diff --git a/courseware/static/subs/fDtrSZ69xII.srt.sjson b/courseware/static/subs/fDtrSZ69xII.srt.sjson new file mode 100644 index 0000000000..54fa279eb1 --- /dev/null +++ b/courseware/static/subs/fDtrSZ69xII.srt.sjson @@ -0,0 +1,533 @@ +{ + "start": [ + 0, + 760, + 5550, + 7730, + 15040, + 22780, + 26410, + 31490, + 35630, + 37015, + 39890, + 47340, + 49390, + 53330, + 56170, + 59924, + 61630, + 65640, + 72340, + 75120, + 80660, + 83550, + 88110, + 92500, + 96538, + 99170, + 103910, + 113990, + 118090, + 121540, + 125630, + 128211, + 131510, + 135680, + 139700, + 142190, + 145380, + 149430, + 151048, + 154330, + 159440, + 164260, + 166990, + 170886, + 174520, + 176040, + 179664, + 190760, + 196600, + 201060, + 203958, + 207444, + 211940, + 217210, + 220450, + 223430, + 224640, + 226290, + 228162, + 233830, + 238620, + 239640, + 242880, + 246200, + 249490, + 257300, + 260600, + 262290, + 265810, + 269740, + 275500, + 278270, + 281910, + 284090, + 286260, + 289730, + 293659, + 296010, 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a look at some of the", + "properties of linearity.", + "What does linearity bias?", + "", + "In particular, linearity will bias homogeneity and", + "superposition.", + "Let's take a look at each of these in turn, and see what", + "homogeneity and superposition really means.", + "", + "So let's start with homogeneity.", + "", + "So suppose I have a system in a little box, and let's assume", + "it's a linear system.", + "I apply a set of inputs, x1, x2, and so on, to", + "produce an output y.", + "So in my facetious example here, think of", + "the inputs as apples.", + "And the processing produces a ripe apple.", + "", + "Now, what homogeneity says is this.", + "In the same system, if I feed it with fraction of apples,", + "then I will get fraction of ripe apples at the output.", + "In other words, if each of my inputs is multiplied by some", + "constant, alpha, then my outputs will also be", + "multiplied by the same fraction, alpha.", + "", + "This simply says that if I reduce my inputs by some", + "proportion, then my outputs will also reduce by the same", + "proportion So that's homogeneity.", + "", + "Next, let us look at superposition.", + "This is some really fun stuff.", + "", + "So suppose I have a linear system as before.", + "And in this case, I give it one set of inputs,", + "x1a, x2a, and so on.", + "And for fun, let the a's stand for apples.", + "So if you have a set of apples, and let's say I get", + "applesauce at the output.", + "", + "Now, if I take the same circuit, and if I feed the", + "main same circuit a different set of inputs-- x1b, x2b, and", + "so on, in this case, b stands for blueberries--", + "let's say I get blueberry jam as an output.", + "", + "So what supervision says is this.", + "If I take the same circuit, the same system, and if at", + "each input where I had previously fed", + "an apple or a blueberry.", + "The [UNINTELLIGIBLE]", + "at each of the inputs, I want to feed", + "an apple and a blueberry.", + "That's x1a + x1b, x2a + x2b, and so on.", + "Then the outputs will simply be the sum of the", + "two original outputs.", + "So they could be ya plus yb.", + "You facetiously think of it as mixed fruit jam.", + "", + "So superposition simply says that if I find the output by", + "feeding the system apples, find the output by feeding the", + "system blueberries.", + "If I fed the same system the sum of apples and blueberries,", + "then I could compute the output simply by looking at", + "the outputs of the system in which I fed just apples or", + "blueberries.", + "Let's look at a specific superposition example and get", + "a sense of what this means.", + "So here's the same system.", + "And in this case, I want to feed two voltages, v1 and v2,", + "and I want to find out the output.", + "What superposition says is this.", + "", + "I can take the same system, and set one output to zero,", + "and feed it just v1, and measure an output.", + "Similarly, I take the same system.", + "And this time around, set v1 to v0, and feed it v2, and I", + "obtain a net output.", + "", + "By the method of superposition, what it says is", + "that for the same system, if I feed it the sum of the two", + "inputs, then I can get my output simply by summing up", + "the two individual outputs.", + "In other words, I can obtain the effect of v1 and v2 acting", + "as inputs simply by taking the same circuit and applying one", + "input, setting the others to zero.", + "Measuring the output.", + "", + "Setting the second input.", + "", + "And then having all the other inputs be zero.", + "And measure the output.", + "And then take the individual outputs, y1 and y2, and simply", + "add them up.", + "And that would be the result of v1 and v2 acting together.", + "So that is a specific superposition example.", + "What it does is it allows us to solve two", + "problems, p1 and p2.", + "But each of them is a simpler problem, and simply sum the", + "two outputs of the simple problem to obtain the result.", + "", + "So method of superposition can be summarized as follows.", + "", + "You first find the response of the circuit to each source", + "acting alone.", + "And then second.", + "", + "If you want to find the response of the sources acting", + "together, then you simply sum the individual responses.", + "It is important to point out that this works only for", + "independent sources.", + "", + "You will see later how superposition works with", + "dependent sources.", + "", + "Now, in circuit position, we talked about each source", + "acting alone.", + "And for each source to act alone, I had to set all the", + "other sources to zero.", + "So what does it mean to set a source to zero?", + "So let's say, for example, I have a voltage source, as", + "shown here.", + "What does it mean to set that this voltage source to zero?", + "Well, it simply means that we will short the voltage source", + "as shown here.", + "That sets a voltage source to zero.", + "Similarly, for a current source.", + "The way you set the current source to zero is you open", + "circuit the third course.", + "", + "OK, now let's get back to our original example that we had", + "previously solved using the known method.", + "So let's go ahead and solve the same circuit using the", + "superposition method.", + "", + "OK, using the superposition method for the goal, I have to", + "find the output for each source acting alone.", + "And then I sum the outputs.", + "So let me start by finding the output with v acting alone.", + "So we'll start by setting the current source to zero.", + "And I can do that by open circuiting the current source.", + "", + "Now, as I do this, I can compute the", + "output, ev, as follows.", + "ev is simply this voltage appearing at the output", + "through a voltage divider, r1 and r2.", + "So I get r2 divided by r1 plus r2 times v. So that is a", + "component of the output as a function of v alone.", + "", + "OK, next, let me work on i acting alone.", + "So this case with i acting alone, I want to set the", + "voltage source to zero by shorting it.", + "Now, I can write ei, the component of the output that", + "relates to just a current source, as follows.", + "So I have the current flowing through here, and that current", + "flows through a parallel resistor pair.", + "And so the voltage is simply the current times the", + "effective resistance, which is simply r1 parallel r2, which", + "is given by r1, r2 divide by r1 plus r2.", + "So that gives me ei.", + "", + "So the superposition method simply says that you get the", + "effect of both sources acting simultaneously if I simply add", + "up the two components, ev and ei, like so.", + "There you go.", + "So this is due to the voltage source acting alone.", + "And this is due to the current source acting alone.", + "Notice that this equation is the same as the one you got", + "with the application of the load method.", + "" + ] +} \ No newline at end of file