we did it in the '60's. We even hand made everything; basically just snipped tin coffee can, copper wire, blank toilet roll, speaker, and a crystal rock.
I followed my brother's Club Scout handbook on how to make a Crystal Radio.
Thanks for the memories, have to share with my grandchildren.
@@thurmanwatson5954 I'm trying to build a radio like that, very "rude" with a real piece of Crystal, but I can't find a single project on how to do It. Can somebody help me? I have a lot of white quartz at home and I wanna use it
@@Alburx I’m sure there’s something out there best of luck to you
@@Alburx No silicon. It is best to use a germanium diode, which you will probably only buy for advertisement, or to make galena - the instructions are on the internet. It is also possible to use lead sulphide (in the crystalline state), carborundum, copper oxide, zinc oxide, pyrite, etc. as a detection diode. Curious old detectors also include a flame detector or an electrolytic one (I will not explain their function). I recommend period high-ohm headphones (2-4k), which you buy for an advertisement. There are many schemes of crystals on the Internet. However, before you build a crystal, I must remind you that the crystal processes amplitude modulation. If there is only FM in your area, you do not need to build a crystal. :)
@@DL-kc8fc so the Crystal Is only for AM and not FM so the radio frequencies are not processed by the Crystal diode, cannnot listen to radio FM with a Crystal based radio right?
Probably the best explanation available on line or off line! Many thanks for going to such a length and sharing your knowledge with the world.
Thanks! I am fairly proud of this one so I'm glad to hear others are enjoying it too.
I always had a life long fascination with the crystal radio.since my first encounter with a Remco slide tuning set of the 1960,s and my own RadioShack Science Fair set from the 70,s Over the years I have built dozens of crystal radios AM, shortwave, even one that picks up CB radio. Your video is a well made description on the functions of the crystal set.
You r amazing...the best peice on crystal..I want to build a new one yet again for my son...Cheers...!!!
Thanks. I'm glad you like it. And better yet, build one _with_ your son. I'm sure he'll enjoy it. See my Crystal Radio playlist on my channel home page. I've plenty of building instructional videos too. Enjoy!
Nice animations and descriptions. I like how you quantify the tradeoffs of circuit design and some of the subtle characteristics that provide functional results such as the crystal earphone and diode leakage. Have you ever derived the speed of the actual electrons that flow? I was surprised to see that they actually move pretty slowly but the resulting field effect is what we perceive as fast; approaching C. Reality is subtle. Thanks, Bob
Electrons don t flow (from one side to another). Electrons stay with there atom, but they will transfer energy (to eachother)
Your calculations look right to me. You need a germanium diode, not a silicon diode, not a Schotkky diode. That's because it needs to be leaky. I use 1N34 but there are plenty of equivalent part numbers. Be sure to also watch the links to my other crystal radio videos related to this circuit in the description below this video. There's a lot of helpful information in them.
And thanks! Blender rocks! You now know why I appreciate your channel. :)
You have explained the concept of radio to the best detail, you are a very good teacher.
Keep up the good work RimstarOrg
I agree with the compliments (excellent presentation) and the main criticism (a little too fast) of this video.
To be fair, being on TH-cam, you can always replay it!
In addition, you can go to settings and lower the playback speed. ;-)
Great video RimstarOrg. Veeeeeeeeery Greaaaaaaaaaat
Best explanation; broad, concise introduction. Thanks :)
Wow. Coming from someone with your background that means a lot. Thanks! I deliberately try to leave as little as possible to the imagination, so it sounds like it's working. I hope you enjoy the rest of my videos as much. Welcome!
I'm using blender, which is a very powerful 3D modelling and animation software available at blender.org. Warning, it takes a lot of learning.
Maybe *you* could be the one to teach us Blender! Great video and explanation.
explained in a "crystal clear" way. *walks away*
LOL
You're welcome. And thanks for letting me know it helped. Success!
This is the most easy to understand instruction type video i have EVER seen on TH-cam. You explain and show it so well. Fantastic stuff & thanks a million for uploading this. I have no idea why you have so little views.
My brain hurts!!!... My ears are still trying to catch up, but to be fair, it made sense and I actually get how the transmission part from a radio station actually works... So yeah, thanks for a concise presentation...
When my ears hurt, trying to keep up, I change the speed to 75 %. HTH. You're welcome.
The guy sounds like Badger from the Breaking Bad!
pleasant memories. I built my first crystal radio at age 8. Then I modified it to receive shortwave frequencies. Next step was a 2 transistor radio, powered by a single D cell battery. Been in electronics ever since. Thank you, sir for the video. Well done.
Wonderful! This is perhaps the best explanation of the basics of radio I have found! As a physics major in school I learned about LC circuits and how Maxwell's equations allow for radio waves, but not how it worked to make a radio. I just got my amateur radio license (yes, 40 years too late), and you learn all the parts and rules of thumb, but not how it relates to the physics. Your explanation is the perfect middle ground and brings it all together. Thank you so much!
Turns on the radio, it's playing "one direction" turns radio off.
img.memecdn.com/best-fucking-direction-ever_o_1863437.jpg
This is 90% there, but I feel you are cheating by using a fancy-smancy store-bought diode. I want to know how to polish and mount a piece of galena to make a crystal diode radio set as used in days of yore. Or, how about a razor-blade radio?
I recall, years ago I opened up a radio to try to find the pile of soil (earth) listed on the circuit diagram. To this day I find the use of the word "earth" or even "ground" to be very irksome.
baddoggie101 I would like to try the galena and cat's whisker some day, just haven't gotten around to it yet (too many projects.) I've done the razor-blade diode in this video "Make Razor Blade Diode for Crystal Radio/Foxhole Radio".Regarding looking for the earth in the radio, :). Sounds like something I would do too.
RimstarOrg Taking another look at your very fine animation I see something else that is a little bit screwy. I appears as if you have five conductors coming together into a single node which is connected to ground. I think your sketch is "sketchy" in that you probably did not mean to imply that they are all connected at that node. Only the leg of the primary coil should be connected to ground. In addition, if the diode was reversed and the right most conductor was connected only to ground it should also work, provided you use one of those early type of earphones that drove the earpiece diaphragm with a coil. Correct me if I am wrong.
baddoggie101
You had me worried for a second. All 5 are all connected to ground at the common node. You can even see it in my actual crystal radio which was the model for this 3D animation th-cam.com/video/VqdcU9ULAlA/w-d-xo.html
Thanks! And you're welcome! It certainly is one of the ones I'm most proud of.
You're welcome! And thanks for the great feedback. That was my goal so, success.
slooooooowwwwwwwwwwww dddddddooooooooooooowwwwwwnnnnnnnn.... omg, so much so fast. Overwhelming to the complete novice. But otherwise excellent.
+Mark V slooooooowwwwwwwwwwww dddddddooooooooooooowwwwwwnnnnnnnn.... omg, so much so fast.
+Mark V I had to pause it many times. It is great
You can reduce the playback speed of a TH-cam video.
Such a shame, you're speaking WAAAY too fast for an educational video. For rapid-fire jokes in a comedy club this style is perfect, but here you're trying to explain a scientific principle to those who may not have encountered this subject before, or who don't have English as a first language, and you've raced through the script, removing most of the gaps and even all the breaths!! I say it's a shame because your graphics are really nice. I found myself having to go back repeatedly to try and get the gist of what you were saying, which made it a less-than-pleasurable learning experience. If you're teaching, slow down man! We're not all up to your speed yet.
To be fair such a subjects have to be watched back again and pondered about, you can't get everything the first time
he spoke so fast it " Hertz " XD
in the settings button in the player you can change the speed of the video.
no kidding :)
Put it on 0.75...
Thanks, fantastic presentation! Love when you bring it down to the electron level. Subscribed
The animations are absolutely good and your descriptions are clear. Thank you very much the excellent job.
What a wonderful and complete description indeed. Thank you so very much. ⭐️
Probably the best explanation of radio wave reception via crystal radios that I have ever seen.
Your graphics are outstanding and easy to understand. Thanks for all the effort you put into your videos.
Crean en Jesús Cristo y tendrán vida eterna y paz entreguénce a Jesús Cristo ahora mismo en oración Dios les bendiga
Les invito a una iglesia evangélica
very useful indeed... I have used to read about radio since I was 12 years old... but this one clarify many details related to antenna that I could not understand until I saw this video...really very useful...
Great work and great effort
Best explanation for crystal radio I ever saw. Thanks a lot!
A truly great video. Excellent explanation. I love ow you explained everything that is specific to to the main objective and left it to us to find out the details :).
Nothing new to say, best explanation anyone could ask for.
Many thanks!
You have done it! Finally, a clear well presented video on the crystal radio,
I hope it inspires inquisitive minds while AM is still broadcasting!
You're welcome, and thank you. I'm glad you like it.
Excellent video it renewed an interest in me that had been undisturbed for.sometime, thank you.
Thanks! Glad you like it!
Excellent video. This seems as a more complicated radio set. As a kid I made a radio out of a purchased crystal. I used a razor blade, coil, crystal, and a small earbud. It worked very good.
Fantastic! I like how you have thought up all the most likely questions and explained them. You should write a book for electronics hobbyists!
You're welcome. Thanks for letting me know that it helps.