[User] Please transcribe this text

[Assistant] At its most basic, a stair is a way to get from point A to point B at different elevations. Stairs have a common language. Treads, which is the thing that you walk on.


[User] Please transcribe this text

[Assistant] Riser, which is the vertical element that separates the two treads. A lot of stairs have nosings that create a kind of edge. And then the connected piece is a stringer.


[User] Please transcribe this text

[Assistant] I assume stairs came to be from the first time someone said, I want to get to this higher rock from the lower rock. People climbed using whatever was available. Stepped logs, ladders, and natural pathways that were worn over time.


[User] Please transcribe this text

[Assistant] Some of the earliest staircases, like the pyramids in Chichen Itza, or the roads to Mount Tai in China, were a means of getting to a higher elevation when people sought for worship or for protection.


[User] Please transcribe this text

[Assistant] As engineering has evolved, so has what's practical. Stairs can be made from all kinds of material. There are linear stairs, there are spiraled stairs. Stairs can be indoors, they can be outdoors. They clearly help us in an emergency, but they are also a form of art in and of themselves.


[User] Please transcribe this text

[Assistant] As we move across the stairway, the form dictates our pacing, our feeling, our safety, and our relationship and engagement with the space around us.


[User] Please transcribe this text

[Assistant] So for a second, think about stepping down a gradual, monumental staircase, like the one in front of the New York Public Library.


[User] Please transcribe this text

[Assistant] From those steps, you have a view of the street and all the people around you and your walk is slow and steady because the tread is so wide. That's a totally different experience than going down the narrow staircase to say an old pub where you spill into the room. There you encounter tall risers so you move more quickly.


[User] Please transcribe this text

[Assistant] Stairs add enormous drama. Think about how stairs signal a grand entrance and we're the star of that moment. Stairs can even be heroic.


[User] Please transcribe this text

[Assistant] The staircase that remained standing after September 11th and the attack on the World Trade Center.


[User] Please transcribe this text

[Assistant] was dubbed the Survivor Staircase because it played such a central role in leading hundreds of people to safety.


[User] Please transcribe this text

[Assistant] But small stairs can have a huge impact too. The stoop is a place that invites neighbors to gather, blast music, and watch the city in motion.


[User] Please transcribe this text

[Assistant] Fascinating to me that you see people wanting to hang out on the stairs. I think they feel a deeply human...


[User] Please transcribe this text

[Assistant] Rarely do we think of ourselves as citizens of states, but they did in the 19th century.


[User] Please transcribe this text

[Assistant] Journey to the West, Chapter 65, The Metal Ring.


[User] Please transcribe this text

[Assistant] Then the demon dragged in Bajie and Wujing. They were still trapped in the vests.


[User] Please transcribe this text

[Assistant] Demanded Wu Jing from the corner. The demon turned to face him.


[User] Please transcribe this text

[Assistant] Said Bajie. The demon smirk disappeared.


[User] Please transcribe this text

[Assistant] The door flew open, and one horned buffalo stepped out.


[User] Please transcribe this text

[Assistant] He rushed at Wukong and the monkey swung his iron bar again. The demon blocked it with his arm. Bam!


[User] Please transcribe this text

[Assistant] One horned buffalo spun around, holding up the metal ring.


[User] Please transcribe this text

[Assistant] Nobody is missing from heaven. But I will arrest one horned buffalo for you.


[User] Please transcribe this text

[Assistant] But the demon stole my sword. I need more help.


[User] Please transcribe this text

[Assistant] I don't know why you need my help. I've heard you're quite strong. What kind of demon is it? It's a scorpion spirit.


[User] Please transcribe this text

[Assistant] I understand now. Lead the way. We must hurry.


[User] Please transcribe this text

[Assistant] I have special magic that I'll use to defeat the scorpion.


[User] Please transcribe this text

[Assistant] In sports you got the pros on one hand and on the other you got amateurs.


[User] Please transcribe this text

[Assistant] Lucille will play on my team, and Marcy will play on yours. See ya! We said Marcy plus a pizza patty.


[User] Please transcribe this text

[Assistant] Oh, Marcy, you have no idea how happy I am to be rid of Lu- That you are-


[User] Please transcribe this text

[Assistant] Actually Charles, I hate baseball.


[User] Please transcribe this text

[Assistant] Okay, Lucille. This next hitter is pretty good, so keep your eye on the ball. That's hard to do when you keep moving it around.


[User] Please transcribe this text

[Assistant] I'm happier standing here with you, Charles. Ahem. You gotta take Lucille back, Chuck. I wanna call the deal off. Impossible. Snoopy already ate the pizza.


[User] Please transcribe this text

[Assistant] What happens at a testimonial dinner? Well, everyone gets up and shizz-


[User] Please transcribe this text

[Assistant] I've been reading up on football sir. When you first asked me to play, I didn't know anything about it.


[User] Please transcribe this text

[Assistant] Okay, ball. Before I kick you, I want to apologize. I want you to know there's nothing personal in this. That I intend you no harm. That I hope this kick does you no injury. And that- PICK THE BALL, MARCY!


[User] Please transcribe this text

[Assistant] Master, I don't know why you're still going there. You should have married that scorpion spirit instead.


[User] Please transcribe this text

[Assistant] That's not funny, Wukong.


[User] Please transcribe this text

[Assistant] I know how we can get there soon, said Wukong with a laugh.


[User] Please transcribe this text

[Assistant] Ask the man. My name is Sun Wukong.


[User] Please transcribe this text

[Assistant] If you can pick this up, we'll give you all of our money. You're a fu-


[User] Please transcribe this text

[Assistant] But you need me, Master. Wukong insisted. I refuse to leave.


[User] Please transcribe this text

[Assistant] I know why you're here, Wukong. I also know who the demon is. You must go to Lausa for help.


[User] Please transcribe this text

[Assistant] He's my green buffalo. I didn't realize he'd escaped.


[User] Please transcribe this text

[Assistant] Okay, okay. I can capture the buffalo. Don't worry.


[User] Please transcribe this text

[Assistant] Well hello everyone and welcome to this English lesson about rudeness. Rudeness describes when people behave in a way that's not very nice or not very kind.


[User] Please transcribe this text

[Assistant] It's not nice to be rude, but as humans sometimes we are rude to each other. I'm even rude sometimes, believe it or not. So in this English lesson, I'll look at different words and phrases that we use when talking about rudeness, how we describe people who are rude,


[User] Please transcribe this text

[Assistant] The effects of that rudeness, uhm, and describing in general why something is rude or how it makes someone feel. So once again, I hope you're ready to learn English. Welcome to this English lesson about rudeness.


[User] Please transcribe this text

[Assistant] So the first word I have for you is inconsiderate. When you are inconsiderate, you do something that maybe helps you, but you aren't thinking about how it will affect other people. Here's a good example. This might be a little bit of a Canadian example.


[User] Please transcribe this text

[Assistant] When we shovel our driveways, when we clean our driveways, the snow needs to go somewhere.


[User] Please transcribe this text

[Assistant] Because it helps me. My driveway is nice and clean. But I just put all the snow on my neighbor's driveway. So that would be inconsiderate.


[User] Please transcribe this text

[Assistant] Another example of inconsiderate would be, sometimes we sit down to eat and one of my kids is thirsty and we don't have cups on the table. So they go and get a cup for themselves, but they don't get a cup for the other people. That would be inconsiderate.


[User] Please transcribe this text

[Assistant] The opposite would be considerate. When you're considerate, you think about other people when you do certain things.


[User] Please transcribe this text

[Assistant] A friend of yours was just in a car accident, and they found it really traumatic. They didn't get injured. And then if you showed them a video that you thought was funny of a car accident on your phone, if you were like, oh hey, look at this video of a car accident, that would be insensitive.


[User] Please transcribe this text

[Assistant] Because your friend is kind of upset because they just had a car accident a while ago. So it would be insensitive to show them that. So usually it's when you


[User] Please transcribe this text

[Assistant] Say something or do something without thinking about the other person and how they might feel.


[User] Please transcribe this text

[Assistant] Offensive. So this is not true. All Canadians are not mean, but it would be offensive if someone said,


[User] Please transcribe this text

[Assistant] It's just mean to another person or a group of people. It's offensive. So if you say something that's racist, it's offensive. If you say something about a group of people that isn't true, it's offensive.


[User] Please transcribe this text

[Assistant] Offends people. It's not nice to say things that are offensive. And by the way, all Canadians are not mean. Some Canadians are mean though.


[User] Please transcribe this text

[Assistant] That's just the way life is, isn't it? Some people are nice, some people are not. So, it's offensive when you say something that isn't true as well about a group of people or about a person.


[User] Please transcribe this text

[Assistant] Impolite. So when you are impolite, it's the opposite of being polite. It's when you don't say thank you when someone gives you something. It's when you take the biggest cookie. If someone offered you a cookie, and if you always take the biggest cookie, that's impolite.


[User] Please transcribe this text

[Assistant] We are always trying to teach our children to be polite. We're trying to teach our kids to say please and to say thank you, to share with each other, to not always take the biggest cookie. So when you do something like that, when you take the biggest cookie, you are being impolite.


[User] Please transcribe this text

[Assistant] When someone gives you something and you don't say thank you, you are being impolite. Not good to be impolite.


[User] Please transcribe this text

[Assistant] Bullying. Let's talk about a few actions that occur that are considered very rude. Some of these are even mean. So rude is a little less than mean. Like mean is...


[User] Please transcribe this text

[Assistant] Worse than being rude, I think. But bullying, bullying happens a lot between children. It's when one child or a group of children


[User] Please transcribe this text

[Assistant] Are just not very nice to another child. Maybe they steal their lunch. Maybe they yell at them at recess like in this picture.


[User] Please transcribe this text

[Assistant] Maybe they everyday just aren't very nice to them or call them names. All of that would be considered bullying and all of that would be very, very rude. Extremely rude is how I would describe that. Lying.


[User] Please transcribe this text

[Assistant] It is considered rude to lie. You shouldn't lie to your boss. You shouldn't lie to your spouse. You shouldn't lie in general. And I don't want to get into the details.


[User] Please transcribe this text

[Assistant] Uhm, but I do believe all humans lie. I don't mean to offend any of you. I don't, I hope that's not offensive for me to say that. But I'm pretty sure all humans lie at some point in their life. Maybe even


[User] Please transcribe this text

[Assistant] But yes, it's considered very rude to lie. If you call in sick to work, but you're not actually sick, that's kind of rude because it might mean other people at work have to do your job, um, while you're sitting around at home doing nothing. But if you are sick, if you're actually sick, you should call in.


[User] Please transcribe this text

[Assistant] So, there's a couple different ways to be rude with loudness. You can talk loudly.


[User] Please transcribe this text

[Assistant] So, loudness is definitely, yes, either your voice or playing music or anything else. Uhm, if you were to, I'm trying to think of another example.


[User] Please transcribe this text

[Assistant] Sometimes young people put really loud exhaust systems on their cars. So when they drive, the car's like, mrrr, mrrr, super, super loud.


[User] Please transcribe this text

[Assistant] So this is also a bit of a cultural lesson. Whenever I do lessons about how people behave or what kind of behavior is good or bad, it is really a lesson about Canada and North America. In other cultures or other countries, some of these things might not be root.


[User] Please transcribe this text

[Assistant] Staring is definitely rude in Canada. If you go and workout at the gym, while I'm lifting weights at the gym, I don't want someone to stare at me.


[User] Please transcribe this text

[Assistant] If I'm riding on the bus I don't want someone to stare at me. When you stare at someone you look at them intently. I think the last time I taught the word stare I did this.


[User] Please transcribe this text

[Assistant] That's a me acting out what staring looks like. Uhm, so it's considered quite rude, uhm, to stare at someone.


[User] Please transcribe this text

[Assistant] Interrupting. This is, this is one of the rude things that I do sometimes. Interrupting is when two people are talking and before someone is able to finish their sentence, you start talking.


[User] Please transcribe this text

[Assistant] Now in English, when you don't mind your own business, it means you are asking someone a lot of questions about their life or what they are doing. We have another word for this and it's the word nosy.


[User] Please transcribe this text

[Assistant] Sometimes people are nosy. Sometimes, I'm not sure if my mom is watching this, but moms, I think, are allowed to be nosy. Moms are allowed to do this and it's not rude.


[User] Please transcribe this text

[Assistant] If I was to ask someone a lot of questions about what they're doing at work,


[User] Please transcribe this text

[Assistant] And if it wasn't my job, they could say mind your own business.


[User] Please transcribe this text

[Assistant] They would think it's rude of me. It would be rude for me to say, oh, you're coaching basketball. Uhm, are you doing this, this and this? And in the last game, I noticed this, but you should probably change this. They might say,


[User] Please transcribe this text

[Assistant] It would be rude for them to say this though. They might say, hey, mind your own business. So speaking directly can also be rude, but yes, trying to


[User] Please transcribe this text

[Assistant] Tell someone how to do something or asking someone a lot of questions would be considered very rude. So yes, don't be nosy and you should mind your own business.


[User] Please transcribe this text

[Assistant] If someone wears, uhm, maybe they wear funny looking shoes or they have a funny hat.


[User] Please transcribe this text

[Assistant] Or maybe they get a haircut and other kids don't think it looks nice. They might make fun of that person. In English, when you make fun of someone, you laugh at them. You might point at them. You might be like, ha ha ha, Bob the Canadian. He has a funny haircut or ha ha Bob the Canadian. He has a gigantic nose. Like that would be rude.


[User] Please transcribe this text

[Assistant] I do have a bit of a big nose though. I'm allowed to say I have a bit of a big nose. I think it's because I'm from Northern Europe.


[User] Please transcribe this text

[Assistant] My ancestors probably all had big noses. Anyways, making fun of someone.


[User] Please transcribe this text

[Assistant] Uh, is considered rude, impolite, mean, there's a number of ways to describe it. And generally it happens with kids, but adults do it as well. They just don't usually say it to the person. They usually make fun of someone behind their back. So they talk about someone when they're not there. That's also rude, by the way.


[User] Please transcribe this text

[Assistant] Being disrespectful. So being disrespectful is rude.


[User] Please transcribe this text

[Assistant] Uhm, sometimes students are disrespectful. Sometimes students don't want to do their work or sometimes students will say


[User] Please transcribe this text

[Assistant] Is actually quite rude to their classmates. They say, uh, things that aren't appropriate in the classroom. So you need to be respectful. And if you are disrespectful, it is not a very, very nice thing. Very rude.


[User] Please transcribe this text

[Assistant] Gossiping. So this is something that adults might do more than kids.


[User] Please transcribe this text

[Assistant] Maybe the same. This is when you talk about someone when they aren't there.


[User] Please transcribe this text

[Assistant] And it also involves maybe saying things that aren't true about that person. So two of you might meet for coffee later today and you might talk about me and you might say,


[User] Please transcribe this text

[Assistant] You know, Bob the Canadian took two weeks off and he said he's teaching an extra class, but I'm not sure if that's true or not. Like when you start to.


[User] Please transcribe this text

[Assistant] Tell lies or exaggerate something about someone that isn't true. That's when you are gossiping and it's when you spread stories about someone. Not a nice thing to do. Very, very, very, very rude. Very rude.


[User] Please transcribe this text

[Assistant] Uhm, I'm not usually late. So this is one of the things that, uhm, by the way, if this lesson seems similar to the lesson on pet peeves, they do overlap a little bit.


[User] Please transcribe this text

[Assistant] Pet peeves are things that annoy, uhm, someone about other people. So, rudeness and pet peeves kind of go together.


[User] Please transcribe this text

[Assistant] So one of my pet peeves is I don't like it when people are late. I am almost always on time. If we have a meeting at school, if we have a meeting at work, I'm usually one of the first people there and then I think it's rude


[User] Please transcribe this text

[Assistant] When people come late. I hope my coworkers aren't watching. But I think it's a pretty standard thing to say, that being late is very, very rude and somewhat impolite.


[User] Please transcribe this text

[Assistant] Uh, littering. So littering is not a nice thing. Some of you, because of where I shoot my videos, might think that Canada is a beautiful country with no litter anywhere. That's usually because I choose


[User] Please transcribe this text

[Assistant] When people are driving along and they finish their coffee and they throw the cup out the window. I think that's very rude.


[User] Please transcribe this text

[Assistant] It's rude to the people who have to see the litter, and it's rude because we all need to work hard to take care of this planet. So, littering, very rude, quite rude.


[User] Please transcribe this text

[Assistant] Tailgating. So there are a number of things that people do while driving that can be considered rude.


[User] Please transcribe this text

[Assistant] Uh, tailgating is when you drive too closely behind someone else.


[User] Please transcribe this text

[Assistant] Should leave some space when you're behind someone, just in case the person in front needs to stop quickly or for some other reason.


[User] Please transcribe this text

[Assistant] But tailgating is considered rude. Uhm, cutting someone off is considered rude. Do you remember the lesson on driving? There are a few things people do. So if you drive past someone and pull really quickly in front of them, that's very, very rude.


[User] Please transcribe this text

[Assistant] I consider it rude when someone drives too slowly. The other day I was driving to school and the speed limit is 80 kilometers an hour.


[User] Please transcribe this text

[Assistant] And I usually do about 90. That's okay in Canada. You won't get a ticket for going five or 10 kilometers an hour over. And the person in front of me was doing 60. That was, I thought that was a little bit rude. So a few things you can do while driving that are considered rude. One is tailgating someone.


[User] Please transcribe this text

[Assistant] So this is an interesting one, because it depends where you are.


[User] Please transcribe this text

[Assistant] When I was younger, when I was, uh, 17, 18, 19, uh, in the summer, I would help build houses. I was a construction worker and it was very common for people to swear at work. So while we were building a house or a barn, my coworkers would swear and it was kind of normal.


[User] Please transcribe this text

[Assistant] Uh, what in English we call four letter words. There's a few of them. One starts with F and ends with K. I think you might know that one. Um, but it is very rude.


[User] Please transcribe this text

[Assistant] A restaurant, if you are on the train, it would be considered somewhat rude to swear a lot. People do swear every once in a while, but if every 10th word is a swear word and you're doing that in public where other people can hear you, it would be considered quite.


[User] Please transcribe this text

[Assistant] Taking credit. So this one, this might take a little time to explain. When you take credit, I mean, it's rude when you take credit for something you didn't do. In English, when you take credit for something, you say, I did it. So if you were to say, Bob, who


[User] Please transcribe this text

[Assistant] Uhm, who writes your English lessons for you? I could say I write my own English lessons. I have ideas and I create them. But if someone else


[User] Please transcribe this text

[Assistant] Was doing the work and I said I did it. That would be taking credit for something I didn't do.


[User] Please transcribe this text

[Assistant] This does sometimes happen at work, not my work, very rare at my work, but sometimes you will do something at work and someone else will tell the boss they did it. Someone will take credit for something you did.


[User] Please transcribe this text

[Assistant] Does a great job on a project and you go to the boss and say, I did that project.


[User] Please transcribe this text

[Assistant] It's, it's a lie as well, right? Uhm, if you take credit for it, very rude. Don't take credit for things that you don't do. Blocking the aisle.


[User] Please transcribe this text

[Assistant] This happens in our one grocery store because it's very, very small. The aisles are very, very narrow.


[User] Please transcribe this text

[Assistant] Uhm, you should always be aware of people in front.


[User] Please transcribe this text

[Assistant] Even more rude is this did happen to me.


[User] Please transcribe this text

[Assistant] A few months ago now, someone had AirPods in and they were playing their music really loudly and they were blocking the aisle. So when I said, excuse me, can I get through? They couldn't hear me. So they were rude twice, once because they were blocking the aisle. Uh, and the second rudeness would be that they couldn't hear me.


[User] Please transcribe this text

[Assistant] By the way, I should have included that slide maybe. I don't have that one, but sometimes it's rude when people have their music so loud they can't hear the people around them. Sniffling. So this is an interesting one.


[User] Please transcribe this text

[Assistant] Any visual signs of sickness are considered quite rude. In Canada, I'm not sure what it's like in your countries, but because of the pandemic, if you are sick, you generally stay home from work now, very quickly. Uhm, if you have a bad cough, like, if you have a stuffed up nose, uhm,


[User] Please transcribe this text

[Assistant] Any sign of sickness, it's considered rude to go where other people are. I would say before the pandemic, this was not necessarily the case. If you were sick, you were just sick, people would stay far away from you. But now at school, if a student or teacher comes in and you can tell they're sick,


[User] Please transcribe this text

[Assistant] Uh, people consider that very, very rude. Like just stay home. If you're sick, stay home.


[User] Please transcribe this text

[Assistant] Double dipping. So I don't know if you're familiar with this one, but if I


[User] Please transcribe this text

[Assistant] In Canada, not sure what it's like in the rest of the world, if I have a chip and we have hummus or salsa,


[User] Please transcribe this text

[Assistant] or something to dip the chip in. If I take a chip and dip it in and take a bite


[User] Please transcribe this text

[Assistant] People don't like it if you dip again, if you double dip. So if you have crackers or chips, and you, uh, you dip, eat, and then you, with the piece that you bit, so you have half a cracker now, if you dip again, that's considered rude, and we call it double dipping.


[User] Please transcribe this text

[Assistant] So if you go to a party and you are eating food, maybe you're eating pitas or you have nans or some sort of, uh, bread or cracker or chip that you're dipping. Dip once and eat. Don't dip again. You can get a new chip.


[User] Please transcribe this text

[Assistant] And dip that. That's fine. That's not double dipping. It's when you use the same chip or cracker twice. Very rude to double dip.


[User] Please transcribe this text

[Assistant] Being critical. When you're critical of someone, it means you're telling them what they're doing wrong. When, uhm, one of my kids washes the dishes, if I say, hey, there's still food on this plate, uhm, I'm being a little bit critical. Uhm, it's more than that though. I think it would be if, even when


[User] Please transcribe this text

[Assistant] Let me see, how would I describe being critical? It means you always think someone is doing something wrong and you rarely think they're doing it right. So when I say good job or I say bad job, when I say good job, I'm being positive. When I say bad job, I'm being critical.


[User] Please transcribe this text

[Assistant] Uhm, sometimes it's okay to be critical, but if you're always critical, it can be...


[User] Please transcribe this text

[Assistant] Challenging. It can be difficult. Uhm, some people have parents who never think the children as adults are making good decisions and they are very, very critical of them. Not very nice.


[User] Please transcribe this text

[Assistant] Uhm, not helping clean up. So this is considered rude in Canada. I'm not sure what it's like in your country. But if I go to my sister's place for a meal, when we're done eating, I help clean up.


[User] Please transcribe this text

[Assistant] When my family gets together here and we have a campfire, when we sit around a campfire, at the end of the evening, everyone helps clean up.


[User] Please transcribe this text

[Assistant] We put out the fire, we put the chairs away, we pick up all the garbage. When you visit someone, at least in Canada, I think in most places in the world,


[User] Please transcribe this text

[Assistant] It's polite to help clean up. If I go to, uhm, my brother-in-law and sister-in-law's place and I eat a big meal, and when the meal's done, I watch them clean up, that would be rude. It would be polite for me to say, hey, uhm,


[User] Please transcribe this text

[Assistant] I'll put a few things away. That's usually what I do or put the dishes in the dishwasher.


[User] Please transcribe this text

[Assistant] I don't put the dishes in the dishwasher when we visit. I usually pick up, I usually put the peanut butter away and I put the bread away. I, I do an easy job. Maybe I'm a little bit rude. Who knows.


[User] Please transcribe this text

[Assistant] Uh, arguing. Now, arguing can be fun. Some people like to argue. I have a good friend and we like to argue sometimes. Uhm, but sometimes it's rude to argue. Uhm, if the boss tells you to do something, it would be rude to argue with the boss. Okay? Uh, so again, arguing is when two people


[User] Please transcribe this text

[Assistant] To sometimes argue. Sometimes it's not rude though. This is a tricky one, because arguing can be fun. Uhm, we teach students how to argue formally in a class. Like, it's more of a debate then, but arguing can sometimes be rude.


[User] Please transcribe this text

[Assistant] Talking about yourself. So I do this a little bit.


[User] Please transcribe this text

[Assistant] Uh, it can be rude. When you are having a conversation with someone, it's always best to ask them about their life and listen to what they're saying. It's not nice to have a conversation with someone where


[User] Please transcribe this text

[Assistant] They just talk about themselves. So sometimes I'll do this. I'll say to someone, how's it going? And they'll tell me how it's going. And then I'll just start talking about myself.


[User] Please transcribe this text

[Assistant] I think I'm explaining this badly, but if you know someone where whenever you talk to them,


[User] Please transcribe this text

[Assistant] 90% of the conversation ends up being about them. That would be a little bit rude, talking about yourself.


[User] Please transcribe this text

[Assistant] And this is a similar one, bragging. So if I was like, oh, look at the size of my muscles, or I, I uhm, I'm trying to think of something to brag about.


[User] Please transcribe this text

[Assistant] I'm not, this is not one of my faults. I don't brag. I talk about myself a lot, but bragging is when you say, oh, Jen and I grow more flowers than any other farm in Ontario. That's not true by the way, but bragging is when you talk about yourself and you talk about the things you're good at repeatedly over and over again.


[User] Please transcribe this text

[Assistant] Reaching. So this is something we try to teach our kids not to do. Uhm, in Canada, when you're having a meal,


[User] Please transcribe this text

[Assistant] A better thing to do would be to ask someone to pass something. So you would say, please pass the milk, please pass the potatoes and they will hand it to you. So reaching a little bit rude.


[User] Please transcribe this text

[Assistant] Budding. So this is also called cutting in line or jumping the queue, I think in Britain. Don't quote me on that. Uh, in English, uh, a more informal term is simply budding. It's when there's a line of people and instead of going to the back of the line, you try to bud.


[User] Please transcribe this text

[Assistant] I'm assuming this is different in different parts of the world. I don't know. But I think most people in Canada will brush their teeth before they go to work. And most of us have


[User] Please transcribe this text

[Assistant] Good oral hygiene, we would call it. That's the dentist term. Good oral hygiene. It's not nice to have bad breath. It's not nice to work with someone who has bad breath. Uhm, it can be very, very rude and uncomfortable to work with someone. So again, bad breath is when


[User] Please transcribe this text

[Assistant] You breathe out and it just doesn't smell good for some reason. Bad breath.


[User] Please transcribe this text

[Assistant] Whenever I talk about burping and farting, it makes me giggle a little bit. Burping is something that in some places might not be rude.


[User] Please transcribe this text

[Assistant] In Canada, it's definitely rude, I think, to burp, especially if you burp quietly with your hand here. So burping is when you've eaten some food and you, um, yeah, I don't want to, it's like, ehh, you make, you let air out of your stomach.


[User] Please transcribe this text

[Assistant] I think if I was to burp quietly with my hand here that would be okay, but if I was to burp


[User] Please transcribe this text

[Assistant] Like with my mouth wide open, so it's really loud. That would be rude. Uh, and farting.


[User] Please transcribe this text

[Assistant] And how uhm, everyone lies. I think farting is like lying. I think everyone in the world, uh, does this at some point. For sure.


[User] Please transcribe this text

[Assistant] Yelling from another room. Uh, so this is something I do. And, uh, I think it's a little bit rude. Sometimes I'll be in this room, working, and our kitchen is right beside. And Jen will be in the kitchen, and I will, I will yell to Jen. I will say, hey,


[User] Please transcribe this text

[Assistant] What time does one of the kids need to be at school tomorrow and so it would be more polite to get up and go to the same room Jen is in and quietly ask her.


[User] Please transcribe this text

[Assistant] But instead I tend to yell. Maybe that's why I lose my voice a few times a year, because I'm always yelling questions.


[User] Please transcribe this text

[Assistant] Hey, what time are you going? I don't know. I can't think of an example question right now.


[User] Please transcribe this text

[Assistant] Not answering a question. So this is interesting. Some, this happens more between parents and kids or teachers and students where you're talking to a child or a student and instead of answering your question they ignore you.


[User] Please transcribe this text

[Assistant] Ignoring someone can be very, very rude. If I say to a student, why are you late for class? And if they just walk by me and sit down without responding, that would be very, very rude. So it's always good.


[User] Please transcribe this text

[Assistant] Especially in those situations where an adult is in charge, you should answer the question. Ignoring someone I think would be considered quite rude.


[User] Please transcribe this text

[Assistant] One day you wake up and you're no longer the last of the bunch.


[User] Please transcribe this text

[Assistant] Master, you wait here while Barjay and I find a village.


[User] Please transcribe this text

[Assistant] I'm Sha Wujing. We were traveling to the west together. I'm going to the west, but not with you.


[User] Please transcribe this text

[Assistant] Journey to the West, Chapter 85, Fire, Smoke, and Sand.


[User] Please transcribe this text

[Assistant] He looked at the demon of Powers Mountain. The fire and smoke were now gone. Wukong was about to return to that mountain. But then he hesitated.


[User] Please transcribe this text

[Assistant] Wukong turned into a bug and flew back to the Demon's Mountain.


[User] Please transcribe this text

[Assistant] He went into the cave and flew down a long, dark tunnel.


[User] Please transcribe this text

[Assistant] The monkey turned back into a bug and flew down another tunnel.


[User] Please transcribe this text

[Assistant] Soon he found a second bedroom. This one was dark and gloomy.


[User] Please transcribe this text

[Assistant] A little while later, the Demon of Power came into the room.


[User] Please transcribe this text

[Assistant] He plucked a few of his hairs and turned them into fleas.


[User] Please transcribe this text

[Assistant] The demon laid the three bells on a table. A few minutes later, he was snoring again.


[User] Please transcribe this text

[Assistant] Wukong became invisible and ran back through the tunnel.


[User] Please transcribe this text

[Assistant] We understand that we can actually control the density of charges, charge, uh, carriers, free charge carriers on the surface. And particularly we can actually use the process of inversion.


[User] Please transcribe this text

[Assistant] Right? So now think about it, you have a surface whose conductivity or charge density you can control. Now if you can control the charge density, you can control the conductivity. Right? And if you can control the conductivity, you can actually modulate it.


[User] Please transcribe this text

[Assistant] So the device we are going to construct is called a MOSFET. FET stands for Field Effect Transistor.


[User] Please transcribe this text

[Assistant] Sometimes in shorthand you refer to it as MOS transistor or CMOS. CMOS is not really a transistor, it's a process, complementary metal oxide semiconductor process. But a lot of times people refer to it as CMOS transistor. Fine.


[User] Please transcribe this text

[Assistant] But the more technically accurate name would be a field effect transistor.


[User] Please transcribe this text

[Assistant] Because you are applying an electric field that would induce carrier concentration. So,


[User] Please transcribe this text

[Assistant] How do we do that? So let's think about it this way. So let's say you have the surface, and let's say this time you start with a p-type bulk.


[User] Please transcribe this text

[Assistant] To induce inversion charge, now you have to make apply a positive charge to the gate, which would repel the electron, the holes away, and eventually will form an electronic layer of inversion charge at the surface.


[User] Please transcribe this text

[Assistant] This is not the way a real mosfet today looks like. The gate of a real mosfet. The real mosfet, and I will, let me draw the rest of it and I will show you what kind of the cross section of it looks like.


[User] Please transcribe this text

[Assistant] Uh, it's a little bit different, but we'll use the same thing because it essentially gives you the same physics. The drawing doesn't matter.


[User] Please transcribe this text

[Assistant] Is this a transistor? So I have a gate. Let's say V gate. V, some voltage here on the gate. Is this a transistor?


[User] Please transcribe this text

[Assistant] Yeah, you need a place to connect the actual resistance. So where is the place where we are actually modulating stuff? We're modulating the carrier concentration here. So it would make sense to have something on each side that will allow us to make contact with this thing.


[User] Please transcribe this text

[Assistant] And it does actually more than that, we'll see. So what kind of doping should be put in there if you want to make a contact that


[User] Please transcribe this text

[Assistant] Allows you to make a contact, but it's something that can be turned on and off.


[User] Please transcribe this text

[Assistant] When it's on, what kind of channel am I forming when I do inversion in the p-type material? What kind of charge carriers will I have? Electrons, right? On the surface.


[User] Please transcribe this text

[Assistant] And these electrons are basically, essentially turn the surface into an n-type material.


[User] Please transcribe this text

[Assistant] So, if you want to make a ohmic contact to an n-type material, what kind of material would you use? n-type.


[User] Please transcribe this text

[Assistant] Right? So, you basically put some n and n here. Now, if you think about it,


[User] Please transcribe this text

[Assistant] You want these contacts to be as low resistivity as possible. Because these contacts should not add resistance to the channel. So you can make them N plus. Or N++. Pretty high concentration, right?


[User] Please transcribe this text

[Assistant] What happens is that now you apply an electric protect. But the other interesting thing that happens when you do that is that if you do not have a voltage that's sufficient to form an inversion.


[User] Please transcribe this text

[Assistant] What do you have between here and there, if you think about it?


[User] Please transcribe this text

[Assistant] What do you have here? What is this? Between... Say again?


[User] Please transcribe this text

[Assistant] Negative I, yea correct, no no, I'm saying what kind of device do you have? If I look at this locally between this N plus and this P bulk, it's a diode, it's a P and junction diode, right? So you have two back-to-back diodes if you think about it.


[User] Please transcribe this text

[Assistant] Now why does that matter? Because it's that in the absence of a channel, there will be no current conduction. So this transistor can be turned off. If there is no inversion charge form, you have two back-to-back dials. Which doesn't carry that much current.


[User] Please transcribe this text

[Assistant] So, so that's actually a good thing because a useful device can be turned on and off.


[User] Please transcribe this text

[Assistant] Okay, so one of these, you can see this is a symmetrical device, the way it's drawn. So we can define one of them as a reference potential. In this case, this one. We define it as ground. And we call this the source.


[User] Please transcribe this text

[Assistant] And we'll see why it's called the source, more accurate, because it's the source of the charge in the channel. Now, there's a, so now you apply a potential


[User] Please transcribe this text

[Assistant] Voltage, electric potential here, to the gate. So, we call this VGS. Now everything is reference to the source, because that's the ground.


[User] Please transcribe this text

[Assistant] And then you have another electric potential here, Vds, the voltage between these two terminals.


[User] Please transcribe this text

[Assistant] And actually, you know what? If you think about this device, this is really not even a three terminal device. It's a four terminal device, exactly, right? Where is the fourth terminal?


[User] Please transcribe this text

[Assistant] So there's another voltage here, which we call VSB. Resource bulk.


[User] Please transcribe this text

[Assistant] So, what happens here is that in normal operation, well, before you apply a gate voltage, what do you have? You have depletion region formed here.


[User] Please transcribe this text

[Assistant] And of course this being n plus, most of the depletion is going to be on this end. Uhm, and what else? What else happens? Not much. If the VGS is below threshold, there's no inversion.


[User] Please transcribe this text

[Assistant] You have some depletion and that's the thing. But the one key question is that what is the threshold voltage in terms of these voltages? Is it the same, is it still the same VT0? You remember we defined this VT0, we found it to be the V-flat band plus 2 phi f plus gamma square root of 2 phi f.


[User] Please transcribe this text

[Assistant] So which one is this? Is this the voltage across the semiconductor or the oxide?


[User] Please transcribe this text

[Assistant] Semiconductor, right? By definition of the strong inversion. This came from the definition of strong inversion being that the surface potential


[User] Please transcribe this text

[Assistant] And this is the part inside the oxide. Now, people get confused because the parameters of gamma are such that they look like the parameters of the depletion region.


[User] Please transcribe this text

[Assistant] If I increase this voltage or decrease it, what, what, what is the thing that will change?


[User] Please transcribe this text

[Assistant] This depletion region, right? Because this is a p-n junction. This really controls, I'm controlling the, the reverse bias, if you will, of this p-n junction.


[User] Please transcribe this text

[Assistant] Now, this is a little bit of a tricky question, but I want you to think about it carefully.


[User] Please transcribe this text

[Assistant] It would affect one of these two terms. It wouldn't affect this because this is determined by some physical properties of the material and the charge we've implanted and things of that sort. One of these two will be affected.


[User] Please transcribe this text

[Assistant] Okay. And how many people think that this one will be effect? Okay. Let me ask you a question. What determines the value of this term?


[User] Please transcribe this text

[Assistant] Correct, it's defined in terms of the looping level of the concept. But it really came from, you're right, but it really came from the definition of strong inversion.


[User] Please transcribe this text

[Assistant] By definition of strong inversion, when we have this surface potential, we are in strong inversion.


[User] Please transcribe this text

[Assistant] So if we define our threshold as the point where the strong inversion happens, then this cannot change.


[User] Please transcribe this text

[Assistant] This is the definition of strong inversion, whatever the strong inversion is. So this is the one that will have to change. Now, how would it change?


[User] Please transcribe this text

[Assistant] So when you apply this voltage, you're changing what the surface potential...


[User] Please transcribe this text

[Assistant] The, the amount of the depletion charge you have here.


[User] Please transcribe this text

[Assistant] And that change in the electric field across the oxide makes it more slanted, which basically means that this term needs to be adjusted. You need more or less voltage on the gate.


[User] Please transcribe this text

[Assistant] So what it means is, from a practical standpoint, it means that this gets adjusted by VSP.


[User] Please transcribe this text

[Assistant] So now, this is not VT0 anymore. This is VT.


[User] Please transcribe this text

[Assistant] This is the threshold voltage, so that prime and zero went away.


[User] Please transcribe this text

[Assistant] And this is the threshold voltage for a device. More...


[User] Please transcribe this text

[Assistant] Often shown actually like this, so more frequently it's shown as vt, as vt0 plus gamma times square root of 2vf plus vsb minus square root of 2vf. And you can see this is basically a correction, it's a modification to vt0. So vt0 is a parameter


[User] Please transcribe this text

[Assistant] That, for example, when you're designing, you're given for a transistor. So you can say, this transistor is designed or is made to have a VT of 0.6 volts. 0.4 volts, whatever you have. So, it's gonna have a VT, zero.


[User] Please transcribe this text

[Assistant] But that vt is actually a function. The practical vt is changed.


[User] Please transcribe this text

[Assistant] In fact, as we'll see later on, and we'll discuss this in more details later, there are really two transistors here. In parallel. There are two transistors that are sharing the drain and source.


[User] Please transcribe this text

[Assistant] And there's a second controlling terminal, which is this bulk. It's called the body effect.


[User] Please transcribe this text

[Assistant] And then you can, actually by controlling this, you can control, it's kind of more like a JFET. If you think about it.


[User] Please transcribe this text

[Assistant] And sometimes this is a bad thing, you're trying to get rid of it, sometimes you can use it.


[User] Please transcribe this text

[Assistant] And we'll see in circuits when we discuss the actual circuit design.


[User] Please transcribe this text

[Assistant] But there's a second transistor really there, which is modulating a thing through modulating this ground. It's not a very strong one, as you can see from that square root dependence, but it is there.


[User] Please transcribe this text

[Assistant] And it can be a problem. The problem usually arises in circuit design when your source is not grounded. So if your source is moving, with this bulk you usually ground.


[User] Please transcribe this text

[Assistant] Then the potential difference between the source and the bulk will start modulating the threshold of the transistor.


[User] Please transcribe this text

[Assistant] And that's that second back gate transistor. We call it the back gate transistor sometimes. So it's important to understand where it comes from. This is where it comes from.


[User] Please transcribe this text

[Assistant] Now, you're forming a channel. You form a channel when you apply a gate voltage. So now first assume that VDS is very small. VDS very small. So the question is, what is


[User] Please transcribe this text

[Assistant] The current flowing, let's call it I-drain or I-transistor which will be flowing out of here as a function of VGS and other parameters in the circuit.


[User] Please transcribe this text

[Assistant] Well, really to think about this, we have to really turn this into a three dimensional structure. I mean, we have to see the three dimensional structure fully.


[User] Please transcribe this text

[Assistant] So let's say this length, this length is called, this is L, and this is the width of the transistor W.


[User] Please transcribe this text

[Assistant] Well, we talked about the inversion charge, right? We said storing inversion charge to inversion was C-ox


[User] Please transcribe this text

[Assistant] Gate oxide per unit area, Vgs minus Vt. Now we can use this Vt. So that's the charge in the channel. Okay?


[User] Please transcribe this text

[Assistant] Now, how long does it take an average electron, because electrons start from the source, and that's why it's called the source, because it's the source of charge carriers. If you had a p-met, p-fet, which is the opposite of this thing, is p plus inside an n-type.


[User] Please transcribe this text

[Assistant] Uh, well or substrate, then what happens is that you will have holes. So the holes are, when you apply a voltage, are coming from here. Now, this is one fundamental difference between a MOSFET and a MOSCAP. You remember we said that the charge


[User] Please transcribe this text

[Assistant] If we were to account, if we were to use or count on that process, MOSFETs would have never been used as extensively as they are. Because they would have been very slow.


[User] Please transcribe this text

[Assistant] And none of the major electronic devices that you carried you would have happened.


[User] Please transcribe this text

[Assistant] That charge has to come from somewhere. Now it's different. The situation is different. Now you have actually a very large supply of these charges.


[User] Please transcribe this text

[Assistant] Where did they come from, the inversion charges? In this case they would be electrons, right? It's a p-type. Yes, from these two guys. There's a massive supply of electrons right next door. So you apply the voltage.


[User] Please transcribe this text

[Assistant] Right? You apply a positive voltage here, you start attracting negative charge. But they are not thermally generated charge. They are just coming from, they pour in from these two, the drain and source. Because you have a ton of them there. So they form a channel. And the charge in this channel is this. Let's say, that's the, so that's Q inversion, density, so the Q


[User] Please transcribe this text

[Assistant] It's gonna be WL, the area, times that areal charge density. So that would be the charge, the net charging coulomb. Now, to determine the current, approximately,


[User] Please transcribe this text

[Assistant] What do I need to do? It's gonna be this charge divided by the time it takes an average electron to get from this side to that side, right? What is that time?


[User] Please transcribe this text

[Assistant] What is the time it takes an average electron to go from one side to the other? Well, the time it takes to travel the distance L is the distance divided by the velocity.


[User] Please transcribe this text

[Assistant] So, what kind of velocity should I put there? I cannot give you a clue of course.


[User] Please transcribe this text

[Assistant] The electric field, and that electric field is induced by this voltage, right? So you apply a little bit of voltage here, so this becomes more positive than that, so the electrons are attracted across here.


[User] Please transcribe this text

[Assistant] So, what is that drift velocity? We know that drift velocity, we had an expression, in low field conditions, the drift velocity was proportional to the electric field inside a semiconductor, right? We discussed this.


[User] Please transcribe this text

[Assistant] So, and that proportionality constant was called what? Mobility. So it's mu and e.


[User] Please transcribe this text

[Assistant] Let's say it's uniform now. Let's say, I mean, we'll get to the non-uniform soon, but,


[User] Please transcribe this text

[Assistant] This is, let's say it's uniform. So you have applied the voltage ds. So this voltage is vds. What is the electric field inside, if it was uniform? It's vds divided by L, right?


[User] Please transcribe this text

[Assistant] So that's the time, that's the average transit time for electron. So that's the average, it takes an average, the time it takes an average electron due to drift to get from here to there. Or the average velocity of the electronic gas. That's induced by inversion.


[User] Please transcribe this text

[Assistant] Right? We've inverted the surface, and then that's it. So, now I think that we know how, we know everything we need, right? We, we, so we divide these two, next is algebra.


[User] Please transcribe this text

[Assistant] Now, this, remember, this is still for small VDSs.


[User] Please transcribe this text

[Assistant] If you think about it, if you look at Ohm's law, it's actually in this region, it looks like a resistor. There's a current that's proportional to the voltage across these two terminals, VDS.


[User] Please transcribe this text

[Assistant] But it's a resistor whose value is controlled by what? By the controlling terminal, the VGS. So you can actually modulate


[User] Please transcribe this text

[Assistant] And that's why it's called a transistor. Trans-resistor.


[User] Please transcribe this text

[Assistant] This is really the closest it comes to what the name transistor suggests.


[User] Please transcribe this text

[Assistant] Uhm, I should, next time I'll make copies of, as a handout of the three patterns of Julian and Lillianville, Julius Lillianville. They are very clear. There's no ambiguity.


[User] Please transcribe this text

[Assistant] Okay, by the way, Bell Labs paid, this is an interesting story, Bell Labs paid an undisclosed amount to Julius Lilienfeld.


[User] Please transcribe this text

[Assistant] When they had the big announcement for the transistor that Shockley, Barden and all those things invented.


[User] Please transcribe this text

[Assistant] I'm out. But it's in the record. Just go to the patent office, type Julius Lillianfield. He will, he will, pops up. All three of them.


[User] Please transcribe this text

[Assistant] Anyway, so this is the basic transistor. So now what we need to do is the next step for this is really to turn this into a more


[User] Please transcribe this text

[Assistant] Elaborate equation. So what we'll do next, we'll see that as VDS increases,


[User] Please transcribe this text

[Assistant] The current versus voltage. And we'll see that there are two regions of operation. This is what we call a triode region. Or linear region. Or ohmic region. And there will be another region which we'll call pinch-off region.


[User] Please transcribe this text

[Assistant] for operation of the monster. And we'll see where they come from and we'll see what the impacts are on the device and behavior of that.


[User] Please transcribe this text

[Assistant] Our leaders want all the troops to watch for him.


[User] Please transcribe this text

[Assistant] There are thousands of troops in our army. We'll all get to eat him.


[User] Please transcribe this text

[Assistant] The monk is just a man. He can't possibly stop us. I've heard that the tag monk isn't alone.


[User] Please transcribe this text

[Assistant] Just tell the troops to watch for the Tang monk. Yes, General.


[User] Please transcribe this text

[Assistant] We've got a couple of launches of Falcon Heavy later this year, so this had to go right. It was the first time we flew it.


[User] Please transcribe this text

[Assistant] And the star of the show, of course, brother and sister side boosters, Landing. I was excited.


[User] Please transcribe this text

[Assistant] And I read it, and sure enough, my first job out of my mechanical engineering degree was with Chrysler Motors in the automotive industry. But I actually got into engineering not because of that book, but because my mom took me to a Society of Women Engineers event, and I fell in love with the mechanical engineer that spoke. She was doing really critical work, and I loved her suit.


[User] Please transcribe this text

[Assistant] So, actually selling rockets is all about relationships and making a connection with these customers. When you don't have a rocket to sell, what's really important is selling your team, selling the business savvy of your CEO. That's not really hard to sell these days.


[User] Please transcribe this text

[Assistant] Uhm, and basically making sure that any technical issue that they have or any concern you can address right away. So I think it was helpful for me to be an engineer. I think it was helpful to my role as running sales for Elon.


[User] Please transcribe this text

[Assistant] I actually sleep really well. I'm a good sleeper. That's my best thing.


[User] Please transcribe this text

[Assistant] I think the days leading up to our flying crew will probably be a little sleepless.


[User] Please transcribe this text

[Assistant] But really, fundamentally, safety comes in the design of the system that you're going to fly people on. And so we've been working for years, actually almost a decade, on this technology. We're taking the Dragon cargo spaceship and we're upgrading it to be able to carry crew.


[User] Please transcribe this text

[Assistant] As I said, we've been engineering in these safety systems, uh, for quite some time.


[User] Please transcribe this text

[Assistant] Had a bad day right below it. This is if there was an issue on the pad. We also will be doing another demonstration later this year on if we have an issue with a rocket during flight.


[User] Please transcribe this text

[Assistant] Capsule safety systems in the past have been like tractor pullers. And the reason we didn't want to do that is that puller needs to come off before you can safely reenter that capsule. So we wanted to get eliminate, in design, that possibility of failure.


[User] Please transcribe this text

[Assistant] I think there's a couple of things that have allowed, well there's a number, a million things actually that have made, allowed SpaceX to be successful. Uhm, the first is that we're kind of standing on the shoulders of giants, right? We got to look


[User] Please transcribe this text

[Assistant] Uh, the tank architecture, it's a common dome design. Basically it's like two beer cans stacked together, one full of liquid oxygen, one full of RP.


[User] Please transcribe this text

[Assistant] Uhm, and that basically saved weight, uh, it allowed us to, uh, basically take more payload for the same design. Uh, one of the other, uh, elements of the vehicle that we're flying right now is we do use densified liquid oxygen and densified RP, so it's ultra-cold.


[User] Please transcribe this text

[Assistant] Basically, it packs, it allows you to pack more propellant into the vehicle. It is done elsewhere, probably not to the degree that we do it, but it adds a lot of margin to the vehicle, which obviously adds reliability.


[User] Please transcribe this text

[Assistant] So I love working for Elon. I've been doing it for 16 years this year, actually. I don't think I'm dumb enough to do something for 16 years that I don't like doing. He's funny.


[User] Please transcribe this text

[Assistant] Uh, and fundamentally, without him saying anything, he drives you to do your best work. He doesn't have to say a word. You just want to do great work.


[User] Please transcribe this text

[Assistant] There's no question that Elon is very aggressive on his timelines, but frankly, that drives us to do things better and faster. I think all the time and all the money in the world does not yield the best solution, and so putting that pressure on the team to move quickly is really important.


[User] Please transcribe this text

[Assistant] And not immediately say out, blurt out, well that's impossible, or there's no way we're going to do that, I don't know how to do that. So you zip it, and you think about it, and you find ways to get that done.


[User] Please transcribe this text

[Assistant] And the other thing I realized, and it made my job satisfaction substantially harder. So I always felt like my job was to take these ideas


[User] Please transcribe this text

[Assistant] And kind of turn them into company goals, make them achievable and kind of roll the company over from this steep slope, get it comfortable.


[User] Please transcribe this text

[Assistant] And my job is to get the comfortable, close to comfortable, so he can push again and put us back on that slope. Then I started liking my job a lot more.


[User] Please transcribe this text

[Assistant] We actually don't chat very much about this particular project, not because we're hiding anything, but this is probably one of the most challenging, if not the most challenging project we've undertaken. No one has been successful deploying a huge constellation for internet broadband, or basically for satellite internet.


[User] Please transcribe this text

[Assistant] Uhm, and I don't think physics is the difficulty here. I think we can come up with the right technology solution, but we need to make a business out of it. And it'll cost the company about 10 billion dollars or more to deploy this system.


[User] Please transcribe this text

[Assistant] There's no question, not because it's so likely to happen, but the consequences of it happening are pretty devastating. You could basically spew a bunch of particles in orbit that could take out that orbit from being useful.


[User] Please transcribe this text

[Assistant] So, as a matter of fact, we are required to bring down our second stage after every mission so it doesn't end up being a rocket carcass orbiting Earth. So we do, you really need to be a good steward of that.


[User] Please transcribe this text

[Assistant] Now, but we're going to continue flying Falcon 9s and Falcon Heavies until there is absolute widespread acceptance of BFR.


[User] Please transcribe this text

[Assistant] But we are working on it right now. We're just not going to cancel Falcon 9 and Falcon Heavy and just put in place BFR. But ...


[User] Please transcribe this text

[Assistant] Yes, BFR can take the satellites that we're currently taking to orbit, to many orbits. It allows for even a new class of satellites to be delivered to orbit. Basically, the width, the diameter of the fairing is eight meters.


[User] Please transcribe this text

[Assistant] So you can think about what giant telescopes you can put in that, uh, in that fairing in that cargo bay, uhm, and see really incredible things and discover incredible things in space.


[User] Please transcribe this text

[Assistant] Uhm, we could have tossed that engine, uh, and built an entirely new engine for the Falcon 9. It would have been called something different, obviously, because Falcon 9 is nine Merlin engines. But instead of spending a billion dollars on a brand new engine, we put nine of them together on the back end of Falcon 9.


[User] Please transcribe this text

[Assistant] Flying. And so it was expensive to do, but it was a much more efficient path than starting from scratch.


[User] Please transcribe this text

[Assistant] You'll be on the BFR for roughly half an hour or 40 minutes. And the longest part of that, yeaah, it's so awesome.


[User] Please transcribe this text

[Assistant] The longest part of that flight is actually the boat out and back.


[User] Please transcribe this text

[Assistant] Oh no, it's definitely going to happen. This is definitely going to happen.


[User] Please transcribe this text

[Assistant] So Chris, so can you imagine us trying to convince a federal-range Air Force bases to take the incomers? Because we're doing it now, regularly, right? We're bringing the first stages back and we're landing them on federal property on an Air Force base. So I think doing it, I don't know, 10 kilometers out from a city, maybe it's only five kilometers out from a city.


[User] Please transcribe this text

[Assistant] So the first ship, the first BFR is going to have roughly 100 passengers. And let's talk a little bit about the business. Everyone thinks rockets are really expensive, and to a large degree they are. And how could we possibly compete with airline tickets here? But if you think about it, if I can do this trip in ...


[User] Please transcribe this text

[Assistant] Half an hour to an hour, I can do dozens of these a day, right? And yet a long-haul aircraft can only make one of those flights a day. So even if my rocket was slightly more expensive and the fuel is a little bit more expensive, I can run 10x at least what they're running in a day and really make the revenue that I need to out of that system.


[User] Please transcribe this text

[Assistant] I'm personally invested in this one because I travel a lot and I do not love to travel. And I would love to get to see my customers in Riyadh leave in the morning and be back in time to make dinner.


[User] Please transcribe this text

[Assistant] Yeah, I think it'd be between economy and business. But you do it in an hour.


[User] Please transcribe this text

[Assistant] But basically, you're going to lift off from a pad, you've got a booster as well as the BFS, the big falcon spaceship, going to take off.


[User] Please transcribe this text

[Assistant] The booster is going to drop the spaceship off in orbit, low earth orbit, and then return


[User] Please transcribe this text

[Assistant] Just like we're returning boosters right now. So it sounds incredible, but we're working on the pieces and you can see us achieve these pieces. So booster comes back. The new thing here is that we're going to actually land on the pad that we launched from. Currently we land on a separate pad or we land out on a boat.


[User] Please transcribe this text

[Assistant] It ends up depending on how big the rocket is. I think that this first version, and we'll continue to make even bigger BFRs, I think it's a three-month trip. Right now, the average is like six to eight, but we're going to try to do it faster.


[User] Please transcribe this text

[Assistant] Very, very similar time frame from the point to point. It's the same capability. It will be within this decade. Within a decade. Not this decade.


[User] Please transcribe this text

[Assistant] So, I am glad you asked that, but I think we need to expand our minds a little bit. There are plenty of things to do on earth, but there are lots of companies working on that. I think we're working on


[User] Please transcribe this text

[Assistant] One of the most important things we possibly can, and that's to find another place for humans to live and survive and thrive. If there were to have something, if something happened on Earth, you need humans living somewhere else. It's, it's, it's ...


[User] Please transcribe this text

[Assistant] Making our planet here better and doing a better job taking care of it. But I think you need multiple paths to survival, and this is one of them. And let's not talk about the downer piece, like you go to Mars to make sure, you know, all earthlings don't die. That's terrible, actually. That's a terrible reason to go do it.


[User] Please transcribe this text

[Assistant] Fundamentally, it's another place to explore, and that's what makes humans different from animals, is our sense of exploration and sense of wonderment and learning something new. And then I also have to say,


[User] Please transcribe this text

[Assistant] Our focus would be, last time we talked about the bipolar transistors in great detail, so now we're going to talk about the MOSFETs. And in the process, one of the important things to think, to observe, is what are also the commonalities and what are the differences? And where do they come from? And what are the implications for the design?


[User] Please transcribe this text

[Assistant] As you will see, these commonalities, these commonalities and differences will have implications for the design. As will, uhm, the


[User] Please transcribe this text

[Assistant] The ways that you implement things as an, uh, as a discrete device. So.


[User] Please transcribe this text

[Assistant] Having said that, let's start with the MOS amplifier. We've done, when we did the parallel treatment of the basic common source and common emitter, and also we talked about the ATD, arbitrary three terminal device, we looked at the basic MOSFET amplifier, uh,


[User] Please transcribe this text

[Assistant] And what we did there very quickly was that, so if you had a common source,


[User] Please transcribe this text

[Assistant] With no degeneration, meaning no resistance in the source, you had a V in and V out.


[User] Please transcribe this text

[Assistant] That looks like this, and you had a resistance in RD, in the drain, and a VDD.


[User] Please transcribe this text

[Assistant] And what we saw is that essentially what you have, you can think about this, there's a, there's a quadratic behavior, or in more general, generally some sort of a nonlinear behavior, an index, velocity saturated, they can be even somewhat linear.


[User] Please transcribe this text

[Assistant] Regardless, there's a WL for the device, and then you have a VIN, VOUT. Let's say if it were quadratic, then this current, from a large-signal perspective, what was mu and Cox over 2, times W over L, times VIN minus VT, VGS minus VT of this guy.


[User] Please transcribe this text

[Assistant] What we'll get is that from a large signal perspective vout would be vdd, this voltage, minus the voltage drop across the resistor, which is rd times id. Now id is mu n cox over 2.


[User] Please transcribe this text

[Assistant] Minus VT, the threshold voltage, squared.


[User] Please transcribe this text

[Assistant] And if you ignore the channel length modulation, then this equation basically is a relationship between V in and V out. You can also throw in the channel length modulation, you can say 1 plus lambda V out, and then that becomes an equation that you need to solve. And you can solve that.


[User] Please transcribe this text

[Assistant] It just makes it a little bit more complex, but it doesn't add any additional insight. And we know these are approximate to begin with anyway. So if you look at the v in, v out DC characteristics, v in, v out.


[User] Please transcribe this text

[Assistant] What you see is something like this. You start from, if the VIN is zero, and assuming that the threshold is positive, this transistor is going to be off, so there's no current, so you're moving this way. Once you hit the VT, you start moving this way, and you, the transistor basically, you get the quadratic behavior of the transistor.


[User] Please transcribe this text

[Assistant] Until at some point, you get into the triad region.


[User] Please transcribe this text

[Assistant] It depends quite a bit on the parameters, right? So the question is, again, the same treatment. If you want to make this more linear, more controlled by the outside parameters as opposed to internal parameters of the transistor,


[User] Please transcribe this text

[Assistant] Now, one of the things, the other thing that, by the way, I should have said before I got to that one quickly, was this, the load line perspective. So basically this is if you have an ID versus VDS plot.


[User] Please transcribe this text

[Assistant] We know that they kind of look like that for a MOSFET. Here you are in the triode. And there you are in pinch-off.


[User] Please transcribe this text

[Assistant] And as you can see, as you change the V, these are for different VGS's, which are different VIN's, as you change the VIN, the operation point moves, and you go, your V, your output, which is the VDS, is going to go down. Which is, this is consistent with that picture on the left hand side.


[User] Please transcribe this text

[Assistant] So now, going back to the case of degeneration, we introduce, if we introduce a resistor in the source, let's call it RS, and you have an RD.


[User] Please transcribe this text

[Assistant] So that change in the threshold really is the change in the field that's appearing across the oxide. Because by definition of strong inversion, the surface potential has to be 2 phi f anyway.


[User] Please transcribe this text

[Assistant] Using the rule of thumb of whenever your source is not at a fixed potential, it's connected to another thing, T-model will usually help, works better. So let's use the T-model. The T-model we'll be using is gonna be a very simple one right now because we are ignoring


[User] Please transcribe this text

[Assistant] The body effect, and let's say we even ignore the channel length modulation.


[User] Please transcribe this text

[Assistant] RO. And we'll bring both of them back very quickly.


[User] Please transcribe this text

[Assistant] But let's just look at this first and see what we get. To get the core insight.


[User] Please transcribe this text

[Assistant] So, what is this resistance in the T model for the MOSFET? So this is basically source, right? And this is the drain.


[User] Please transcribe this text

[Assistant] So what is this resistance? What was it in the bipolar?


[User] Please transcribe this text

[Assistant] So this is let's call IS, and what is this current gonna be? It used to be alpha IE, so now it's alpha IS, it's gonna be just IS. And that makes sense because these two currents being equal, what would that make this current at low frequency? So it makes this DC current zero, which is what you expect to go into a gate anyway.


[User] Please transcribe this text

[Assistant] So that dependent source makes that current at low frequencies identically zero.


[User] Please transcribe this text

[Assistant] It forces it to be zero all the time. Which is what you expect from a MOSFET, right? I mean, if a classical MOSFET wall model you don't expect any DC current to go into that capacitor.


[User] Please transcribe this text

[Assistant] Of course we've talked about some of the non-idealities that arise from the thin gate oxide, there's tunneling current going into it, there are other things, and, and of course as we go to AC, then that's not the case, but for now that's what, what you have. So if you have this model, it's, and this is RS. So what is the gain of this? So the gain according to this model, it should be almost easy to determine by inspection, right?


[User] Please transcribe this text

[Assistant] We can use either the insides we derived last time, or we can do it directly. Let's do it directly and then talk about the insides briefly. So, the current Is is this voltage, you know this voltage is Vin, divided by these two resistors, right? So that's Is. And that Is is being pulled out of Rd, which is this resistor, Rd.


[User] Please transcribe this text

[Assistant] So the voltage drop across this thing is gonna be negative ISRD. Which is gonna be negative V in, so let's call that V out. It's gonna be negative V in divided by RS.


[User] Please transcribe this text

[Assistant] Plus Rm, which is this resistor, times Rd.


[User] Please transcribe this text

[Assistant] And therefore gain according to this is going to be negative rd over rs plus rm. Which,


[User] Please transcribe this text

[Assistant] Should make sense from an insight perspective, because the current in the drain and the current in the source are the same. Right?


[User] Please transcribe this text

[Assistant] So the voltage drop at the input appears across the source, which is divided by these two, and the voltage in the drain is determined by the current going through the drain. So the rule of thumb is the total resistance in the drain to the total resistance in the source, if you ignore all these other effects. Right?


[User] Please transcribe this text

[Assistant] So again, you have, in this case you have the negative of r drain total to the r source total. So again, if you are trying to design very quickly,


[User] Please transcribe this text

[Assistant] And amplify with a certain gain, the first thing, the first point we start with is a ratio. If you want to make this gain 10, you make this ratio roughly 10.


[User] Please transcribe this text

[Assistant] Okay, I didn't think about what RM is. So if your RM is 100 ohms, and then you make this ratio with a resistor of


[User] Please transcribe this text

[Assistant] Let's say 1 kilo ohm and 100 ohm, then you can expect your gain not to be 10, your gain would be 5. Because you have 100 plus 100.


[User] Please transcribe this text

[Assistant] You have the RM which was 100 and your explicit RS which is 100. So if you make it out of 10 kilo ohm and 1 kilo ohm, then you will get a ratio of 10 over 1.1 or 100 over 11. So you'll get 9 roughly. Instead of 10.


[User] Please transcribe this text

[Assistant] Or you can take that into account and make this whatever it needs to be and get that exact gait. If you're really looking for it.


[User] Please transcribe this text

[Assistant] But again, you wanna have this in the back of your mind in terms of when you're designing.


[User] Please transcribe this text

[Assistant] What are the primary first order things? So now, that's really first order. So let's make it a little bit more interesting. Let's add another idea. So let's now talk about actually what does the body effect do.


[User] Please transcribe this text

[Assistant] So let's add the body effect part, the body part. Now what is body effect? There's another way of thinking about it. Why would it be different? Well, because you essentially have a second transistor. You have that back gate transistor, right? So you have a circuit with two transistors operating not


[User] Please transcribe this text

[Assistant] And they share, these two transistors share the same drain and same source. They have different gates, but they share the same trans-


[User] Please transcribe this text

[Assistant] So the two transistors that share the same drain and change the same source, but they have different gates. So, and where is this gate connected? The back gate.


[User] Please transcribe this text

[Assistant] Well the back gate is connected to a fixed potential because it's basically connected to your substrate, generally. Now,


[User] Please transcribe this text

[Assistant] Depending on how you implement this transistor, this may or may not be the case. So let's talk about that briefly as a side note. The way these things, the most vanilla, the most standard way of implementing these,


[User] Please transcribe this text

[Assistant] Is that you have a substrate, so this is the cross-section of substrate.


[User] Please transcribe this text

[Assistant] The most basic transistor you make, and again, the modern processes may have more levels to this, is that you have an N plus, let's make this a different color I suppose.


[User] Please transcribe this text

[Assistant] So you have an n plus, and an n plus. And then this is a p-type substrate.


[User] Please transcribe this text

[Assistant] And then you have the gate oxide, and then you have the gate, so this is your NMOS, right?


[User] Please transcribe this text

[Assistant] So if you're doing this, this is connected to this gigantic sub, so the substrate, the back gate is connected to some ground. It's sitting on some sort of fixed potential, so your, your bulk is fixed. You cannot control the bulk independently. So you say, well, if my gate is fixed, why do I have to worry about this thing?


[User] Please transcribe this text

[Assistant] Well, you worry about it because of the bulk source voltage, like the gate source voltage that determines the thing. Yes, your bulk is fixed, but your source is moving.


[User] Please transcribe this text

[Assistant] So you are inducing a voltage across that controlling terminal of that back transistor, which would induce a change in the collector current, or the drain current in this case actually.


[User] Please transcribe this text

[Assistant] So, now the difference here is that the p-fets, so that's an n-fet, the p-fets again to create isolation, you need to create an n-well.


[User] Please transcribe this text

[Assistant] And what you do, you create an end well, and inside that end well,


[User] Please transcribe this text

[Assistant] You have a P+, and a P+, and then you also have to have an n-well contact.


[User] Please transcribe this text

[Assistant] So you have a contact here, and plus, that determines the potential. So now,


[User] Please transcribe this text

[Assistant] You have the ability to connect this to certain things. Of course, you want to make sure that you connect it to whatever you connect it doesn't forward bias this diode.


[User] Please transcribe this text

[Assistant] Because this diode, this reverse bias diode is used to isolate this transistor from other transistors. Right?


[User] Please transcribe this text

[Assistant] So that's what we call an n-well. It's made in a well. But one option you have is to connect it to your source.


[User] Please transcribe this text

[Assistant] So, in this very basic vanilla process, you have the option of attaching the source and the bulk to each other. And if you do that, you've essentially shorted across this RMB. Alright, because that's the source, that's the bulk.


[User] Please transcribe this text

[Assistant] Is gonna be zero, and therefore this current source is gonna disappear, so this effect is gonna go away.


[User] Please transcribe this text

[Assistant] You may say, okay, well that's great, I can get rid of it, at least for my PFETs. And that's true, you can get rid of it.


[User] Please transcribe this text

[Assistant] And there's a cost for it, which is that now your source sees a much larger capacitor, because now all the capacitors of this diode is also hanging off of your source. Which will have an impact on the speed. So there's a trade-off there. Again, we'll come back to this. I just wanted to kind of put, plant this in the back of your head.


[User] Please transcribe this text

[Assistant] Uh, process, we can't get rid of it. Actually, there are processes where you get, you get a duck twin well or twin top process where you can actually have separate wells for NFET and PFET and you can control them, uh, independently and bias them independently. So if you really need to get rid of the body effect, you can do it for N-well and P-well. That's an option on the process.


[User] Please transcribe this text

[Assistant] Let's go to this, and in this case, the way this is, so where is this connected? In the classical case. Where should I connect this terminal? To the ground, right? Because it's a fixed potential.


[User] Please transcribe this text

[Assistant] Right? All I need to do is just take this, rotate it and bring it down here. Take this, rotate it, bring it down here.


[User] Please transcribe this text

[Assistant] They're both ground. So I'm gonna leave my ground here. Take this, turn it around, flip it upside down.


[User] Please transcribe this text

[Assistant] One of the things I need to calculate is basically just total I s, right? This I s,


[User] Please transcribe this text

[Assistant] So that's the total current that comes out of the resistor, which determines my output voltage. So Vout is gonna be negative Rd times Is, which is Is1 plus Is2. That's the total current that's being pulled out of that resistor, right?


[User] Please transcribe this text

[Assistant] So now the other question is, how do we determine Is1 and Is2? Well, there's a relationship between Is1 and Is2, right? That relationship is relatively simple if you look at it. This current is Is1. It's current divided between these two. So Is2


[User] Please transcribe this text

[Assistant] Do you agree that IS2 is negative IS1 times this resistive divider, which is basically RS divided by RS plus RMV?


[User] Please transcribe this text

[Assistant] This calculation is a little bit, I mean, the algebra here just takes a few lines, so you have to bear with me, but we get to some meaningful results after.


[User] Please transcribe this text

[Assistant] Uhm, it's not that bad, but just, we'll have to just carry through. So, this is the IS1, so therefore, IS, which is IS1 plus IS2,


[User] Please transcribe this text

[Assistant] So we have this expression for IS. In terms of purely IS1.


[User] Please transcribe this text

[Assistant] So what is left to calculate, and if you know IS, you know your way out.


[User] Please transcribe this text

[Assistant] So the thing that's left to calculate is IS1 in terms of the IN. Right?


[User] Please transcribe this text

[Assistant] Cause then we can plug it in and you can have an expression for vout in terms of vin which would give us the game.


[User] Please transcribe this text

[Assistant] So nothing magical is happening. Some basic algebra.


[User] Please transcribe this text

[Assistant] It's, this voltage is dropping across this resistive combination.


[User] Please transcribe this text

[Assistant] So we need to just calculate, so we know that IS1


[User] Please transcribe this text

[Assistant] Is this voltage divided by this combination of resistors. So it's VN divided by what? RM plus RS parallel RMB.


[User] Please transcribe this text

[Assistant] So, I need to p- calculate this. So now I have to do a little bit of algebra, right? So as I just V in, need to simplify this. Generally, generally would like to keep this in this form.


[User] Please transcribe this text

[Assistant] These are, you know, the late Professor Middlebrook of Caltech.


[User] Please transcribe this text

[Assistant] Uh, he had an expression for these. He said, he used to call them low entropy forms of equations. There's high entropy form and low entropy form for equations. This is a low entropy form.


[User] Please transcribe this text

[Assistant] So whenever it has meaning and insight for us, we'll do that. Now, in this case, it happens that we need to kind of expand it because it's going to get multiplied by this thing and you will see it's going to simplify.


[User] Please transcribe this text

[Assistant] So we need to expand it to get that simplification, but in general we'd like to keep these low entropy forms.


[User] Please transcribe this text

[Assistant] So, anyway, so we'll do that, we'll go to the high entropy form.


[User] Please transcribe this text

[Assistant] The sum of the three way, the sum of the two way products. Of these things.


[User] Please transcribe this text

[Assistant] So gain, according to this, is going to be negative


[User] Please transcribe this text

[Assistant] Rd, and now we have this guy, these guys. So, I'll divide this denominator by rmb. So I can get rid of that guy. So what I'm gonna be left, what are we gonna be left with is gonna be rd divided by, so you get, here you get an rm, and what do you get here? You get rs, right?


[User] Please transcribe this text

[Assistant] But RM over RMB is something, it has a name.


[User] Please transcribe this text

[Assistant] The ratio of the strength of the transconductances of the two transistors. And we say it's like 0.2, 0.1, 0.3, depending on the transistor. So the back transistor is about 1 fifth to 1 tenth.


[User] Please transcribe this text

[Assistant] Weaker, or ten times weaker, or five times, five to ten times weaker. Which basically becomes RMB over RM.


[User] Please transcribe this text

[Assistant] No, no, sorry, the other way around. Heh. This is GMV over GM, and this is RM over RMV.


[User] Please transcribe this text

[Assistant] So gmb to gm is .1 or .2 and therefore rm to rmb, so rmb will be larger.


[User] Please transcribe this text

[Assistant] That's also chi, which basically makes this expression 1 plus chi. So, what has changed due to the body effect?


[User] Please transcribe this text

[Assistant] Let's, let's, so this is the expression for the gain with the body effect. That is the complete expression.


[User] Please transcribe this text

[Assistant] Now, what do we learn from this? Well, let's compare this with that.


[User] Please transcribe this text

[Assistant] I can rewrite this so that it looks even more similar to that. I can reorder them. Rm plus Rs.


[User] Please transcribe this text

[Assistant] What do we, what, when you compare this to that? So what is this new rule?


[User] Please transcribe this text

[Assistant] Says, the ratio of the total resistance in the drain to the...


[User] Please transcribe this text

[Assistant] Intrinsic resistance of the source plus the extrinsic scale by 1 plus chi.


[User] Please transcribe this text

[Assistant] Well, remember, the reason you have this thing is that you're really trying to lump the effect of two different transistors into one expression.


[User] Please transcribe this text

[Assistant] And it's a relatively simple expression to capture the effect of two transistors operating simultaneously.


[User] Please transcribe this text

[Assistant] So what it says is that really the explicit resistor that you put there gets scaled by 1 plus chi. Now if chi is .1, it's a 10% error. If chi is .2, it's a 20% error.


[User] Please transcribe this text

[Assistant] And you see this scaling happen a couple of times in a few of these expressions that we are going to derive. So,


[User] Please transcribe this text

[Assistant] Yeah, it's scaled, but still, it's the ratio of the total resistance in the drain to the total resistance in the source with one adjustment for the total explicit resistor.


[User] Please transcribe this text

[Assistant] So still that expression is quite useful. This is just like a correction to it.


[User] Please transcribe this text

[Assistant] Uh, but it allows you to calculate it, but other than that, it's fine. It's, it's, and it takes that effect into account. And of course, if you, your back gate is somehow connected so that you don't have the body effect, that kite disappears.


[User] Please transcribe this text

[Assistant] Because you don't have the G and the drive capability versus the, you know, the load, et cetera, et cetera.


[User] Please transcribe this text

[Assistant] And we will switch back and forth. Sometimes we write it in the other form. The form that


[User] Please transcribe this text

[Assistant] Textbooks generally write this, is this. They multiply everything by GM.


[User] Please transcribe this text

[Assistant] The numerator and denominator. So that would be the more familiar form if you have seen this before. It would look like GMRD.


[User] Please transcribe this text

[Assistant] But I think this interpretation is more conducive to design because it helps you pick values more clearly and directly if you're making a design.


[User] Please transcribe this text

[Assistant] You're just analyzing something, I guess it doesn't matter, any of them will give you the same number.


[User] Please transcribe this text

[Assistant] We've talked about these things, so let's briefly talk about it. What is the input resistance?


[User] Please transcribe this text

[Assistant] If I apply test voltage here, what is the current? Zero. So the ratio of the voltage to current is going to be


[User] Please transcribe this text

[Assistant] Infinity. So the imp- the low frequency input resistance of this classical model for MOSFET is infinity. So another way of saying is beta is infinity. Right? Because alpha is one. And beta is alpha divided by one minus alpha.


[User] Please transcribe this text

[Assistant] It's necessary and it's important to understand it because you will see when we try to make more sophisticated stages, it will have an impact. So this is a necessary calculation and we've done a good chunk of it already. Uhm, so it's not gonna be that hard. So for the output resistance, what is the process we use? We say you have the IS1


[User] Please transcribe this text

[Assistant] You use this thing, so you have this small signal model, but what's happening to the gate when you try to calculate the output resistance?


[User] Please transcribe this text

[Assistant] The way you calculate output resistance is that you null all the independent sources. You set them to zero. So your input voltage source is null, which basically means that this is shorted. Right? And then now we have to of course put the RO there. And then you have the other source for the


[User] Please transcribe this text

[Assistant] Well, so you have, so this is Rm, this is Rmb, this is Is2, Is2, and then this is basically, we are looking at the intrinsic output resistance, of course that would be in parallel with Rd.


[User] Please transcribe this text

[Assistant] So you're looking at what we see here, so we call it R out prime, and then whatever that is, the total R out,


[User] Please transcribe this text

[Assistant] Is going to be basically R out prime in parallel with RD. And then here you also have the RS.


[User] Please transcribe this text

[Assistant] So you're trying to calculate the resistance looking into here. In other words, you're applying a Vx.


[User] Please transcribe this text

[Assistant] So you're applying a vx, and you're measuring ix.


[User] Please transcribe this text

[Assistant] Circuit a little bit carefully, you will see something you can observe, you can make a few observations that can simplify.


[User] Please transcribe this text

[Assistant] So, I can basically take these, we can take these and bring them down here. So I can take this, detach, flip it down here. So I can put this guy here, RMB, IS2.


[User] Please transcribe this text

[Assistant] Okay, I can see, we can simplify it even more. We can say look, the combined current IS1 and IS2 of these two determines the combined current here.


[User] Please transcribe this text

[Assistant] So I can just lump all of them into IS. So you can say, I can get rid of one of these sources and say, look, this is just IS. Which is IS1, so this is IS. Which is IS1 plus IS2.


[User] Please transcribe this text

[Assistant] And that's the current going through the parallel combination of these two resistors anyway. Okay, so I can get rid of that too.


[User] Please transcribe this text

[Assistant] We agreed that this is still the same thing. So now it's starting to become easier, right? Think before you act. Always. Just, uh, that. Now,


[User] Please transcribe this text

[Assistant] Okay, so what is this current? Again, we had a similar argument with the BJT. This is an RM at most. It's an RM parallel RMB. So this parallel combination of these, all of these things is gonna be less than RM. This is an RO. So if the ratio of RO to RM is not large,


[User] Please transcribe this text

[Assistant] So if that ratio is large, we can say, well this is really dominated by Ro, so this current is approximately Vx over Ro. It's a large resistor in series with a smaller resistor.


[User] Please transcribe this text

[Assistant] So roughly that's what it is. And that basically sets, if that current is known, then this Is1, as a function of that, is going to be negative. So, so that's that. So Is1 is gonna be negative of Vx over Ro, which is the total current, current divided between these guys, which is gonna be Rs divided by Rs plus Rm parallel RmV. Okay? Basic calculations.


[User] Please transcribe this text

[Assistant] And that is what's gonna come off of here. So what you're gonna get, the total current Ix, is gonna be Is, uh, plus,


[User] Please transcribe this text

[Assistant] Vx over Ro. But Ix is given by this, so basically you can factor Vx over Ro, it will become 1 minus Rs over Rs plus Rm parallel Rmb, which is Vx over Ro.


[User] Please transcribe this text

[Assistant] So essentially we have our R out prime, which is ratio of Vx over Rx. So R out prime,


[User] Please transcribe this text

[Assistant] You're right, r out prime is gonna be, which is defined as vx over rix. From this is going to be


[User] Please transcribe this text

[Assistant] Do we agree? Did I make a mistake somewhere? No? Alright.


[User] Please transcribe this text

[Assistant] And that requires some simplification, so that's RO times, this is 1, plus this ratio, RS divided by RM over RMB. And now we can simplify it a little bit.


[User] Please transcribe this text

[Assistant] So what, how can we simplify? We can write R, let's write Rm, Rm, oh, parallel Rmb. Rmb is Rm.


[User] Please transcribe this text

[Assistant] Yes, Rm divided by, so this becomes 1 plus chi.


[User] Please transcribe this text

[Assistant] That's one plus GMRS one plus kind.


[User] Please transcribe this text

[Assistant] Again, you see that the effect of that extrinsic resistance in the source


[User] Please transcribe this text

[Assistant] Because of that back gate effect, is multiplied by 1, scaled by 1 plus chi.


[User] Please transcribe this text

[Assistant] So if your chi is .1 or .2, it will increase it by...


[User] Please transcribe this text

[Assistant] Point one or point two. So it's not necessarily a bad thing.


[User] Please transcribe this text

[Assistant] This is not necessarily a bad thing because your upward resistance is now becoming a little bit larger. Again,


[User] Please transcribe this text

[Assistant] You have to differentiate between, this is really a second order of fact. Like a 10% thing. Right?


[User] Please transcribe this text

[Assistant] If, if something is ten, in tens, cup, few tens of, low tens of percent, that's second order. If it's in hundreds of percent, like few hundreds, it's first order. And if it's, uh, in few percents, it's second order, eh, third, you know, third order really. So, at least for us, in this context.


[User] Please transcribe this text

[Assistant] Again, scaled by 1 plus rs over rm, but factor of, so basically it's scaled by the same factor that your gain is reduced. You can see it from either one of those equations.