I used to manufacture breakover diodes in a power semiconductor plant. Videos like this are great for new kids coming through to get an appreciation for the science behind semiconductors. Great work Jeri!
Thank you. With your drawing i finally understand how diodes and transistors works ! If some teachers could take example on your explanation it would have helped a lot when i was younger :)
Well this was uploaded a long time ago. I am now thinking about trying to make a transistor and was doing a little searching to see who did what prior. Such a good piece of work here. Thanks for sharing. Think I will subscribe too.
Any gamma (photon) or beta (free electron) radiation which interacts in the depletion region of a PN junction will produce one or more electron-hole-pairs (excitons). The built-in voltage of the junction will cause the electron to drift towards the P side and the hole towards the N side. This is how a basic photodiode or solar cell works. You only need several million or billion gamma/beta rays per second to generate anything in the range of a few volts.
@trailkeeper Only the wrap on the strings are phosphor-bronze. The core is steel. Piano Strings also use this construction technique. Some actually are bronze wrapped nylon wrapping steel.
Thanks for another great, educational video! -- Heat seems to break the glass envelope rather easily as well, but I'm not sure if the properties of the die are changed permanently or not!
@jeriellsworth I was stunned. How neat! I mean, you just don't think of it being possible. And that parallels your experimentation on things, or visa versa. Why, tis fun to see and consider. It is.
that was clearer then the explanation I got in cegep ! you mention you got some information from patents can you tell how you browsed/searched and viewed the patents ? there are a bunch of patent search engines online but the ones I tried the search was terrible and the patents were incomplete :( (figures mentionned in the document were missing for example) also using a pizeo headphone like you said in your standford talk, that's a great trick, especially for those who don't have scopes :)
@AmazGraz The gain would be theoretically linear in an ideal device, if there were such a thing. In reality, there's a range on one side where it doesn't conduct a signal at all, a range on the other side where it's wide open (and so burns up if you're not careful), and a range in the middle where it's fairly linear. That middle is what you use in (analog) amplifiers. In digital circuits you just use the all-the-way-off and all-the-way-on ends.
You might want to try phosphor-bronze guitar strings for your collector formation. The high "E" string is nice and thin and you will get plenty of wire out of one string.
@AmazGraz I was into electronics when I was in high school, but I was, ever so regrettably, weak in math, and sad to say, discipline. But it still ever fascinates me.
This afternoon I found a link that could be helpful for making a ß cell. Gallium nitride is used for these batteries because it has the widest band gap, 3.4eV, out of all the common semiconductors (there are some other reasons why it's chosen over silicon carbide and gallium arsenide). If you want I can send you the link, it's a power point from a university in Iran. It's not a very high content source of information but it's the only one about ß cell semiconductors I've found thus far.
Thanks for the info. The challenges seem to be in the construction rather than the theory. Theory will tell you which semiconductors to use, IIRC silicon carbide is the semiconductor of choice (cheap and rugged but not very efficient). The theory is deceivingly simple. In practice, layers of ultra-pure semiconducting material have to be deposited in uniform layers, merely nanometers thick. Tritium effuses very fast through everything and is extremely expensive (more expensive than gold).
Wow this was interesting! I do know the early years of transistor development had problems with pitting during diffusion on the semiconductor - it was a lot worse with Silicon though than Germanium as the melt temperature was a lot higher with silicon. With Silicon at least it was solvable with silicon dioxide (Frosch in early 1955).
did you see "Fran lab's" video from this year, a 40 minute black and white documentary on how they developed the transistor back than? also discusses the masking technique, math, etc, etc.
@jeriellsworth Well when you put it that way..... But mind you, I am but a rank amateur as an electronics buff. And since I have your attention, I have been wondering, as we know analog receiving circuits work by narrowing down the bandwidth to select the input we want to tune into and amplify. Does digital work this way, or does it bypass the capacitance/inductance tuning circuit?
...ctd... You'll also hear of PiN diodes, which have a layer of intrinsic semiconductor between the P and N region. Intrinsic just means there are no excess holes or electrons. Since the radiation must interact with the semiconductor lattice to produce an electron-hole-pair, and it must be in the depletion region for each to drift to its respective metal contact, the larger intrinsic (depletion) region allows for a better chance for this to happen as much as possible, producing more cell voltage
@onlygearwarrior Oh, i loved my science teachers too, but when coming to explaining PN junction it was like "when you're applying voltage they let pass current". They never explained why and how. That's why i couldn't understand and remember how they work (yes can't remember something i don't really understand)
Anyway I read in my fathers very old Dutch books and magazines, that the real first experimental transistor was build, using a natural crystal, where wires where burnt in using high voltage and by burning them into the crystal, not only was the wire welded to it, but also by using the right kind of metal two either P or N regions where created with the cristal itself being the opposite of those two regions either P or N. Can't remember if the burned in wire caused a P or N region. This was first discovered as a means to make an advanced version of the cats-whiskers diode by burning in one wire preventing one had to feel around with the whisker. Someone for some reason decided to burn in two wires and started using measuring equipment and Voila the discovery of the transistor. This diode was called a contact diode to distinguish it from its predecessor the point contact diode aka cats-whisker diode. Some of these technical magazines of my father are stolen but if I can find the one describing it I might try building a prehistoric diode and transistor. Important in this is the use of a natural crystal since it is already slightly P or N by itself from natural occurring impurities. If I could only remember the right P or N it is not either P or N AFAIK it is always the same one of the two by nature. AFAIK this is how the transistor is really discovered, although there might be different story's. Sorry for the history lesson. Ps forgive me for any language mistakes since English is not my native speech Dutch is. Bedankt = thank you.
Hello Jeri! Did you stop recording your videos and doing experiments? Is it possible to ask some a little bit personal questions about the aim of these experiments, why did you do them? Thank you.
I love you Jeri. Can you say what is going to be the NEXT THING in electronics. Memories? Capacitor that can hold charge for many years (to be used as memory) ?
I recently stumbled upon some internet pages on tritium batteries; batteries that convert the kinetic energy of high energy ß rays emmited by ß emmitors (eg. tritium and zinc-70) into an electrical current. Now, these pages don't go into detail about what semiconductors are used to convert ß rays into an electrical current. Do you have any idea as to what kind of semiconductor might be used for this purpose? Every electronics and nuclear physics nerd I have asked so far had no clue.
@AmazGraz You're not getting something for nothing; it takes added power to get that bigger signal, which is why you have the battery/power supply hooked up to the collector. And of course you waste some of that power along the way; the Second Law always finds you, even if you're hiding in a transistor :)
@jeriellsworth I was wondering if you could use a solar cell. The band gap of the solar cell and the energies of the beta rays are probably not compatible and thus the efficiency of the cell would be quite low.
Thanks Geri.... I FINALLY "get" how dopants and P-type or N-type work... If they'd just told us it was about covalent bonds when I was at school I would have "got" free electrons and holes from the get-go.
Uhm, Hi Jeri. I just wanted to tell you that you should have a tv show on Discovery Channel, teaching things like this and the physics and chemistry involved, some like Mythbusters or How Stuff Works and including some good cgi animations. I'd love a show like that. Btw, time ago, i was trying (inspired by you ^_^) to change icons in my old mp3 player, by access the BIOS. Was a complete fail u.u but i know if you teach how, i'll learn. Nice video though
Point contact transistors are odd things in their own right, the Alpha is higher than the Beta, so they have to be run in common base mode. This is the opposite to BJT's. I wonder if Jeri can explain why this is :)
Is there a way to make a larger, higher power version? You would likely need to have a larger surface area of doped material but with a transistor of appreciable size one can make hardier devices - if last gen tech.
You would also need fairly high voltage to replace the cat's whisker. Tesla used a spark gap for this purpose, but his was two way. With an inductor one terminal and a cap of the other you can make them one way.
No doubt an Electric Discharge Machining device will be the best way to sharpen something to a point. I once read how that hypodermic needles were made ouchless by the EDM process once upon a time. Yea, I remember when they used to hurt when they put them in. But by EDM the burrs were removed. 6^)
@alphabeets Luckily no. When you remove electrons from a most materials the attraction is so strong it will pick them up from things that come in contact. I should show the crazy electrophorus effect someday, where you can remove or add electrons to metal and then leave the metal in this state for a very long time. (or shock someone with it. :))
Try en.wikipedia.org/wiki/Phase-shift_oscillator which one suspects is what Jeri used. But remember that 𝛽 will be quite low. It's a good idea to practice with a modern transistor first, something such as learningaboutelectronics.com/Articles/Sine-wave-generator-circuit-with-a-transistor.php might be fun & useful.
Why do they call them amplifiers? Technically they are not. Like one teacher said, "You don't get something from nothing." I think, technically, that they should be called gates. But they gave that name to another device. There may be a better name, a more descriptive name which relates to the fact that they 'gain' (or the associated circuit gains) relative to the bias applied. But that is not right either. Now is gain proportional, linear relative to the bias or simply predetermined by....?
You might want to remind kids or anyone to use safety goggles or eye protection for this one, as well as washing their hands after sanding the glass or material that gets on their hands!
True it is BUT I have a copy of a paper that Bardeen wrote that explains in full about a 3 point contact transistor. In that paper it states that Bell Labs tried different contacts. It states that the best contact was in fact a Phosphorus Bronze contact on an N-type piece of Germanium. The only thing wrong with Geri's experiment was on her collector forming. The paper states that it should be REVERSE biased and NOT Forward biased as she did in her experiment.
I appreciate your efforts, but after growing up with transistors, I find it exceedingly difficult to talk myself into going back to the early days and build a point contact transistor, especially when I can buy a hundred of the best silicon transistors for a few dollars. You showed the original point contact as being built on a slab of PN material. In the books I've read, I've never seen that, and I thought that the original was a solid block of a single material. Tell me I'm wrong, please.
...so, theoretically can a transistor be "used up"? Do the electrons leave it and get depleted like emptying the gas tank in a car? Perhaps the "depletion" would take a really long time becuase there are so many of them? Just curious. Jeri rules!
I used to manufacture breakover diodes in a power semiconductor plant. Videos like this are great for new kids coming through to get an appreciation for the science behind semiconductors. Great work Jeri!
Indeed this is something that should be learned at school. At least at technical education directions. Certainly at MIT !!!
MIT students probably have already done that at home even before setting foot in MIT.
This was really good! Thank you so much for sharing this. This is the first time I see somebody making a transistor using a diode. Thanks!
very very cool
I got all excited when I heard the oscillator!
I can't wait to try this myself.
That was a nice dedication at the end there too
:)
This video is OVER THE TOP in greatness! I have some 2N23s here, which are early Ge point-contact transistors.
Thank you! I needed this for an experiment and couldn’t find a good vid!
Thank you. With your drawing i finally understand how diodes and transistors works ! If some teachers could take example on your explanation it would have helped a lot when i was younger :)
Amazing video, even 12 years later ^-^
Well this was uploaded a long time ago. I am now thinking about trying to make a transistor and was doing a little searching to see who did what prior. Such a good piece of work here. Thanks for sharing. Think I will subscribe too.
Any gamma (photon) or beta (free electron) radiation which interacts in the depletion region of a PN junction will produce one or more electron-hole-pairs (excitons). The built-in voltage of the junction will cause the electron to drift towards the P side and the hole towards the N side. This is how a basic photodiode or solar cell works. You only need several million or billion gamma/beta rays per second to generate anything in the range of a few volts.
Fascinating video. Thanks for putting it up.
I remember that day that I figured out how to switch a BJT on and off. I killed a couple of them, but was very pleased in the end
Man, I wish i had you as a professor when I took (and failed) my EE classes back in college.
Do it yourself transistor at home. Awesome! I love these videos...keep it up!
@trailkeeper Only the wrap on the strings are phosphor-bronze. The core is steel. Piano Strings also use this construction technique. Some actually are bronze wrapped nylon wrapping steel.
That is FREAKIN' AWESOME !!!
So cool! Thanks for helping us learn.
I love your videos, Jeri. You talk nerd like no other : )
So awesome! *puts in favorites*
Thanks for another great, educational video! -- Heat seems to break the glass envelope rather easily as well, but I'm not sure if the properties of the die are changed permanently or not!
@jeriellsworth I was stunned. How neat! I mean, you just don't think of it being possible. And that parallels your experimentation on things, or visa versa. Why, tis fun to see and consider. It is.
that was clearer then the explanation I got in cegep !
you mention you got some information from patents
can you tell how you browsed/searched and viewed the patents ?
there are a bunch of patent search engines online but the ones I tried the search was terrible and the patents were incomplete :( (figures mentionned in the document were missing for example)
also using a pizeo headphone like you said in your standford talk, that's a great trick, especially for those who don't have scopes :)
They make phosphorus bronze acoustic guitar strings if you are interested in using something more like a pin.
@AmazGraz The gain would be theoretically linear in an ideal device, if there were such a thing.
In reality, there's a range on one side where it doesn't conduct a signal at all, a range on the other side where it's wide open (and so burns up if you're not careful), and a range in the middle where it's fairly linear.
That middle is what you use in (analog) amplifiers. In digital circuits you just use the all-the-way-off and all-the-way-on ends.
Brilliant!
You might want to try phosphor-bronze guitar strings for your collector formation. The high "E" string is nice and thin and you will get plenty of wire out of one string.
the high E is steel in most brands, the bronze alloy is wrapping the low strings
@AmazGraz I was into electronics when I was in high school, but I was, ever so regrettably, weak in math, and sad to say, discipline. But it still ever fascinates me.
Fantastic.
@jeriellsworth is it possible that the circuit is acting like a relaxation oscillator and the germanium is like a zener diode or like a spark gap?
This afternoon I found a link that could be helpful for making a ß cell. Gallium nitride is used for these batteries because it has the widest band gap, 3.4eV, out of all the common semiconductors (there are some other reasons why it's chosen over silicon carbide and gallium arsenide).
If you want I can send you the link, it's a power point from a university in Iran. It's not a very high content source of information but it's the only one about ß cell semiconductors I've found thus far.
Thanks for the info. The challenges seem to be in the construction rather than the theory. Theory will tell you which semiconductors to use, IIRC silicon carbide is the semiconductor of choice (cheap and rugged but not very efficient).
The theory is deceivingly simple. In practice, layers of ultra-pure semiconducting material have to be deposited in uniform layers, merely nanometers thick. Tritium effuses very fast through everything and is extremely expensive (more expensive than gold).
Wow this was interesting! I do know the early years of transistor development had problems with pitting during diffusion on the semiconductor - it was a lot worse with Silicon though than Germanium as the melt temperature was a lot higher with silicon. With Silicon at least it was solvable with silicon dioxide (Frosch in early 1955).
did you see "Fran lab's" video from this year, a 40 minute black and white documentary on how they developed the transistor back than?
also discusses the masking technique, math, etc, etc.
@jeriellsworth Well when you put it that way..... But mind you, I am but a rank amateur as an electronics buff. And since I have your attention, I have been wondering, as we know analog receiving circuits work by narrowing down the bandwidth to select the input we want to tune into and amplify. Does digital work this way, or does it bypass the capacitance/inductance tuning circuit?
Me encanta su atrevimiento, un transistor en casa, buena esa.
@jeriellsworth You're so devious!! :) Thanks for responding. I agree with others, you should have your own show maybe on the Discovery Network.
...ctd...
You'll also hear of PiN diodes, which have a layer of intrinsic semiconductor between the P and N region. Intrinsic just means there are no excess holes or electrons. Since the radiation must interact with the semiconductor lattice to produce an electron-hole-pair, and it must be in the depletion region for each to drift to its respective metal contact, the larger intrinsic (depletion) region allows for a better chance for this to happen as much as possible, producing more cell voltage
@onlygearwarrior Oh, i loved my science teachers too, but when coming to explaining PN junction it was like "when you're applying voltage they let pass current". They never explained why and how. That's why i couldn't understand and remember how they work (yes can't remember something i don't really understand)
@AmazGraz By the way, your 1N34 video is awesome too.
AmazGraz, it is call amplifier because in diferent configuration you can control a big current out with and small current in
Anyway I read in my fathers very old Dutch books and magazines, that the real first experimental transistor was build, using a natural crystal, where wires where burnt in using high voltage and by burning them into the crystal, not only was the wire welded to it, but also by using the right kind of metal two either P or N regions where created with the cristal itself being the opposite of those two regions either P or N. Can't remember if the burned in wire caused a P or N region. This was first discovered as a means to make an advanced version of the cats-whiskers diode by burning in one wire preventing one had to feel around with the whisker. Someone for some reason decided to burn in two wires and started using measuring equipment and Voila the discovery of the transistor. This diode was called a contact diode to distinguish it from its predecessor the point contact diode aka cats-whisker diode. Some of these technical magazines of my father are stolen but if I can find the one describing it I might try building a prehistoric diode and transistor. Important in this is the use of a natural crystal since it is already slightly P or N by itself from natural occurring impurities. If I could only remember the right P or N it is not either P or N AFAIK it is always the same one of the two by nature. AFAIK this is how the transistor is really discovered, although there might be different story's. Sorry for the history lesson. Ps forgive me for any language mistakes since English is not my native speech Dutch is. Bedankt = thank you.
Welke Magazin was het van jouw vader? Mischien heb ik hem RB of Elektuur?of…….
Can you give some references about your fathers journals and books? Very interesting topic.
Jerri, I
i just love you
was that the AMRAY for the microscope shots?
@AmazGraz Yes. Hollow space goodness. That guy does a marvelous job of making them too.
Hello Jeri!
Did you stop recording your videos and doing experiments? Is it possible to ask some a little bit personal questions about the aim of these experiments, why did you do them?
Thank you.
great job
I want to make a small sputtering magnetron and use foil stencils or something, to make a bipolar transistor
U r awesome!!
I love you Jeri. Can you say what is going to be the NEXT THING in electronics. Memories? Capacitor that can hold charge for many years (to be used as memory) ?
I recently stumbled upon some internet pages on tritium batteries; batteries that convert the kinetic energy of high energy ß rays emmited by ß emmitors (eg. tritium and zinc-70) into an electrical current. Now, these pages don't go into detail about what semiconductors are used to convert ß rays into an electrical current. Do you have any idea as to what kind of semiconductor might be used for this purpose? Every electronics and nuclear physics nerd I have asked so far had no clue.
@AmazGraz You're not getting something for nothing; it takes added power to get that bigger signal, which is why you have the battery/power supply hooked up to the collector.
And of course you waste some of that power along the way; the Second Law always finds you, even if you're hiding in a transistor :)
@yellowmetalcyborg I don't know for sure. I've always wanted to make a nuclear battery.
Jeri is the best woman in the youtube, +1.
Cool!
@jeriellsworth I was wondering if you could use a solar cell. The band gap of the solar cell and the energies of the beta rays are probably not compatible and thus the efficiency of the cell would be quite low.
You reminded me of George cove and his lowtech photovoltaic panel
@AmazGraz Amplification doesn't seem too bad to me. Forming a larger copy of the input, doesn't imply there wont be losses.
Thanks Geri.... I FINALLY "get" how dopants and P-type or N-type work... If they'd just told us it was about covalent bonds when I was at school I would have "got" free electrons and holes from the get-go.
@AmazGraz Of course they are!
an output signal is greater in amplitude than the input signal
."something from nothing. " is not relevant or implied.
That made so much more sense o.o
I think some acoustic guitar and maby some piano strings are phosphor-bronze metal.
Uhm, Hi Jeri. I just wanted to tell you that you should have a tv show on Discovery Channel, teaching things like this and the physics and chemistry involved, some like Mythbusters or How Stuff Works and including some good cgi animations. I'd love a show like that. Btw, time ago, i was trying (inspired by you ^_^) to change icons in my old mp3 player, by access the BIOS. Was a complete fail u.u but i know if you teach how, i'll learn.
Nice video though
@AmazGraz Video 1 is voodoo. It is sorcery. I feel like making the sign of the Cross, and.... and..... Wow. I'm stunned.
Wow. Very impressive. That must of been tedious :)
Point contact transistors are odd things in their own right, the Alpha is higher than the Beta, so they have to be run in common base mode. This is the opposite to BJT's. I wonder if Jeri can explain why this is :)
Is there a way to make a larger, higher power version? You would likely need to have a larger surface area of doped material but with a transistor of appreciable size one can make hardier devices - if last gen tech.
You would also need fairly high voltage to replace the cat's whisker. Tesla used a spark gap for this purpose, but his was two way. With an inductor one terminal and a cap of the other you can make them one way.
very good like this and like you
No doubt an Electric Discharge Machining device will be the best way to sharpen something to a point. I once read how that hypodermic needles were made ouchless by the EDM process once upon a time. Yea, I remember when they used to hurt when they put them in. But by EDM the burrs were removed. 6^)
@alphabeets Luckily no. When you remove electrons from a most materials the attraction is so strong it will pick them up from things that come in contact. I should show the crazy electrophorus effect someday, where you can remove or add electrons to metal and then leave the metal in this state for a very long time. (or shock someone with it. :))
cool
I understood everything but the holes. Could you give a detailed definition of said 🕳
@jeriellsworth Lucily no! LOL. Good answer.
@trailkeeper piano wire might be easier to sharpen.
Hello how to wire a point transistor in a circuit? I'm looking for a schematic
Try en.wikipedia.org/wiki/Phase-shift_oscillator which one suspects is what Jeri used. But remember that 𝛽 will be quite low. It's a good idea to practice with a modern transistor first, something such as learningaboutelectronics.com/Articles/Sine-wave-generator-circuit-with-a-transistor.php might be fun & useful.
@thewii552. It was optical.
Why do they call them amplifiers? Technically they are not. Like one teacher said, "You don't get something from nothing." I think, technically, that they should be called gates. But they gave that name to another device. There may be a better name, a more descriptive name which relates to the fact that they 'gain' (or the associated circuit gains) relative to the bias applied. But that is not right either. Now is gain proportional, linear relative to the bias or simply predetermined by....?
You might want to remind kids or anyone to use safety goggles or eye protection for this one, as well as washing their hands after sanding the glass or material that gets on their hands!
Can anyone please point me in the right direction of a schematic of an oscillator using only one PNP transistor.
@RSole52 Thas so funny 8^)
you are so fucking cool
Phosphorus is an N type dopant though.
True it is BUT I have a copy of a paper that Bardeen wrote that explains in full about a 3 point contact transistor. In that paper it states that Bell Labs tried different contacts. It states that the best contact was in fact a Phosphorus Bronze contact on an N-type piece of Germanium.
The only thing wrong with Geri's experiment was on her collector forming. The paper states that it should be REVERSE biased and NOT Forward biased as she did in her experiment.
FET would be easier no
Hey,just a little correction.There is no such a word like Acceptor....Its Recipient....Thank you!a wonderful video!
AFAIK, acceptor's commonly used in electronics, while recipient's used in medicine
any video that starts " so a bunch of nerds..." gets a like from me
I appreciate your efforts, but after growing up with transistors, I find it exceedingly difficult to talk myself into going back to the early days and build a point contact transistor, especially when I can buy a hundred of the best silicon transistors for a few dollars. You showed the original point contact as being built on a slab of PN material. In the books I've read, I've never seen that, and I thought that the original was a solid block of a single material. Tell me I'm wrong, please.
...so, theoretically can a transistor be "used up"? Do the electrons leave it and get depleted like emptying the gas tank in a car? Perhaps the "depletion" would take a really long time becuase there are so many of them? Just curious. Jeri rules!
The first 5 seconds sound nearly made me close this video
I am curious to know who are those 5 who disliked the video.
Yashas closed minded people. They already know everything lol
Me, she destroyed a worthy germanium diode to make this, also she didn't show if it works or not... that sound at the end doesn't means nothing to me
Likely they have billions of transistors in their phone and don't see what difference one more will make...
@@giacomobaldon1450 The "sound at the end" means that the transistor has demonstrated power gain, and is thus, in principle, useful!
the anti semiconductor comittee
THAT'S WHY THE F****** DIODE SYMBOL LOOKS LIKE THAT??
@yellowmetalcyborg I'd love to see it. You can send a pointer to scorched.chips at gmail.com