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Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:02.51,0:00:04.77,Default,,0000,0000,0000,,Welcome to the introduction\Nto electrical and
Dialogue: 0,0:00:04.77,0:00:07.21,Default,,0000,0000,0000,,computer engineering at\Nthe University of Utah.
Dialogue: 0,0:00:07.21,0:00:11.71,Default,,0000,0000,0000,,I am Dr. Cynthia Furse, a professor of\Nelectrical and computer engineering.
Dialogue: 0,0:00:11.71,0:00:14.96,Default,,0000,0000,0000,,Today we're going to be talking\Nabout units and scientific notation.
Dialogue: 0,0:00:16.13,0:00:19.24,Default,,0000,0000,0000,,We're going to review the units that\Nwe'll be using throughout the semester.
Dialogue: 0,0:00:19.24,0:00:21.62,Default,,0000,0000,0000,,We'll also review scientific notation, and
Dialogue: 0,0:00:21.62,0:00:25.14,Default,,0000,0000,0000,,talk about converting between\Nunits in scientific notation.
Dialogue: 0,0:00:25.14,0:00:29.30,Default,,0000,0000,0000,,The reason this is important is because\Nelectrical engineers use very large and
Dialogue: 0,0:00:29.30,0:00:31.04,Default,,0000,0000,0000,,very small numbers all the time,
Dialogue: 0,0:00:31.04,0:00:33.87,Default,,0000,0000,0000,,meaning that we need several\Ndifferent types of units.
Dialogue: 0,0:00:33.87,0:00:38.67,Default,,0000,0000,0000,,I've chosen an example here of\Na company that's selling capacitors.
Dialogue: 0,0:00:38.67,0:00:41.95,Default,,0000,0000,0000,,You can see that they're giving\Nthe capacitance in picofarads.
Dialogue: 0,0:00:41.95,0:00:44.88,Default,,0000,0000,0000,,The voltage ratings are in volts and\Nkilovolts.
Dialogue: 0,0:00:44.88,0:00:47.62,Default,,0000,0000,0000,,The tolerance is either in percent or\Npicofarad,
Dialogue: 0,0:00:47.62,0:00:51.25,Default,,0000,0000,0000,,and the temperature coefficient\Namounting type are used.
Dialogue: 0,0:00:51.25,0:00:52.22,Default,,0000,0000,0000,,So if you are searching for
Dialogue: 0,0:00:52.22,0:00:55.42,Default,,0000,0000,0000,,a capacitors day, these are the units\Nthat you would have used.
Dialogue: 0,0:00:56.56,0:00:59.85,Default,,0000,0000,0000,,We're going to use the international\Nsystem of units in this class,
Dialogue: 0,0:00:59.85,0:01:01.20,Default,,0000,0000,0000,,the SI units.
Dialogue: 0,0:01:01.20,0:01:05.18,Default,,0000,0000,0000,,You'll remember these of course from\Nphysics, or from your previous experience.
Dialogue: 0,0:01:05.18,0:01:09.61,Default,,0000,0000,0000,,The units of length is meters,\Nmass, kilograms, time,
Dialogue: 0,0:01:09.61,0:01:13.54,Default,,0000,0000,0000,,seconds, temperature, kelvin,\Nvoltage is a volt, and
Dialogue: 0,0:01:13.54,0:01:16.01,Default,,0000,0000,0000,,here's the symbol that we're\Ngoing to be using for that.
Dialogue: 0,0:01:16.01,0:01:17.72,Default,,0000,0000,0000,,Current is given in amperes.
Dialogue: 0,0:01:17.72,0:01:20.21,Default,,0000,0000,0000,,Here's the symbol that we'll be using for\Ncurrent.
Dialogue: 0,0:01:20.21,0:01:21.82,Default,,0000,0000,0000,,Charge is coulombs.
Dialogue: 0,0:01:21.82,0:01:25.89,Default,,0000,0000,0000,,Resistance is ohms and here's the symbol\Nwe'll be using for resistance.
Dialogue: 0,0:01:25.89,0:01:29.61,Default,,0000,0000,0000,,Capacitance is farads and\Nhere's the symbol for capacitors.
Dialogue: 0,0:01:29.61,0:01:34.12,Default,,0000,0000,0000,,Inductance is henrys,\Npower is watts, frequency is hertz.
Dialogue: 0,0:01:34.12,0:01:38.14,Default,,0000,0000,0000,,I've also given you the relationship\Nbetween the various SI units for
Dialogue: 0,0:01:38.14,0:01:39.58,Default,,0000,0000,0000,,our electrical components.
Dialogue: 0,0:01:41.39,0:01:45.74,Default,,0000,0000,0000,,When we talk about very large, or very\Nsmall numbers, we use special prefixes.
Dialogue: 0,0:01:45.74,0:01:47.40,Default,,0000,0000,0000,,You've seen these before.
Dialogue: 0,0:01:47.40,0:01:49.86,Default,,0000,0000,0000,,Prefixes that are very common\Nin electrical engineering.
Dialogue: 0,0:01:49.86,0:01:54.51,Default,,0000,0000,0000,,For example, if we were talking about\Nfrequency of wireless communication units,
Dialogue: 0,0:01:54.51,0:01:59.62,Default,,0000,0000,0000,,would be giga, hertz, or megahertz,\N10 to the 9 hertz, or 10 to the 6th.
Dialogue: 0,0:01:59.62,0:02:04.31,Default,,0000,0000,0000,,Kilovolts, for example,\N10 to the 3rd will be a large voltage.
Dialogue: 0,0:02:04.31,0:02:07.37,Default,,0000,0000,0000,,If we were talking about\Nnumbers that are very small,
Dialogue: 0,0:02:07.37,0:02:12.59,Default,,0000,0000,0000,,10 to the -3 to 10 to the -18 for example,\Nwe would be using these prefixes.
Dialogue: 0,0:02:12.59,0:02:16.64,Default,,0000,0000,0000,,For example, capacitors are commonly\Nsold in pico or nanofarad or
Dialogue: 0,0:02:16.64,0:02:18.44,Default,,0000,0000,0000,,sometimes microfarad.
Dialogue: 0,0:02:18.44,0:02:24.65,Default,,0000,0000,0000,,We'll commonly find inductors\Nin microhenrys or millihenrys.
Dialogue: 0,0:02:24.65,0:02:28.94,Default,,0000,0000,0000,,Milli is 10 to the minus 3rd,\Nmicro, 10 to the minus 6, nano,
Dialogue: 0,0:02:28.94,0:02:30.90,Default,,0000,0000,0000,,10 to the minus 9th and so on.
Dialogue: 0,0:02:33.82,0:02:38.19,Default,,0000,0000,0000,,There are several naming conventions that\Nare used in our textbook and others.
Dialogue: 0,0:02:38.19,0:02:41.29,Default,,0000,0000,0000,,Current is given as i, and voltage as v.
Dialogue: 0,0:02:41.29,0:02:45.06,Default,,0000,0000,0000,,Whether they're straight or italicized,\Nthese may or may not be time varying,
Dialogue: 0,0:02:45.06,0:02:47.60,Default,,0000,0000,0000,,they're just general used letters.
Dialogue: 0,0:02:47.60,0:02:50.13,Default,,0000,0000,0000,,Time varying constants,\Ncurrent and voltage,
Dialogue: 0,0:02:50.13,0:02:53.93,Default,,0000,0000,0000,,have this parentheses t, indicating\Nthat they are functions of time.
Dialogue: 0,0:02:53.93,0:02:56.00,Default,,0000,0000,0000,,They are not constant.
Dialogue: 0,0:02:56.00,0:02:59.65,Default,,0000,0000,0000,,Values that are constants are DC or\Ndirect current.
Dialogue: 0,0:02:59.65,0:03:03.37,Default,,0000,0000,0000,,They are capitalized I and V shown here.
Dialogue: 0,0:03:03.37,0:03:05.94,Default,,0000,0000,0000,,Bold letters aren't something special.
Dialogue: 0,0:03:05.94,0:03:10.09,Default,,0000,0000,0000,,In our book, these are typically matrices,\Nvectors, phasors, Laplace or
Dialogue: 0,0:03:10.09,0:03:11.24,Default,,0000,0000,0000,,Fourier transforms.
Dialogue: 0,0:03:12.74,0:03:16.55,Default,,0000,0000,0000,,When we want to convert from\Nunits to scientific notation,
Dialogue: 0,0:03:16.55,0:03:20.05,Default,,0000,0000,0000,,what we do is we take the unit\Nthat we want such as milli,
Dialogue: 0,0:03:20.05,0:03:24.26,Default,,0000,0000,0000,,and we just multiply the value by\Nthe number that goes with milli.
Dialogue: 0,0:03:24.26,0:03:28.91,Default,,0000,0000,0000,,So for example,\N1 MV is 1 times 10 to the -3 volt.
Dialogue: 0,0:03:28.91,0:03:33.05,Default,,0000,0000,0000,,1 MV is 1 times 10 to the 6 volt.
Dialogue: 0,0:03:33.05,0:03:37.18,Default,,0000,0000,0000,,If we want to convert from scientific\Nnotation back to units, what we do is
Dialogue: 0,0:03:37.18,0:03:41.72,Default,,0000,0000,0000,,we take our scientific notation value,\Nlet's say 1 times 10 to the 6th, and
Dialogue: 0,0:03:41.72,0:03:45.15,Default,,0000,0000,0000,,then we divide by the value\Nassociated with the unit we want.
Dialogue: 0,0:03:45.15,0:03:50.09,Default,,0000,0000,0000,,Mega, for example, is 10 to the 6th,\Nso we divide by 10 to the 6.
Dialogue: 0,0:03:50.09,0:03:53.90,Default,,0000,0000,0000,,1 times 10 to the 6 is going\Nto give us one megavolt.
Dialogue: 0,0:03:53.90,0:03:55.39,Default,,0000,0000,0000,,Let's do this from millivolt.
Dialogue: 0,0:03:55.39,0:03:59.90,Default,,0000,0000,0000,,1 times 10 to the -3 volt,\Ndivided by the 10 to the -3.
Dialogue: 0,0:03:59.90,0:04:02.19,Default,,0000,0000,0000,,Which is associated with a millivolt.
Dialogue: 0,0:04:02.19,0:04:04.58,Default,,0000,0000,0000,,And that's going to give us 1 millivolt.
Dialogue: 0,0:04:05.98,0:04:09.61,Default,,0000,0000,0000,,If we want to convert from one unit\Nto another, let say from millivolt to
Dialogue: 0,0:04:09.61,0:04:14.01,Default,,0000,0000,0000,,microvolt, sometimes you can just\Nsee how to do this, that's fine.
Dialogue: 0,0:04:14.01,0:04:18.41,Default,,0000,0000,0000,,But I'm also going to show you an easy way\Nto do this with just to match the units.
Dialogue: 0,0:04:18.41,0:04:21.34,Default,,0000,0000,0000,,We're going to use this throughout\Nthe semester periodically
Dialogue: 0,0:04:21.34,0:04:23.52,Default,,0000,0000,0000,,when we have calculations to do.
Dialogue: 0,0:04:23.52,0:04:27.82,Default,,0000,0000,0000,,Let's say, for example, we want to know\Nhow many microvolts are in one millivolt.
Dialogue: 0,0:04:27.82,0:04:32.47,Default,,0000,0000,0000,,So here's question mark, how many\Nmicrovolts, and here's the 1 millivolt.
Dialogue: 0,0:04:32.47,0:04:35.76,Default,,0000,0000,0000,,Well, what we need to do is\Nmatch units from this microvolt,
Dialogue: 0,0:04:35.76,0:04:38.80,Default,,0000,0000,0000,,which we have to this\Nmillivolt that we want.
Dialogue: 0,0:04:38.80,0:04:42.01,Default,,0000,0000,0000,,So, microvolt is 10 to the -6 volt.
Dialogue: 0,0:04:42.01,0:04:42.99,Default,,0000,0000,0000,,Are we there yet?
Dialogue: 0,0:04:42.99,0:04:45.78,Default,,0000,0000,0000,,Nope, we haven't gotten our\Nmillivolt taken care of.
Dialogue: 0,0:04:45.78,0:04:49.89,Default,,0000,0000,0000,,Let's say now, we want to get rid of\Nthe volts and we want millivolts instead.
Dialogue: 0,0:04:49.89,0:04:53.02,Default,,0000,0000,0000,,So, we're gonna say 10 to\Nthe minus 3rd volt per millivolt.
Dialogue: 0,0:04:53.02,0:04:55.91,Default,,0000,0000,0000,,One millivolt is 10 to the minus 3rd volt.
Dialogue: 0,0:04:55.91,0:04:58.82,Default,,0000,0000,0000,,And then we're gonna multiply\Nthis by 1 millivolt.
Dialogue: 0,0:04:58.82,0:04:59.84,Default,,0000,0000,0000,,Now look what would happen.
Dialogue: 0,0:04:59.84,0:05:02.96,Default,,0000,0000,0000,,We would be able to cancel out the volts.
Dialogue: 0,0:05:02.96,0:05:05.19,Default,,0000,0000,0000,,We'd be able to cancel out the millivolts.
Dialogue: 0,0:05:05.19,0:05:07.10,Default,,0000,0000,0000,,And we'd be left just with microvolts.
Dialogue: 0,0:05:07.10,0:05:08.81,Default,,0000,0000,0000,,Hey, that's what we wanted.
Dialogue: 0,0:05:08.81,0:05:13.95,Default,,0000,0000,0000,,The math here would be 10 to the -6 on the\Nbottom, 10 to the minus 3rd on the top.
Dialogue: 0,0:05:13.95,0:05:16.74,Default,,0000,0000,0000,,That gives us a value of 10\Nto the minus 3rd microvolts.
Dialogue: 0,0:05:16.74,0:05:21.25,Default,,0000,0000,0000,,1 millivolt is indeed 10\Nto the 3rd microvolts.
Dialogue: 0,0:05:21.25,0:05:24.29,Default,,0000,0000,0000,,Another way to do this is you\Ncan start with what you have.
Dialogue: 0,0:05:24.29,0:05:28.60,Default,,0000,0000,0000,,We have 1 millivolt and\Nwe want to know how many microvolts.
Dialogue: 0,0:05:28.60,0:05:30.30,Default,,0000,0000,0000,,So we take 1 millivolt.
Dialogue: 0,0:05:30.30,0:05:34.29,Default,,0000,0000,0000,,We know that a millivolt,\N1 millivolt is 10 to minus 3rd volt.
Dialogue: 0,0:05:34.29,0:05:36.77,Default,,0000,0000,0000,,So here's how we can convert\Nmillivolts to volts.
Dialogue: 0,0:05:36.77,0:05:37.90,Default,,0000,0000,0000,,Nope, that's not we wanted.
Dialogue: 0,0:05:37.90,0:05:39.52,Default,,0000,0000,0000,,We wanted to get to microvolt.
Dialogue: 0,0:05:39.52,0:05:41.81,Default,,0000,0000,0000,,Now let's convert volts to microvolts.
Dialogue: 0,0:05:41.81,0:05:44.56,Default,,0000,0000,0000,,1 microvolt is 10 to the -6 volts.
Dialogue: 0,0:05:44.56,0:05:48.24,Default,,0000,0000,0000,,Are volts we cancel out,\Nare millivolts we cancel out,
Dialogue: 0,0:05:48.24,0:05:51.14,Default,,0000,0000,0000,,leaving us with 10 to the 3rd microvolt.
Dialogue: 0,0:05:51.14,0:05:56.14,Default,,0000,0000,0000,,So in conclusion, we've reviewed\Nthe units that we'll be using.
Dialogue: 0,0:05:56.14,0:05:57.90,Default,,0000,0000,0000,,We've reviewed scientific notation and
Dialogue: 0,0:05:57.90,0:06:00.76,Default,,0000,0000,0000,,we've talked about how to convert\Nfrom one unit to another.
Dialogue: 0,0:06:01.85,0:06:05.66,Default,,0000,0000,0000,,Throughout the semester, I'm going to\Ninclude a picture on each of our lectures
Dialogue: 0,0:06:05.66,0:06:09.01,Default,,0000,0000,0000,,of some of the beautiful places\Nin the Great State of Utah.
Dialogue: 0,0:06:09.01,0:06:11.80,Default,,0000,0000,0000,,This is Delicate Arch in\NArches National Park.
Dialogue: 0,0:06:11.80,0:06:16.05,Default,,0000,0000,0000,,Near Kanab, Utah, clearly one of the\Nsignature pictures from the state of Utah.