What's up, everybody? Jay's here for Jasper's case breaks.com. We just sold out 2023 Panini daughters for the hobby Three bucks break number nine chasing some CJ Strau baby. So here we go guys to my knowledge No downtown or great iron marvels or unleashed have been hit. So trying to get some of these little Case hits here guys. So again, it was between Ethan and Nick Stover So I'm gonna double up the names guys and you guys will get two red teams each per spot three and a one four times one two three four Four times three and a one four four Nick down a Nick and then four times one two three four Saints down the lines All right Stover. So basically You don't have the Patriots and the Steelers But you basically have everything else Nice made it work. All right. So here we go One two three four stacks here. I roll a five or six. We'll just re-roll it again three And do that stack right there We'll move these over here Oh Justin Fields John and mingo red Nick Bolton the champ is here chiefs When a Stover to on HN Ziek Jerron Hall JJ Chase Brown to 50 Buddha Baker. No name pushing him dollars Bees on Porta Anthony Richardson Aiden O'Connell and a Keanu Benton 75 and out of 25 cam Smith Little optic preview there when James to 399 Michael mayor, huh? Second box price young will Anderson jr And it's a J Spears red Because there is Tony numbers game for the Giants When a Stover, it's kind of cool on say Smith You didn't Hutchinson Johnson and Anthony Richardson very nice Colts gonna Stover We got broader Jones to 77 and at a 50 Joy Porter, Jr. A lot of 50 nice one there for the Steelers when I eat them war moon 200 for the Titans going Stover and Travis Kelsey to 399 Anthony Richardson bomb squad Herbert die cut to 75 Devon HN and Dodson Ben Scoronic Evan Ingram Kendrick Miller, all right Down to the final box guys Josh Jacobs to 28 well That was Aaron Rodgers autograph for a second He was actually redemption so Delpit Jerry Hughes Larry Johnson Nice autograph there for the uh chiefs Season pass. I think it is or no This is a season pass I think so That's going to go to the Kansas City Chiefs in Stover You get an opanel Then we got Jack Campbell to 25 Jaylin Carter and Dwayne McBride to 50 Vikings from Stover and Jerry Rice for the 49ers Relic Jake Heiner All right some cool stuff, but again still no case it We got Half a case remaining guys nine boxes. So at least three more breaks I'll repost it up if I haven't already. I don't know if I did or not I want to do another one guys Getting closer and closer. Appreciate it. Jaspy's case breaks.com guys some really nice stuff here So do a quick recap Larry Johnson autograph Nick Bolton Tony Richardson there and a lot of nice cool inserting colors though.  Thank you


Configurations of electric charge require energy to be assembled, but once assembled, they can store that energy through the potential energy present in their configuration, due to the mutual forces they exert on one another through their electric fields. Let's take a look at a workhorse of common electric circuitry, the capacitor, which is nothing more than a configuration of charge that can store energy, or if disassembled, release energy. The topic that I'm going to cover today regards the first major electrical device that we're going to encounter, the capacitor, and it combines all of the elements that we've talked about so far in the class. There will be electric fields, there will be charges separated by a distance, there will be electric potential differences, and therefore potential energy available in this device, but before we get going I want to cover something which is also going to be present in this lecture as we move forward, and that is the battery. The battery is the major workhorse of circuit discussions, and by circuit what I mean is the following. If I can zoom in here for your convenience, it's convenient at this point to discuss the very basic idea of a circuit. Now we haven't quite talked about the movement of electric charge yet, we're going to get to that in detail shortly, but suffice to say that a circuit is basically a device constructed out of conductive material, so for instance here I've made a very simple loop, and it's made from a conductor, that is it offers essentially no resistance to the motion of electric charge, so no resistance to the movement or motion of charge, Q. That's the definition of a conductor, and that's in contrast with an insulator. An insulator is a material that doesn't let charge move around at all or very much. Circuits will be made from conductive material, and you can think of them as pipes, and if we imagine the copper or aluminum wires that usually make up a typical circuit as pipes that can carry electric charge, what we're going to be interested in knowing is what direction is positive charge plus Q flowing in the circuit. So as we build up our toolkit for understanding electric circuits, the first essential piece is merely the conductor. The conductor is the piping that allows us to hook up different components and allow charge to move freely between the components. Now having pipes by themselves is not particularly useful. If you think of electricity and the flow of electrons or the flow of positive charge in analogy to the movement of water through pipes, you need to have something that's capable of pumping the electricity through this conductor. On its own, if you just put charge in the conductor, it's not going to go anywhere. The conductor is electrically neutral because most matter that we encounter in everyday life is electrically neutral. There are equal numbers of electrons and protons in the material. And so you've got to entice the electrons to move in one direction and thus cause the positive charge to move in the other. So it's important to remember if we sketch a little picture of an atom, and out here in orbit around the central nucleus of the atom is an electron, we have to remember that when we are talking about electric charge moving in a circuit, the majority of the time what's actually moving is the electron. That is we're ripping it off of its parent atom and then moving it through the conductor. But because of the convention that when we talk about the motion of positive charge in a circuit, that's really what we mean by the motion of charge. Thank you Ben Franklin. We have to keep in mind that if the electrons go to the right, it means that positive charge is flowing in the opposite direction, that is to the left. So in a circuit, we're not so much interested in the direction that the electrons are moving, although they are the things that are typically actually moving in the circuit. We're actually interested in the direction opposite the way the electrons are moving. That's the direction that positive charge is flowing in the circuit. We need a pump. We need something that's going to entice these electrons to move in one direction and thus have the positive charge move in the opposite direction. And that is where we hit the concept of the battery. Now the battery can be drawn into a circuit diagram like the one I just showed you by putting a series of parallel lines, one big, one small, one big, one small, and then imagining a little line of conductor that comes out of each end of this little device. And then over here I have some components that go into the circuit. This is the battery and this is the pump. This is the thing that allows us to move charge. And honestly, if that's all you remember about a battery, you're already in pretty good shape, although we're going to drill down into this a little bit more deeply. Now it's convention to draw a positive sign on one end of the battery, and that happens to be the one where you have this longer terminal touching the conductor. So that's going to be the top side of the battery as I've drawn it here. And this implies by convention that the negative side is the other side of the battery. And the reason to do this is that when you draw the symbol this way, you immediately know that the flow of positive charge in the circuit is going to be out of the positive side through whatever the components are in the circuit and then back into the negative side over here. So that's why this symbol has this convention. The symbol for the battery tells you a lot once you write it down or once you see it in a circuit diagram. It tells you that this battery right here is trying to push positive charge up and around clockwise in this circuit. Now a battery is nothing more than an electric potential difference. So it contains some delta V. And if we imagine for a second this battery symbol, so here I'll draw it again, with its plus side and its minus side. Well if it's true that positive charge is moving this way through the battery, it must be true that the electric field inside the battery correspondingly points in this direction. I mean after all positive charge wants to follow the direction of the electric field lines in the way that they point. The electrons in the battery of course are going in the other direction. So if we wanted to imagine the actual things that are moving inside of these circuits, the electrons, we have to think of them as going down, not up. Now this is just the fact that we're stuck with this convention, that we think about the way the positive charge moves in circuits. And again you can thank Ben Franklin for the beginning of this convention. Alright well, so positive charge is moving up through the battery like this, being pushed through the battery, pumped like water through the circuit. This implies that the electric field in the battery must point in the same direction that the positive charge is moving. And so it must also be true that we have a situation where the initial and final electric potentials that are felt by the positive charge are in a sequence such that v-final is less than v-initial. And that is that the change in the electric potential must be less than zero because the change in the electric potential, which is v-final minus v-initial, would give you a number that's smaller than zero. So these are just some basic things that you want to keep in mind. Positive charge is going to move up through the battery from the negative terminal to the positive terminal. That's the word that's used to describe each end of the battery. And you're often used to seeing batteries that look something like this. They have a little copper top on them.  This is the positive side. This is the negative side. And so if we imagine that this is a double-lay battery, this has an electric potential difference between the two sides of the battery that's equal to 1.5 volts. That is the high potential side is at 1.5 volts, and the low potential side is at zero, as an example. Now there's one more essential thing that I want to note about this very simple little electric circuit that we've drawn here with our battery, with its positive terminal and its negative terminal. Let me redraw this one more time. Okay, so here we have a bunch of components in the circuit and we'll get into exactly what those are very shortly. We're going to visit our first component of an electric circuit in a moment. If we were to measure with some device the electric potential across this battery, we could do this, for instance, by hooking up a voltmeter, something that's actually capable of measuring an electric potential difference, to one side of the battery and the other. And that might have some kind of little gauge on it that indicates what the voltage is across the battery. Well, if we were to make a measurement, let's say that this is a AA battery, so it has a 1.5 volt potential difference across its terminals. If I were to put the voltmeter here and here, right on the top and bottom of the battery, and ask it, what is the potential difference? It would tell me 1.5 volts. Now imagine if I were to move the probes of the voltmeter down the conductor and then ask again, if we call this point A and this point B, this is the voltage at point A, and then we were to ask the question, what is the electric potential difference if I put the voltmeter 1 probet point B here and 1 probet point B here? Well, what I've done is I put a whole length of conductor in between me and the end of the battery on this side and another whole length of conductor in between me and the whole battery on this side. There are no other batteries in the way, and so the only potential difference that is being probed is still the potential difference between the battery terminals. There's no other change in electric potential as we move through this conductor and place our probe a little further down the line here and here. And so it must be true that the electric potential difference is still 1.5 volts. After all, we've encountered no other device that has an electric field than it besides the battery. And I can repeat this exercise and pick more points C and C and keep asking this question, what's the potential difference between this point and this point which really is just a bunch of conductor attached to the ends of the batteries? And I'll keep getting the same answer. Now it could be that there's some complicated mess of components inside here and inside of that we may experience a whole bunch of changes of electric potential. But because electric potential is just work per unit charge in a circuit, if work per unit charge is conserved because there are no external forces acting on the circuit, then it must also be true the potential difference is conserved. And so even if I were to stick the probes here at these points right on the edge of the components, I should still find that the potential difference across the components is 1.5 volts. So what's really great about this is because energy is conserved, I know that if this is my only battery that I'm considering and I've hidden all of my other components inside this blob and we'll explore what might be in here in a moment, I know that the electric potential difference across this blob is the same as the electric potential difference across the battery because all that's in my path is a whole bunch of conductor that doesn't impede the flow of electric charge. In and of itself it doesn't provide any more additional electric potentials that have to be crossed by charges as they move through the wire, for instance. And so if you're asked what's the electric potential difference across the components of the circuit in this picture, the answer is, well, it's just the electric potential difference across the battery, whatever that is. And so this will come in handy when we start thinking about capacitors in just a moment. So let's begin to think about capacitors and I'm going to pick up here where I left off at the end of my last actual in-person lecture. What we were doing at the end of my last in-person lecture was we were considering a very special situation. Imagine that I have a disc with area A equals pi times its radius squared. All right, so here's the radial line of that disc, some circular disc and I'm considering the electric field strength at some point P above the disc along this axis that goes through the center of the disc. Well, what we found out was as this distance above the center of the disc, which we can label as Z, as Z gets to be much, much less than R, that is, as Z gets very close to the center of the disc, we find something quite interesting happens to the electric field. The electric field is given merely by the surface charge density on the disc divided by 2 epsilon naught, where epsilon naught is a constant of nature. Epsilon naught is related to K by this formula here. Epsilon naught is 1 over 4 pi K, so if you know K, you can calculate epsilon naught. And the only thing left here is the direction in which the electric field points and if we imagine here that we have some positive charge Q spread out over this area A, then the electric field we expect to just point up toward the point P and we would expect in this case that it just points in some direction, for instance K hat straight up away from the disc. And what's really neat about this particular situation where you're very close to the surface of the disc, far closer than the radial width of the disc itself, you find that there's absolutely no dependence on Z in this formula. You can keep moving around very close to the disc and the electric field will always have the same strength, sigma over 2 epsilon naught, where again sigma is just the surface charge density, it's the charge divided by the area, which for a disc in this case is pi R squared. And this is a really neat result because we've just learned something really interesting about a disc of charge when we're very close to the surface of the disc. This gives us a uniform electric field, one that does not change with position. Unlike the point charge or the dipole field, which do change in some cases quite rapidly with your distance from the charges themselves, in this particular special situation where you're very close to the surface of a disc of charge, you actually find that the electric field is essentially uniform just above the disc. It isn't really changing at all with your distance from the disc. Now eventually you go far enough and that won't be true anymore. So we have to consider this limiting case. But what's great about this is, you know, it's essentially very straightforward in the lab environment or in an engineering environment to create a disc that's filled with a whole bunch of charge. You know, you could imagine making a disc out of some insulating material and through some means depositing a net charge on it. And the great thing about doing that is now right above the surface of the disc, you've engineered a situation where you have a uniform electric field whose magnitude is given by a very simple equation, the surface charge density divided by 2 epsilon naught. And this is why this is so powerful. Because what happens if we put two of these discs next to each other, one with a charge plus q and one with a charge minus q? So let's explore that possibility. So my picture will now be that I have a disc up here with a charge minus q. And then below it I put a disc with a charge plus q. And these discs are separated by some small distance d. And they both have radii r. So if I view this from the side, I can imagine that the sides of the discs look like this and I'm exaggerating the dimensions of this a little bit. The separation between them is d. We have plus q down here and exactly opposite amount, opposite sign but equal magnitude charge up on the top disc, negative q. They both have the same areas, a and a, which would just be given by pi r squared for the discs. And so we can think about what's going on inside of these plates, inside of these two discs. Well, we already have half the answer. We know that there's an electric field due to the positive charge from the lower disc. We can draw this by just a bunch of vertical arrows with equal spacing coming up from the bottom of the disc. We're using this approximation that if this distance here d is a whole lot smaller than the radius of the discs, then we essentially have a uniform electric field most everywhere inside of the space between the discs. Now if we consider the same situation for the top disc, well, we also there have an electric field, but rather than pointing out from the disc, it points in toward the disc. And again, for the same reasons that the lower disc's electric field was uniform, the upper disc's electric field should also be uniform very close to the surface of the disc. Well, now we can very easily calculate what the total electric field is inside of this space here between the two plates, the two discs. It's just going to be the electric field due to the positively charged disc plus the electric field due to the negatively charged disc. And we can very quickly write down what this is going to be. We know that this is sigma over 2 epsilon naught k hat. And this will also be sigma over 2 epsilon naught k hat. And so we find out is just the total electric field is sigma over epsilon naught k hat. And that's it. And the reason that this is remarkable is we can engineer in a very straightforward way a situation where we have a device with separated charge plus q and minus q, a small distance between the charges and in between them a uniform electric field. And what's great about uniform electric fields is it's really easy to do calculations with them. So let's do some calculations with them. And in particular, let's think about what it would take to move a little test charge, q zero, from the lower plate to the upper plate. So let me exaggerate this distance a little bit here. So here's the negative q and the positive q. And let's imagine this is my little q naught and it's going to take a journey. I'm going to move it straight across this gap and have it end up here. So this is its initial position. This is its final position up here. The electric field inside of the plates is uniform and points vertically upward from the positive plate to the negative plate. So there's our e vector and we already know what that looks like. E vector is sigma over epsilon naught k hat. And I'm going to grab this little test charge q naught and I'm going to move it across the gap. Now we know from the discussion of work that I don't just have to grab it and move it straight across the gap. I could grab it, whirl it down here, bring it back up and then eventually drop it on this point right across the gap that I've indicated here. Or I could take it on another path. I could move over here and then kind of zigzag back and forth and then eventually, boom, land on the top plate. But I know from energy conservation that it doesn't really matter which path I take. All that matters is the separation between the initial and final points. And that is what's going to define the work that's required for me to move this charge. So let's think about work. The work done by me, so the applied force in this situation, not the field, the work done by me, is going to be equal to the negative of the work done by the field in moving this charge across the gap. Okay, well, no problem. We can figure out what that's going to be. We know that, of course, the electric field would like to move the charge across this potential gap here. That's the direction that the field would love that charge to move.  Well, where are we going with all of this? We can relate the applied force. It's the negative of the work done by the field and that's equal to the negative of the change in potential energy, which is just the change in potential energy. Well, we can find the work done by the field moving this charge across the gap. That's not so bad. The work done by the field is just going to be equal to the integral of the electric field dotted into little pieces of the path as we take our journey across the gap. That's the definition of the work done by the field in this case. It will be the integral of the force exerted by the field on the little test charge dq dotted into the little pieces of the path, ds vector, as we move across the gap. Well, let's think about our path. We're starting at some initial point i and ending at some final point f. We know that the electric field points straight across from i to f and if we imagine taking the simplest possible path, s vector, this could be made of a whole bunch of little ds vectors. Well, you can right away see that if e points in the k hat direction, ds vector can be simply written as k hat ds, where ds is just the magnitude of the step that you take in the k hat direction each time. And since the force exerted by the electric field is just going to be given by the charge, the test charge, times the electric field at each point. And because that electric field doesn't change at all for every step we take in the trip, we have a fairly simple integral to do here. We just wind up with q naught, the integral of e ds, and that's it. Since e is equal to sigma over epsilon naught k hat and ds vector is equal to k hat ds, the dot product of these two things is just going to be equal to sigma over epsilon naught ds k hat dot k hat, and the dot product of a unit vector with itself is always 1. So in the end we get a pretty straightforward integral that we have to do here. We're just going to get q naught, sigma over epsilon naught, those are just constants, integral of ds, and that integral is going to go from our initial position 0 to our final position, which is d, the distance across the gap. And so at the end of the day we're left with a pretty straightforward answer. The work done by the field moving a little test charge across the gap is just going to be equal to q naught, sigma over epsilon naught times d, and that's it. Well, this is nice and all, but the problem is that of course this work depends on the sign of the charge that we're moving, in this case it was a positive charge, and it's annoying to have to keep carrying this charge around. We don't want to have to keep doing that. And so that's why it's very important to calculate the work done by the field per unit charge, which is just equal to sigma over epsilon naught d. And hopefully we recognize this by now. The work per unit charge done in moving the electric charges across the gap is just going to be equal to the negative of the change in electric potential. And here we have a really important relationship. Now let's have a look at delta v. As a reminder, delta v is equal to the final potential minus the initial potential. And because we're talking about a positive test charge moving in the same direction as the electric field in this particular example, we're talking about going from a point of high electric potential to a point of low electric potential. So if this is the initial potential and this is the final, the final will be less than the initial. So we can decide where we're going to set the zero of electric potential, for instance in our system in this picture. And it's probably convenient to choose this one to be zero because it is the final position that we wind up at, and it's supposed to be the lowest potential point in the system. We have crossed the gap. We're on the other side of the electric field. That ends the electric field. And so that should also be the point where we reach our lowest electric potential. So let's call that zero. So then we have that delta v is equal to zero minus whatever the potential was on the other side, which we'll just call v. So we'll call the initial potential v. All right, well this is great because we see that the work done by the field per unit charge is equal to sigma over epsilon naught d, which is equal to the negative of the change in potential, which is equal to just v. Because I have a minus sign here and a minus sign here and so I get a positive sign. We can very quickly write a relationship between the electric potential on one side of the system, the charge density stored on the surfaces of either of the plates and the spacing between the plates. And if we go ahead and actually write out the charge density as q over a, and then we have one over epsilon naught and d, we have this relationship here. And so we arrive at the very first piece of electric component in a circuit that we can actually start to think about and analyze and see what it's going to do. And that is this device, which is called a capacitor. And a capacitor is nothing more than a set of plates where you can store charge and you have the same magnitude charge on either side of a gap. So here you have a gap. So far we have had a gap filled with absolutely nothing. That is not even air, just empty space or vacuum. On one side of the gap, we have a positive charge plus q. On the other side of the gap, we have a negative charge minus q. Each of these plates has the same area A and they're separated by a distance d. And this is the archetype for the capacitor. So capacitors are distinguished by the fact that the amount of charge that you are able to put on the either plate of the capacitor is proportional to the potential difference across the plates. And the relationship is given merely by a constant c, which is known as the capacitance of this device. Capacitance has units. And you can very quickly figure out what they are. The units of capacitance are coulombs per volt. And this is known as the ferrad, which is just going to be coulombs divided by volts. Remember volts are the amount of potential energy per unit charge.  That's in honor of Michael Ferraday, one of the great physicists of the 1800s who is considered one of the people that really firmed up our understanding of the electric force and later the magnetic force. So armed with this definition, that for a capacitor there is this relationship between q and v, we can go back to our parallel plates with area a and separation d, and we can very quickly tease out what the relationship is between q and v. Specifically, we can figure out what the capacitance is for a parallel plate system like the one we've been looking at. Well, we have this equation, that v is equal to the charge divided by the area, one over epsilon naught and d. And all we have to do is move a bunch of these numbers over to the other side of the equation and solve for q. And what we find is that q is equal to a over d, epsilon naught, and that is multiplied by v. This is a very special case. This is for the parallel plate system, and this is known as a parallel plate capacitor. And so we can very quickly write down the capacitance for the parallel plate capacitor. It's just a over d epsilon naught. And we learn something relatively neat from this. If you can construct a system of parallel plates and you can put plus q on one of them and minus q on the other by some means, thus creating an electric field in between the plates and a potential difference between the plates as a result, you can control the exact details of the relationship between the amount of charge on the plates and the potential difference across the plates simply by adjusting the properties of the plates. You could increase their area. That would make the capacitance go up. You could increase the separation. That would make the capacitance go down. You could decrease the separation and make it go up. Epsilon naught is a very special constant of nature. And you can think about it as telling you about the permeability of empty space to electric fields. If we were to find a way to alter that permeability, we also could increase the capacitance. And it turns out that epsilon naught takes its smallest value, the smallest permeability of the vacuum that you can get is when you just have empty space. That is absolutely nothing there at all. We can actually change the properties of the gap in here. We can change the material inside this gap. And in doing so, we can also alter the properties of the capacitor. We can alter the capacitance of the parallel plate system. We'll explore that a little bit in a moment. So what I'd like to do now is actually use a simulator based on real observed properties of parallel plate capacitors and show you some of the behavior of a capacitor when we hook it up to a battery. And we can use the battery to create a potential difference to move charge from one side of the capacitor plate system to the other and create this charge imbalance. So let's take a look at that using a simulation. Now it's one thing to sketch on a little tablet computer equations. It's another thing to demonstrate using a simulation of the process. And so what I'm going to do now is walk you through a demonstration of a parallel plate capacitor in a circuit connected to a battery. We see from the sketches I was making earlier that we have the essential components here. We have a battery that is a source of electric potential difference that we can use to move charge in a circuit. We have conductors, these gray wires that stick out of each end of the battery from the top and now on the bottom down here. And then we have an arrangement of parallel plates. We have a rectangular plate up here on the top. We have a rectangular plate down here on the bottom. Well, okay, it's actually square but it's tilted at an angle so it looks a little rectangular. And we have the ability to do things. We have the ability to grab the plate and stretch it and make its area bigger. We have the ability to move the plates closer together or further apart from one another. And so you can already kind of see that this is a nice little laboratory for playing around with capacitance having built up some language from mathematics about what capacitance is and how it relates to the area and separation and the material in between the parallel plates. So one of the things that I can do just quickly to demonstrate what happens in a circuit is to actually take this battery and switch it on. So you see the battery comes with a little switch here and we can put on this battery. We can crank this thing up to a one and a half volt potential difference, 1.5 volts. And so, again, the convention is that the plus side is the copper top in the way that this is drawn here. The minus side of the battery is the other side below the copper top down here. And the plus side is supposed to be the part of the battery where positive charge is emitted from, so we would expect positive charge to come up here and then get on this plate and accumulate on this plate. And the bottom of the battery is the source of negative charge. Negative charges would move in the other direction and they would accumulate on this plate. So let's think physically about what's going on. In order to charge up the capacitor, I have to begin in a situation where the capacitor actually has no net charge stored on it. And in this case, I've essentially switched off the battery. Its voltage is set to zero. So there's absolutely no electric field anywhere in the system and there's no way that charges can be induced to move anywhere in the system. Well, we have plates. Let's imagine that they're made of something like copper. Copper is a conductor. What does that mean? Well, it means that its outermost electrons are very loosely held by the rest of the atom. And so if we could put a large enough electric field across a copper atom, we could induce those outermost electrons to leave the safe, comfortable orbit of their parent atom and move and go someplace else, end up someplace else inside of the material. And that's exactly what the battery lets us do. It lets us create an electric potential difference over here inside the battery, which sets up an electric field. That electric field can be set up to point up and by doing that, we can induce electrons to move off of the parent copper atoms. Alright, well, no, fine. So we are going to have an electric field that points up and this is going to cause a force on electrons. So let's imagine we're electrons up in this plate. There's an electric field here that points up into the top of the battery and it is established through the whole copper. There's no other source of electric field anywhere else to add or subtract from it. So whatever the electric field is at the top of the battery, it's just going to persist all the way over here into the top of the capacitor, the top plate. So the electrons in here are going to feel an electric field and they're going to want to move against it. So the electrons are going to start to move through this wire, down through the battery, out the bottom side, and then over here to the other plate. Now the key to a capacitor is that there's no way to jump the gap. This is a space that can't be crossed by the electrons. They simply don't have enough kinetic energy to get out of the material itself. So they can go through the wires. That's not a problem because wires are made of conductor. They're a nice free, essentially resistance-less path to the motion of electric charge. We have the battery. They can certainly move through that because that's where the electric field is. That's the source of the electric field. And then they can come out the bottom of the battery and they can get over to this plate and boom, you know, if they get here, they stop. And so we expect that as we crank up the voltage just a little bit. Do that again, not jitter so much. We'll begin to move a few electrons onto this plate and deplete them from this plate, leaving a net positive charge behind. So of course the convention is we're supposed to think about the way that positive charge is moving in the system. And here positive charge will be moving up out of the top of the battery and deposited here on the top plate. And that's exactly what we see. Now of course what's really going on is that electrons are being stripped from their parent atoms. They're going this way and they're piling up down here on this plate. And that's exactly what we see down here. And as we continue to crank up this potential difference in the battery, maybe taking it to about half full strength, we see that we can put more charge on the capacitor. Now what's going on inside the capacitor? Well, you can see here we also have an electric field. Here we have an electric field that points from the top plate to the bottom plate, from the positive charge plate to the negative charge plate. And charge will continue to move from one plate to the other. Electrons for instance will continue to go from the top plate to the bottom plate until the potential difference between the plates matches that of the battery. And charge motion will simply stop because now there's no more net potential difference in the system. So when thinking about a circuit, it's important to think about the electric potential difference induced by the battery setting electric potential difference induced on the capacitor. Those should be the same if you wait long enough because if you wait long enough enough charge electrons, for instance, will move from the top plate to the bottom plate until you get an electric field in here that exactly opposes the electric field in the battery and now there's no more net movement in the system. Okay, let's see what happens to capacitance. So I'm going to crank this battery all the way up to one and a half volts and I'm going to put a little meter on here that is a measurement of the capacitance of the parallel plate system. Now you could go ahead and calculate this yourself. You could use the known value of epsilon naught which is a constant of nature. You could multiply it by the area of the plates which for this setting is 158.1 millimeters squared. Be sure to convert your millimeters to meters correctly. And then the separation is 7.4 millimeters and again if you want to put this in meters at the end make sure you convert that correctly. From all of these numbers you can calculate the capacitance and the computer's done that for us. It's told us that for this configuration the capacitance is 0.19 times 10 to the minus 12 farad or about 0.2 picofarad. Now we can ask the question what will happen if I increase the area of the plates? Now remember the potential difference across the battery is 1.5 volts and at this point no more charge is moving. The potential difference across the parallel plate capacitor is also 1.5 volts and that isn't going to change. No matter what I do to this system I'm not going to change the electric field inside of this. I'm not going to change the potential difference across this. But what I can do, of course is I can change the capacitance and I can store more charge for the same potential. So if I increase the area I increase C, we expect that from the capacitance equation for a parallel plate capacitor and as I increase C for the same voltage charge on the same capacitor and that's in a sense where the term capacitance comes from. If I increase the capacitance of a capacitor I'm increasing its ability to carry that is its capacity for charge. I can shrink the area and I would expect the capacitance to drop and that's exactly what we see. Let me move this out to sort of an intermediate area again. Now what will happen if I decrease the distance between these plates? What happens to the capacitance if I keep the area fixed? I have the same potential difference across the capacitor. That's independent of the capacitance and I just move the separation to a smaller number. I shrink the distance between the plates. What should happen to the capacitance? If you said the capacitance should increase well let's go ahead and investigate and find out. So if I move this here the capacitance increases and the ability to hold more charge correspondingly increases. If I increase the separation I decrease the capacitance and I decrease the capacity with which the parallel plate capacitor can hold charge. So this demonstration is a very nice way to play around with capacitors and what I'd like to do now is show you what happens when you change the material inside the capacitor. Now on this tab of the demonstration lab I have the ability to take my parallel plate capacitor and shove a material into the space between the plates. Now this is not a conducting material it's a material that allows electric fields to move through it although it weakens them as they do. It does not allow charge however to move through it.  Air actually works pretty well you could use styrofoam, polystyrene, plastics things that don't let charge move freely but which can still allow for the passage of an electric field although as the electric field passes through the material it's weakened by the presence of the little dipoles that line up along the electric field. Now there's this thing called dielectric constant and all you have to do to use the dielectric constant is take epsilon zero and multiply it by the dielectric constant. Now I said earlier that epsilon zero that's the smallest value you can ever set that number to because it's the one that tells you basically the way that the vacuum of space, empty space allows electric fields to propagate through it. Any material put in the place of the vacuum will always increase the value of epsilon not to something else called epsilon and the way you get from epsilon not to epsilon is you multiply by the dielectric constant. So if I wanted to increase this value with which the electric fields are permitted to move through space all I have to do is dial up or down my dielectric constant and I can do that over here on the right.  Right now this configuration has a capacitance of about 0.4 picofarad and what I can do is I can alter the capacitance by grabbing this material and shoving it inside of the capacitor. I'm going to put it all the way in here and when I'm done you see that this material this capacitor is now capable of holding a whole lot more charge than it did before. Watch. Take it out, shove the material in and that's because I've taken epsilon not and I've multiplied it by a number greater than one called Kappa the dielectric constant. Here it's almost a factor of 3 bigger than 4 and that means this thing can hold 3 times more charge when I put this material inside of it. This is how you dial up capacitors to make stronger ones. You don't just have to keep increasing the area of the capacitor plates or the separation between them you could alter the material inside as well instead of having vacuum or air in there you could put in plastic or something like that and you'll see here that there's a number of different materials that we can play with so for instance glass is a very familiar material to most people and you can use it, it's an insulator you can stick it inside of a capacitor it has a whopping great dielectric constant of 4.7 and this really makes for beautiful capacitors. You can hold a whole lot more charge for the same electric potential if you shove glass inside of a parallel plate capacitor. So I hope that this has nicely demonstrated the ideas about capacitance and capacitors and there's one more thing we're going to do with these before we go into lectures on how to use capacitors in a circuit and then more about the detail of how electric charge moves inside of a circuit. We've gone through all this effort to engineer a really nice capacitor and that's great but one of the things we really care about as physicists is we care about the amount of energy that this device is now capable of storing for us in the form of charge separated by a distance and thus having an electric field between it that configuration allows us to store energy anytime we can separate charges and keep them apart we can store energy in the form of potential energy and then hopefully release it later by some other means. So the energy stored in our capacitor is something that we want to calculate and to do that we want to think about our little parallel plate system. So let us imagine that we have no charge originally stored on this device so it's capable of being hooked up to a battery but we've interrupted the circuit with something called a switch now you've heard about switches before you use them to turn on light bulbs all the time a switch is just a device that interrupts the flow of electric charge in a circuit and because this switch is open it's impossible for charge to be moved by the electric field in the battery because there is no electric field path that takes the electric field over to this side of the capacitor but of course if I close the switch I will be able to so I can indicate that here if I were to throw the switch and close it so that I create one nice path for this electric field to travel on from the battery I could begin to move electrons from the left plate over to the right plate and thus cause a positive charge to pile up over here and a negative charge to pile up over here and because I have some potential from the battery I expect, given enough time that the same potential difference will occur between my plates and the movement of charge will simply stop because there is no more net electric field inside of the circuit but we want to know now how much energy we have managed to store by moving all this charge and separating it and keeping it apart so that there's this electric field between the separated chunks of charge so we want to know the energy that was now put into the capacitor by moving this charge through the battery and to do this we can simply think about what it would mean to take a little charge maybe a little test charge Q naught and move it through this potential difference in the battery all the way over here and drop it on the positive plate so we're going to take a little positive test charge and we're going to move it through the circuit and deposit it on the other plate alright well in that case we know some of the relationships that are involved here we know that the relationship between capacitance and voltage across the capacitor is Q equals CV and we'll just leave C as a constant now we won't particularly stick in the parallel plate capacitor value here but we can later if we want to what we know is that every time we take a little bit of charge and we move it across the capacitor and we're going to correspondingly create a little V prime across the capacitor so the first charge we move maybe this is the first test charge moved by the battery across to the other side of the capacitor this is going to result in some new potential difference between the plates V prime it's not at the full strength of the battery yet but it will eventually get there given enough time so we know that our initial voltage across the capacitor given enough time, the final voltage across the capacitor will be whatever the voltage across the battery is that's our end point of this exercise and we've only started by moving an additional little bit of charge well imagine now that I move a little bit more so what I'm going to do is I'm going to increase the amount of charge that I moved by some DQ naught so I'm going to take another little bit of charge and I'm going to move it in the next step over here well in this case we actually have the capability of using calculus now to figure out the answer to the question what in the end will be the total energy stored in the electric field of the capacitor to get the total energy we want to figure out the total work done by the battery moving these charges across the plates so eventually we're going to want to get at the work applied by the battery to figure out about this problem incrementally in a calculus way we can already see that this is going to be equal to all the little bits of work that are needed to move the charges from one plate all the way to the other plate and so it's going to start off taking no work of course to move the first charge and in the end we're going to get to some final amount of work that will have taken to move all of the charges across this circuit alright well let's continue with this a little bit the little bits of work done by the battery are just going to be equal to the little voltage that's set up when we move each little bit of charge dq0 and now we have the ability to substitute in for this in terms of something that has voltage in it we can just use the capacitor equation dq0 is going to be equal to c dv' and that just comes from this capacitor equation up here so thinking about moving an additional little bit of charge dq0 across the circuit and to the other side of the capacitor so if we plug that now into the little bit of work that we are doing every time we move a little bit of charge we wind up with a very convenient equation here which is just cv' dv' and finally what we can do is we can integrate this so we can integrate the little bits of work applied from 0 up to the total and that's going to give us the total work done by the battery and that's going to be equal to the integral from 0 voltage up to the final voltage of the battery cv' dv' c is just a constant it's a constant of the geometry of the system area, separation of the plates material in between the plates that's it and so it won't participate in the integral at all and all we have to do is integrate dv' so this is just the integral of x dx which is not a bad integral to have to do and what we find if we work through this is that in the end the total energy that it takes for the battery to move all that charge from the one side of the capacitor system is given by one half times c times the voltage of the battery squared and remember the voltage of the battery squared is also going to be the final voltage across the capacitor plates so given that information we can do all kinds of things we can figure out what the energy stored in the field is we can figure out if we were to release that energy into kinetic energy how much kinetic energy you would get out of releasing the capacitor's stored energy from its electric field you can figure out the differences in potential energy you can do all kinds of stuff with this because energy is going to be conserved in the system and all you have to do is change it from one form into another you can change it from the potential energy stored in the field to kinetic energy of the motion of charges in the system so what I like to close with here right at the very end is just an example of where we find capacitors in the world around us and on the exam you saw a picture very similar to this you have the cell membrane there are different concentrations of ions inside and outside the cell membrane so for instance inside of here you have proteins which are anions and they can bond to for instance they carry a net negative charge they can bond to sodium and potassium ions there are pumps inside the cell membrane that can move ions from one side to the other and what we find is that the cell maintains an electric potential difference such that it's more negative in the intracellular part of the cell and so we have a separation of charge with a gap and that gap is the thickness of the cell membrane which is approximately 8 nanometers or so it varies of course but it's roughly 8-9 nanometers something like that this is a capacitor you have charge negative on one side an equal amount of charge but positively signed on the other side a gap and therefore an electric field between them is actually the situation that is described by even a parallel plate capacitor negative Q, positive Q a separation D and this thing has some surface area A that's a capacitor and in fact cell membranes are so difficult to measure in terms of their thickness using direct means the first way in which the cell membrane's thickness was ever actually measured was by measuring the capacitance to determine what separation of charge must exist that is what is the thickness of the cell membrane so the cell itself is a capacitor it may have an odd shape but it's effectively two parallel plates which have been bent into roughly spherical shapes and there's a separation of charge and that causes an electric field and that allows you to store energy that's a capacitor now of course human beings make capacitors custom built for different purposes in a wide array of such devices every one of these is a capacitor and what you can see if you look at them carefully in some cases they'll tell you for instance what the capacitance actually is so it's actually not incredibly obvious that it's written on any of these but usually you'll see a little number with an F, a capital F after it and that tells you in Farads ah, there's one of them so this is about a 5000 microfarad it looks pretty big but actually you can get capacitors that carry way more charge than this and are smaller than the thing that you see here microelectronic devices tend to have small capacitors in them like the ones down here and actually even these are big by modern standards these are the kinds of capacitors that when I was a kid yes, I would play with capacitors as a kid when I was a kid I would mess around with these are the ones you can actually handle by hand in the macroscopic world you have all kinds of extremely tiny capacitors that are all over the computer circuitry of iPhones, Android phones laptops, tablet computers car electronic components capacitors are an essential tool in storing and releasing energy for modern electronics an interesting place where you find capacitance and capacitors is actually every time you touch an iPhone touch screen most touch sensitive phones you use a technology known as a capacitive touch and as the name implies it essentially sets up a situation where the presence of your finger alters the way in which charge is distributed inside the bits and pieces of the screen the computer is programmed to detect and interpret those differences and by doing that it can determine where you've pressed even how firmly you've pressed on a surface and very accurately get pressure information and position information and translate that into responsiveness in the software in the operating system so for instance iOS 8 can respond to touch in very different ways swipe gestures touching, dragging and so forth and so all of that is made possible by capacitance and the ability to alter capacitance and detect those changes as they happen and interpret them as touch so that concludes this lecture on capacitors and capacitance please feel free to go back and review parts of this at your leisure the homework will cover material involving electric potential difference and then that concept applied to capacitors you'll have to do all kinds of things involving energy and capacitors calculating the capacitance and so forth so all of this should tie very neatly together for the next homework what we'll talk about in the next lecture in class is the discussion of capacitors by showing how you handle them when you see multiple capacitors in a circuit environment and then we'll talk a bit about how charge moves through a system and resistance to the motion of charge through a system this all leads up to something called Ohm's law which is an essential ingredient also in all electronics


This is FDA Patient Safety News. In this edition, a new stint to treat stenosis in the carotid artery, a caution about the importance of adjusting the dose of lovinox in patients with severe renal impairment, a new warning about serious hematologic and neurological events in patients on remicades, and a warning about causing fires with ethyl chloride spray. Stories and more on this edition of FDA Patient Safety News. Welcome to the program. For the U.S. Food and Drug Administration, I'm Mark Barnett. And I'm Anita Rayner. Let's start with some medical products FDA recently approved. The FDA recently approved the first stint system that's designed to treat stenosis in the carotid artery. It's called the Acculink Carotid Stint System and it's manufactured by Guyden Corporation. A stint, which is inserted during angioplasty, holds the carotid artery open. It's used with an umbrella-like filter called the Accunet that's designed to open up inside the vessel and catch emboli and other debris that might otherwise travel to the brain and trigger a stroke. In a clinical study, the stint system successfully opened blockages in 92 percent of 581 patients who received the device. The risk of death, stroke, and heart attack at 30 days or stroke in the area of the blockage at one year was about 10 percent in stint patients compared to 15 percent in patients who had surgery. In practice, the Accunet filter is inserted into a vessel in the groin and advanced to the site of the carotid blockage. The filter then opens to catch any debris. An angioplasty balloon is dilated to open the blockage. The stint is then threaded up to the blockage and when it's in place, the stint emerges from the catheter and opens automatically. Another balloon catheter is positioned inside the stint and debris is captured by the filter. The catheter is withdrawn and another one is inserted to close the filter and remove it along with any collected debris. The new stint system is designed for patients who need carotid revascularization but are at high risk from surgical endarterectomy. Patients for the stinting procedure must have at least a 50 percent synosis along with neurological symptoms or if they have no neurological symptoms, they must have at least an 80 percent synosis. Patients who should not receive this device include those who can't tolerate anti-coagulant or anti-platelet therapy, those with vascular anatomy that would preclude the safe introduction of a stint, and those with uncorrected bleeding disorders. FDA recently approved the first drug indicated for the management of neuropathic pain associated with diabetic peripheral neuropathy. The drug is called Simbalta or deloxatine hydrochloride and it's made by Eli Lillian Company. Simbalta, an SSNRI, was also recently approved to treat major depressive disorder in adults. Peripheral neuropathy is the most common complication of diabetes mellitus affecting up to 62 percent of American diabetics. It's usually associated with long-standing diabetes or poor glucose control and it's usually characterized by burning, tingling and numbing sensations that begin in the feet and later affect the legs or hands. Although the mechanism of action is unknown, in clinical trials patients treated with Simbalta reported a greater decrease in pain than those treated with placebo. In these trials, 51 percent of patients treated with Simbalta reported at least a 30 percent sustained reduction in pain as compared to 31 percent of placebo patients. The most commonly reported side effects were nausea, somnolence, dizziness, decreased appetite and constipation. Simbalta is contraindicated in patients with uncontrolled narrow-angle glaucoma and those taking MAO inhibitors. The FDA recently cleared for marketing a new screening test for newborns that will help detect a variety of inborn errors of metabolism. The test is called the Neogram Amino Acids and Acil Carnitine's Tandem Mass Spectrometry Kit and it's manufactured by Perkin Elmer Life and Analytical Sciences. The test starts with a heel stick blood sample from the infant, the same kind of heel stick sample that's already being used for other newborn screening tests required by various states. It applies mass spectrometry to the sample in order to measure amino acids, free carnitine and Acil Carnitine's. Abnormal patterns of these substances may indicate a wide variety of disease states including phenylketonuria, maple syrup urine disease and homocystinuria. While each of these conditions is relatively rare, taken together they're fairly common and they can cause developmental delay, seizures, mental retardation and death. With early identification, many of the effects of these diseases can be mitigated with improved long term outcome and quality of life. This product is not a standalone test for predicting inborn errors of metabolism, rather it's a screening tool that must be used along with clinical information and other tools to determine a newborn's risk. Aventus Pharmaceuticals has revised the labeling for the anticoagulant drug lovinox or anoxaparinsodium injection, stressing the need to adjust the dose in patients with severe renal impairment. That is those with a creatinine clearance of less than 30 milliliters per minute. These patients don't clear and eliminate the drug normally and so they may require a lower dose to prevent bleeding. The label notes that low weight patients and those with mild or moderate renal impairment don't require a specific dose of adjustment, but that low weight patients on the drug should be carefully monitored for bleeding. The label also contains a black box warning that cautions that patients on anticoagulant drugs who receive epidural or spinal anesthesia or who receive a spinal puncture are at risk of developing an epidural or spinal hematoma and that can result in long term or permanent paralysis. The black box warns that these patients should be frequently monitored for signs of neurological impairment and if neurologic compromise is noted urgent treatment is needed. It also recommends that physicians consider benefits versus risks before they decide on neroaxial intervention in patients who are receiving or will receive anticoagulant drugs. In randomized active controlled studies in patients with metastatic colorectal cancer the risks of a serious arterial thrombotic event was about 5% in patients who received a vast and along with 5FU based chemotherapy that's twice as high as the rate in patients who receive the 5FU regimen alone. Patients who are 65 years and older or who have a history of arterial thromboembolism are at higher risk for these events. The company says that patients who experience an arterial thromboembolic event or in treatment should permanently discontinue of Aston. Santicore Incorporated has notified healthcare professionals about new warnings for remicade or infliximab, a drug used to treat rheumatoid arthritis and Crohn's disease. The new safety information describes both hematologic and neurologic events that have occurred in patients being treated with remicade. The hematologic events, some of them fatal, have included leukopenia, neutropenia, thrombocytopenia and pansytopenia. Although it's not clear that remicade therapy causes these events and no high risk groups have been identified, Santicore advises practitioners to be cautious with patients who have significant hematologic abnormalities or a history of these problems. The company also says that all patients on remicade should be told to seek immediate medical attention if they develop signs suggestive of blood discrasies or infection such as persistent fever, bruising or bleeding. Practitioners should consider discontinuing remicade therapy in patients who develop significant hematologic abnormalities. The neurological events have included rare cases of a central nervous system manifestation of systemic vasculitis. Again, practitioners should consider discontinuing remicade in patients who develop significant CNS reactions. The Institute for Safe Medication practice has recently highlighted the dangers of using flammable medical products around heat sources. ISMP has cited cases where fires occurred because practitioners didn't realize that ethyl chloride spray, a topical skin anesthetic, is highly flammable. Ethyl chloride is the kind of old line medication that some people may just take for granted. It's been around for years. And it's used by a wide variety of people. Physical therapists use it to treat myofascial problems. Pediatrists use it before they do minor foot surgery. Dentists use it to test the vitality of tooth pulp. Athletic coaches and trainers use it for sports injuries. So people may not realize or may not remember that it's flammable. And it actually doesn't take a flame to ignite it. It doesn't. Electrical spark can do it. The static electricity can do it. Electrocotery can do it. In fact, that's what was used in one of the cases that ISMP cites. In this case, a nurse practitioner was preparing to treat a six-year-old child's infected toe. She sprayed his foot with ethyl chloride to numb the area, and then she lanced the area with surgical clotery. As soon as she triggered the clotery device, the entire surgical field went up in flames, and the pad underneath the child's foot ignited. The child's mother, who was holding her son, quickly pulled the child away from the fire, and luckily he wasn't burned. Later, the nurse practitioner admitted that she was unaware that ethyl chloride was very dangerous fire hazard, and it should never be used in the presence of electrical cotery equipment. She also mentioned that she'd observed the physician doing the same procedure previously in another child without any problems. Now, how close does the spray have to get to a possible source of ignition, like a spark or a cotery device, in order for it to ignite? It doesn't have to be too close. ISMP points out that the fumes, the vapors from ethyl chloride are heavier than air, and so they can sink to the floor and then move, and so you can have ignition at some distance source and then have flashback in which the flame comes back to the person using the ethyl chloride spray. So what's ISMP recommending? Well, there are two things. One of them has to do with the people who use the spray, and the other one has to do with the spray itself. First of all, they say make sure that all health care workers know about the dangers of flammable products, such as ethyl chloride, and that they understand the potential for burns when these products are used with a heat source. And second, they suggest that you reevaluate whether you really need each of the flammable products in your facility. ISMP says that there are often safer alternatives, especially for topical anesthetics. For more information on preventing surgical fires, go to our website. In an earlier program, we talked about several cases where a mix-up between tetanus-detheria-toxoid vaccine and tuberculin PPD led to unnecessary treatment. In that situation, both products were manufactured by the same company, Venice Pasteur. Since then, several more of these mix-ups have occurred, and some of them have involved products manufactured by other companies. Overall, we've received reports of over 80 cases of these kinds of mix-ups since 1990. So which of the two products is being used by mistake? Are patients who are supposed to be getting PPD, getting the tetanus-detheria-toxoid instead, or is it the other way around? Well, actually, mistakes are being made both ways. And not only that, sometimes PPD is being mixed up with vaccines other than the TD vaccine. Most of the mix-ups occurred with patients who were supposed to get PPD skin tests, but were inadvertently given intradermal injection of the TD vaccine. In some cases, the reactions from the TD injections were read as positive PPDs, and patients were started on isoniazid. And there are reports of the opposite mix-up occurring, where patients received intramuscular injection of PPD instead of receiving the TD vaccine. We've also gotten reports of similar mix-up errors between PPD skin tests and other vaccines, such as pneumococcal vaccine, flu vaccine, and hepatitis B vaccine. Why are these mix-ups happening? Well, one of the main factors appear to be the way the products are stored. Both the TD vaccine and the PPD require refrigeration, and they're often stored side-by-side. Another factor may be similar product packaging. Both of Venice Pasteur products come in stylized, colorful cartons of the same size. So, okay, what's FDA recommending to try to prevent these kinds of things from happening? Well, of course, the most obvious recommendation would be to carefully read the label before you administer the product, particularly where the packaging may look similar. But there are other things you can do, too. For example, consider storing these products separately. It's also a good idea to prepare only enough product for that particular patient at that particular time. And be sure to keep good records of lot numbers for vaccines and other injectable products. If your facility has barcode scanning technology, scanning the package could help to catch errors when dispensing or administering the product. You can report vaccine PPD mix-ups or send in suggestions on how to prevent such errors by going to our website. Well, that's all for this edition of FDA Patient Safety News. Remember, you can get more information on all the stories you've seen here today by visiting our website. We also urge you to use the website to report problems you've encountered with medical products. That's how we learn about problems so we can alert others. We'll be back next month with another edition, so watch for us. Until then, for the U.S. Food and Drug Administration, I'm Mark Barnett. And I'm Anita Rayner. See you next time.


So now when we think about the methods being used, if it was bookkeeping, you might have straight line method versus double declining. Straight lines, the baseline double declining, you depreciate more upfront. Makers method is now going to determine the amount of years we have, the class of the property, which is different from bookkeeping when you have more leeway to determine it. And then we'll talk more about the method, which is usually more of a double declining oftentimes method versus a straight line method, although that's a general rule. And then we're going to be depreciating it using some kind of convention now, which would be, and that last one was mid month versus mid year, mid quarter or something like that. All right, so the next one, mid quarter convention. Use this convention. If the mid month convention does not apply, and the total depreciation basis of makers property you placed in service during the last three months of the tax year, excluding non-residential real property, residential real property, any railroad grading or tunnel bore property placed in service and disposed of in the same year. And property that is being depreciated under the method other than makers are more than 40% of the total depreciable basis of all makers a property you placed in service during the entire year. Okay, so this gets a little bit funny because you might basically, most of the other property oftentimes you might have like a mid year convention, which would be the easiest kind of thing. Whenever you bought it during the year, you're going to get half the year of depreciation. Now, if you were going to try to manipulate this rule from the taxpayer standpoint, you would say, Hey, I'm not going to buy any equipment at the beginning of the year. I'm going to buy it all at the end of the year. Why? Because if I buy, if I buy all the equipment like in December, then they're still going to give me six months of depreciation at that point in time, even though even though I really only had one month because of a mid year convention. And that's why they might say, Well, no, we're not going to let you do that. We're going to force you to use a mid quarter convention in some cases. So you could see how that kind of pans out. Under this convention, you treat all property placed in service or disposed of during any quarter of the tax year as placed in service or disposed of at the midpoint of that quarter. Now, obviously tax software is useful to make some of these determinations. We need to know them in concept so that when people try to make those kind of more complex tax strategies, we can say, okay, wait, you're going to run into a problem if you try to depreciate or buy everything at the end of the year thinking you're going to get a half year of depreciation for it. So this means that for 12 months tax year, 11 over two months of depreciation is allowed for the quarter of the property is placed in service or disposed of. So if you use this convention, enter MQ, that's going to be the sign you might see change in your tax software to give you the method. So you would see an indication usually of a maker's method, double declining, possibly two D's and then an MQ instead of an MM, which would be mid month under column E in part three of form 4562 caution for purposes of determining whether the mid quarter convention applies the depreciable basis of the property, the place in service during the tax year reflects the reduction in basis for amounts expensed under section 179 and the part of the basis of property attributable to personal use. So 179 can kind of confuse the, you know, you might think that that might confuse your calculation in terms of when, you know, when you're going to get the deduction because you get the 179 in period one. So however, it does not reflect any reduction in basis for any special depreciation allowance. All right, then we've got the half year convention. So use this convention if neither the mid quarter convention nor the mid month mention convention applies. So in actuality, this is often like the default type of convention, right? Because a lot of the equipment you put on the books, if it's not real estate, which means you would have the mid quarter type, I mean mid month convention, if it was big real estate, that doesn't happen all the time. If you're then you're buying other stuff, machinery and equipment and stuff, you would think you would have the half year convention. The reason they did the half quarter convention first is because is because that would be the exception, right? You had the half year convention, but the way to think about it would normally be, okay, I'm going to put this machinery or whatever on the books, whatever I buy it, I'm going to imagine it's going to be depreciated in the middle of the year makers depreciation method according to the number of years they give me according to the classification of what I'm buying. And then usually double declining balance oftentimes we'll talk about that more later. And then I'm going to assume that it was bought in the middle of the year, which would be the half year convention, mid year convention, half year convention. Unless I bought a bunch of stuff at the end of the year, in which case the IRS would be assuming that I'm trying to take advantage of the half year or mid year convention, half year convention by taking six months of depreciation when I bought it all at the end of December, in which case I'm going to have to be kicked out possibly to using like a mid a mid quarter convention or something like that possibly. Okay, so under this convention you treat all property placed in service or disposed of during a tax year as placed in service or disposed of at the midpoint of the year. So this means that for a 12 month tax year, one half year of depreciation is allowed for the year the property is placed in service or disposed of if you use this convention enter HY. So that might be a little confusion. You might think it, I mean I keep saying mid year because everything else is mid and then here they went to half year, so HY, but half year. So you're going to see makers, usually a double D, double declining balance HY half year. So that's where you'd have an under column E and part three of form 4562. So see figuring the deduction for a short tax year later for information on the short tax year rules.


Hey there friends, how's it going? My name is Kevin and today we are going to watch dogs.   This is video sponsored by Ubisoft and we're going to be playing Watch Dogs Legion. I was confused why Ubisoft wanted me to just watch dogs. The game is out now if you want to check it out, there is a link in the description. Oh, okay, let's get started. I need one of these drones to just come in to your room if you don't click on that notification. You're trying to get some sleep and it's buzzing around, you're like, Investigate the threat to Parliament. I think that might be me. Do us a favor and keep it quiet, Dalton. I am just sprinting through the tunnels. I gotta save the queen. Oh my god, what is all of this? God, my guy is so cool. Why do I feel like he's gonna die? Okay, I don't mean to judge a book by its cover, but I'm pretty sure those are the bad guys, so I'm gonna shoot at them. I have a very confident spy. I think I'm done. I think all the baddies are gone. Oh no, no, no. There's more bombs to this area. Oh god, and more baddies. Do you think they know they're the baddies? They gotta know they're the baddies, right? Oh yeah, take your time. Yeah, take your time. It's grand. The bombs can wait, I'm sure. Okay, he did it. I still feel like he's gonna die, though. I just have that feeling. Oh no, it's okay. It's just one of my drones. Hey there, friends. How's it going? My name's Kevin. Killing thousands of... Okay, don't argue with the drones. Just watch this video, dude. Oh, they blew it up anyway. After all my efforts, he did die. Yes! Like, nothing. I'm happy he's dead. I'm just happy my guess was right. I guess all of the team are dead because I'm now a little spider. I am totally okay with this. I've always wanted this many legs. Honestly, you should. We have spiders. We have robot spiders. That's enough for anyone to be terrified of us. Who would win? One giant security company with the government or one spider boy? Because we just infiltrated them with one spider boy. Oh yes, I get to pick my first person. I like how some of them actually have valid attributes that would encourage you to pick them. Like, approached by Albion after hacking MMO servers. It could be good at hacking. They could be useful. And then we just have babysitter, banned for life from London Zoo. No details why. Also, why does she have a gun? They're inspiring beekeepers as well. Okay, they're top of my list so far. And they're Sagittarius, so it's just perfect for the team. All right, I think I'm going to go with the Sagittarius. Honestly, that took me a long time to pick. I'm just so confused by this person that I had to pick them. I don't know why they got banned from the zoo. Oh my god, it's the zoo people coming. They'll never find those elephants. Oh, I really want to go to the zoo. It's the zoo in the game. I know it's the one place I'm forbidden to go, but I think that's why I want to go there. Oh, what a great pub. Oh, I miss pubs. What kind of secret entrance is this? Oh my god. Okay, I've powered up your base. Oh no, the AI is realizing that we got framed for the bombings. So is Bagley just like Oralexa? Bagley, why am I banned from the zoo? Please tell me. If I told you it would ruin this running joke, now wouldn't it, Kevin? Bagley, buy zoo tickets. There you are.  I mean, hello. How are you? My thoughts exactly. I was thinking that those exact words. Now it would be irresponsible of us to release you naked and mulling into the wild. It would be. That's how I got banned from the zoo. I assume. Oh yeah, that's cool. Hello, it's nice to meet you. I don't know how you got in here. I just opened the place up, but I think we're supposed to fight now. So there you go. Hey, hey. Finish. Yes, finish, Connie. You're out of the organization now. Kill her. She just turns to me and I'm just sitting there like... I mean, we're kind of short on members, so probably shouldn't be killing them to be fair. Jesus, I was just coming up to say hello. Granted a little bit too close. I want to try and recruit someone. That's my main goal here, but I want someone like really old. You'll do. You're hench, mate. She's like 70. My friend is living with a rare blood disorder. Because the NHS is in a shambles, they weren't able to get their medication. I was going to make a joke how I'll go get their pills and then they'll join me and then that's actually pretty much what I'm doing. All right, we're going to help her out. I want to help out her friends so she'll join our crew.  Low mobility. No cover or sprint. Yeah, we need her on the team. I'm untracking the main quest and I'm tracking this one. This is all I have interested right now. Is this how you take a bus? I don't know. I don't use public transport because I never leave the house. Okay, that's just a little fender bender. That's fine. Well, for me, it's a fender bender. For him, his cars are right off.  There's probably so many people just on the side of the road like, ah, good, my bus is coming. I just speed-bassed them in the wrong lane. Oh, another opportunity for a ramp. Hack it. Yes. Get some air time. Oh, sorry. Sorry. Okay, the doctor's near here somewhere. Luckily, the bus stops right here. Fantastic. How convenient. Okay, how do I get up? It looks like they're on the roof. Oh, good. Put on your disguise. Yes. Oh, oh, no. Oh, no. I'm messing with some serious people here. What is this old woman involved in? I got you. I got you. Easy. Okay, not so easy. Ow. The box provides little to no protection. Okay, at least I won in the end. Wasn't as smooth as I would have liked. Oh, he's coming in. You know what? That might be for the best. I can surprise him. Yes. Oh, no. He is a weapon. Ow. Oh, I'm the trap. Oh, I almost killed myself with that. Good thing I was wearing my box. Wait, where did you come from? What the? Where did you come from? Oh, you were up there. Oh, no. I ducked on arm due by accident. Okay, great. Okay, good. You can do that. I was not sure if that would work. I just have to escape the area, and then I can find out where the doctor is. There was a ladder up this way the entire time, by the way, that I missed earlier. I could have parked my bus here and just climbed on the roof. I'll move it. I'll move it. Just remember to thank me. I'm the bus driver. I'm detecting. Oh, that was the city's fault. Sue the city. Honestly, you'll get loads of money right now. I got to get in here. I have to steal the medical van? Thought I'd just have to beat up a doctor. Well, that was a good route. You just need time to figure out what's going on here. Oh, God, he's got a gun. There's explosive barrels right there, and they're scaring me. Hold on, hold on, hold on. Yes, I'm getting good at this fighting thing. I might have to get the key to the garage. I don't think I can just ramp this van off the roof. There we go. Awesome. Let's get this ambulance out of here. I was so excited to play this game for multiple reasons, but one of them was the fact that it's set in London, and I wanted to explore London in this game, and all I've been doing is driving a bus and now an ambulance. Oh, should I open that first? Sorry, I'm new with the hospital. I can't wait to get this ambulance full of drugs to that old lady. Like, this is not for her friend. She is a dealer. She's got to be dealing out all these drugs. If you need anything at all, I'm at your service. That's what I wanted to hear. Hold Tab to swap. Oh, I get to be an old lady. I can go to the zoo as many times as I want, and I might even get a senior discount or something.  Brilliant. I'm not ready to go to pasture yet. Oh, amazing. This is as fast as I can go. Our background's a bit weird. She studied law while incarcerated. She has unusual income patterns. She's a diplomat earning 156,000 a year, and she's the subject of a missing person's report. There's more to Lena than meets the eye. She can't use cover at all. I'm not making the game harder. I'm just making it more realistic. I'm old. I have sore joints. Please, I can ride the bus for free, I believe. Okay, I deactivated the bus. Oh, God, I shifted the bus in reverse. I'm sorry. No, no, no, no, no, no. Come back. Oh, no, I've definitely killed someone. Bear Knuckle League. I was just visiting Chinatown, but I'd love to get involved. You like Bear Knuckle? You think you're tall? Huh? She's lost. Unavailable for low mobility operatives. Oh, man. Don't discriminate. It's poor Lena or whatever her name is. I'm going to get her new clothes. You may have low mobility, but you're going to look fresh. Oh my God. I didn't mean to. Sorry. I'll just give you some cool boots, and we'll leave it at that, will we? Oh my God, she may be low mobility, but look at her climb that pipe. Okay, her joints are better than mine. Another old lady.  Deep breaths, dear. Why are you so aggressive? I thought you were with them. Do I look like I'd be with them? Do I look like I'd be with anyone? Could you not hack the system for me and see just what the hell is going on? I really want her on the team, but I do have other stuff to be doing as well. I just want a team of old ladies. Okay, my first stop is up there. Unless there's a pipe. I don't know how I'm supposed to get up there. If there's a pipe happy days, because she will fly up that. Oh wait, I was supposed to just admire their billboard. Okay, that's not too bad. Okay, good. A scissor lift. Great. It means I don't have to take the stairs.  Oh my God, that's amazing. All right, up we go. Be careful now. Perfect. I'm way too high with it. This poor woman. Like where's the other one that they actually trained while this poor old lady is doing all the hard work? She's probably at the zoo. I bet she's at the zoo. Oh no, they have to jump this gap. Can you do this? No. How am I supposed to get across? Can my spider do it? Do I have it? Oh, thank God, because that really was just not gonna happen. Okay, now I just need to steal their plans. Hopefully this will be less moving around. Excuse me, please. I need medical assistance. And by that, I mean your vehicle. Get out. I tried to raise the thing so I'd ramp over the bike and it would look cool, but it didn't come up in time. So I just killed him. All right, I'm here. Where even is this place? It doesn't look like I should be anywhere near here. You stealth. I don't think that's my strong suit. In fact, I don't think she has any strong suits except for her suit, which is a strong suit. Great choice. It looks like it's inside, but how do I get in there? The little taser. I love that takedown. I hope that armor isn't tasteproof. Oh, I just slapped him instead. Okay, that wasn't the greatest of attacks. There we go. The best part about this is no one will believe you. Who did this?  No stair lift here. Come on, power through. Now, what are we even here for? Some operation data. Mind. This list can actually help us find like-minded allies willing to help us. Well done. Thank you. I appreciate that. I've proved that old women are an asset to the team. Great. I can get a little odd job as a courier. The dead metal. So I moped. There you go. There's your package. Another job well done by Lady Lina. Oh, finally, I can hear somebody. Thank you for bringing your megaphone. All right, you know what? I would love to play more of this, but I think we should end it there. Thank you, Ubisoft for the sponsor. This game is an absolute blast. I really love how it looks so far. I really, really enjoyed that. And thank you very much for watching. I really appreciate it. If you want to check out Watch Dogs for yourself, there's a link in the description. You can check it out there. I got a twitch in the description and I got a second channel where I upload some clips there as well and they've been going over well. So I'm glad people are enjoying them, but yeah, that's the end of this one. So thank you very much for watching and I hope to see you next time. Bye for now.


So people a quick video today regarding Cyberpunk 2077 and this well you could call a leak it's one I'd say you can call more legit because of where it originated so let's go. How's it going guys my name's DPJ and if you enjoyed the video leaving a like really helps out and if you like what you see and want to see more be sure to subscribe. Also guys I apologise about my voice I have got a crazy cold and it's absolutely killing me. Okay so we've had many leaks pop up regarding the patch 1.5 for Cyberpunk and the ultimate arrival of the next generation version of the game for basically Xbox Series X and the PS5 is something many of us fans have been waiting for for a long while now. Now these leaks have really showcased a lot of what we'd expect for some state brand new features and whatnot but at the end of the day nothing has been confirmed on CDPR's behalf about these leaks besides the fact they just deny they're real but today's one is pretty important because it's an official image that has been found. So the image you can see on screen now it's of the old soul familiar female V. This character we've seen in many promotions before pollsters, trailers and whatnot but this is a brand new post and this image you can't find anywhere else on the internet but you couldn't before today. Now it's absolutely everywhere and this image was actually found by a company called PlayStation Size who normally searched a PlayStation database for interesting details about upcoming games and they stumbled across this brand new Cyberpunk poster. Interesting they go on to say it's for the PS5 native version which we do know is coming. Also interesting they do state they think it will release mid-February to early March. I don't know why they say this and do think it's a guess as I couldn't seem to find anything else on this and why this date I will state it would be a brave move on CDPR's behalf because that's a busy period for other games for sure. So this three next generation upgrade obviously if you own the best game will drop sometime this year. It's been leaked that the games getting their stuff relaunched. This new poster kind of ties in with that I guess but in saying that it could be for anything. Either way guys it's new and I'd really expect to see new information about the Cyberpunk 1.5 patch very soon indeed. The fan base for this game is still massive and I know many of us are excited for the next generation version of this game basically the version the game should have been at release.  But on that note the end of the video has arrived I told you a short but sweet one. If you guys enjoyed the video leaving a like really helps out and if you like what you see and want to see more Cyberpunk be sure to subscribe. But thanks as always for stopping by and hopefully I will see you on that next. One.