I absolutely loved your show David.. IT was always a special treat when i was able to catch it in the states. Also a huge fan of Tim Hunkin's "secret life of machines" you guys fueled my geek mindset!
Already knowing quite a bit about electricity and it's relationship with magnetism helped me understand what he was talking about but I'm afraid a person not knowing those key things wouldn't know what he's talking about in this video. I noticed a lot of places a person would have to overwhelmingly ask "but why" and get lost and bored where I just already knew the answer and kept listening.
3:33 How do the capacitor and coil work to tune the radio? Is a "resonance circuit" one that matches the wavelength of the carrier wave? Doesn't the capacitor simply store charge? I'm a bit confused
Honestly, this would take a lot of math, physics, and circuit theory to explain in detail. I will make my best attempt to explain it to you here. The coil of wire (an inductor) will produce a magnetic field when it is exposed to a current. When that current drops, the magnetic field, which will take some time (as the presenter explained). The energy of the magnetic field will be converted back into some electric current which flow out of the inductor, into the capacitor. As this capacitor receives current, it will store energy in an electric field. Since the capacitor is connected up to the inductor (which is just a coiled conductor), the charge has a path to escape after this field builds up. As the current escapes, the current will go back into the inductor. The changing current will again induce a magnetic field. And so it goes, back and forth. What we've described here is basically and electrical spring. The capacitor will resist a constant current. The inductor will resist a changing current. So at a higher frequency, the capacitor will reject low frequencies (closer to constant), while the inductor will let them pass. At high frequencies (changing faster), the capacitor will allow the signal to pass, while the inductor will block it. If you connect these in a closed loop, you will create a situation where only certain range of frequencies will pass, depending on the type of capacitors and inductors used. Hopefully that gave you some idea of how it works. If you have any questions, I'll try to answer them.
@Iseekoutthetruth thats effectively what its doing, your listening to the change in voltage (sound). Its electro magnetic induction and how electrical generation works. The energy you can harness from radio is not useful for much else as its too small. Michael Farady moved a magnet through a coil to produce energy. This is whats happening but the magnet in this case is the radio signal.
i have already made a crystal radio..i just want to add a transistor in it...i dont know where to put it in curcuit..can you help me...i have npn 2n3904...i just want to amplify for a small speaker..later i will attach it to computer speakers for more amplification..i just need a small amplification now
@hydrohobbyist isn't that how Tesla did it for his Electric car using a radio signal and a super capacitor to keep his battery's charged as he drove it?
Well, then when we speak about the discovery of the photoelectric effect we should mention Newton because he is one of the fathers of Physics. Such logic is flawed.
The only thing better than Acmeschool is being in a lab getting hands on experience with a proffesor explaining everything to you. Great videos!
A truly EXCELLENT presentation. This really does concentrate on what is important !!
I absolutely loved your show David.. IT was always a special treat when i was able to catch it in the states. Also a huge fan of Tim Hunkin's "secret life of machines" you guys fueled my geek mindset!
really this is a world of physics where simplicity means elegance!!!
Already knowing quite a bit about electricity and it's relationship with magnetism helped me understand what he was talking about but I'm afraid a person not knowing those key things wouldn't know what he's talking about in this video. I noticed a lot of places a person would have to overwhelmingly ask "but why" and get lost and bored where I just already knew the answer and kept listening.
MAN_ON_WHEELZ any suggestions for a video that explains the fundamentals
could you use a Am radio as a generator? by receiving frequency's and converting them to volts?
3:33 How do the capacitor and coil work to tune the radio? Is a "resonance circuit" one that matches the wavelength of the carrier wave? Doesn't the capacitor simply store charge? I'm a bit confused
Honestly, this would take a lot of math, physics, and circuit theory to explain in detail. I will make my best attempt to explain it to you here. The coil of wire (an inductor) will produce a magnetic field when it is exposed to a current. When that current drops, the magnetic field, which will take some time (as the presenter explained). The energy of the magnetic field will be converted back into some electric current which flow out of the inductor, into the capacitor. As this capacitor receives current, it will store energy in an electric field. Since the capacitor is connected up to the inductor (which is just a coiled conductor), the charge has a path to escape after this field builds up. As the current escapes, the current will go back into the inductor. The changing current will again induce a magnetic field. And so it goes, back and forth. What we've described here is basically and electrical spring.
The capacitor will resist a constant current. The inductor will resist a changing current. So at a higher frequency, the capacitor will reject low frequencies (closer to constant), while the inductor will let them pass. At high frequencies (changing faster), the capacitor will allow the signal to pass, while the inductor will block it. If you connect these in a closed loop, you will create a situation where only certain range of frequencies will pass, depending on the type of capacitors and inductors used.
Hopefully that gave you some idea of how it works. If you have any questions, I'll try to answer them.
He speaks perfectly clearly and he isn't too fast. Is English your first language? If not I understand you lack of understanding.
@Iseekoutthetruth thats effectively what its doing, your listening to the change in voltage (sound). Its electro magnetic induction and how electrical generation works. The energy you can harness from radio is not useful for much else as its too small. Michael Farady moved a magnet through a coil to produce energy. This is whats happening but the magnet in this case is the radio signal.
i have already made a crystal radio..i just want to add a transistor in it...i dont know where to put it in curcuit..can you help me...i have npn 2n3904...i just want to amplify for a small speaker..later i will attach it to computer speakers for more amplification..i just need a small amplification now
@hydrohobbyist isn't that how Tesla did it for his Electric car using a radio signal and a super capacitor to keep his battery's charged as he drove it?
"Don't blame science." A meme waiting to happen.
Fantastic work
Could I use this in a presentation for school?...
Wow. I have not seen this show in years.
He mentioned Reginald Fessenden though, the first man to transmit voice by radio.
@Iseekoutthetruth No that was a flux capacitor, but they havent been invented yet.
It's the guy fro Fast Forward hurray!
Brilliant.
Well done, tyty!
What about tesla?
@hydrohobbyist lol yea or did they? maybe Tesla was from the future????
In what way is he the father of radio?
because of his fundamental contributions to wireless energy transfer?
Oh man he had to go and throw music theory in there.
But he mentioned Maxwell, Hertz and Marconi. He should have the decency to mention Tesla.
Remember, "Don't blame science."
why not also mention Nikola Tesla name ? -.-'
cool
why'd he leave out nikola tesla?
Because Tesla has always been over rated and had nothing to do with radio. Go smoke another joint.
I wish those targeted would sound more coherent and intelligent. Makes genuine targets look stupid.
Radio waves don't "collapse". They fly away. Outwards, not inwards back again.
You don't need to mention Tesla if you want to explain how a radio works...
Dangerous to create short circuits like that.
On a 1.5 volt cell? Really, is that the best you can do?
Well, then when we speak about the discovery of the photoelectric effect we should mention Newton because he is one of the fathers of Physics. Such logic is flawed.
@DeductiveReason wrap your house in tinfoil
Hehehehehe. Exactly, why it is necessary to mention the "father of radio", if you want to explain how radio works
I feel stupid listening to what he said.. and yet he said this is a loser explanation..
Just because he is famous?
better if he spoke slower and more clearly.
yawn!