so in this lesson here we have only two small objectives here the first objective is we're going to examine SI units and understanding what they are and then we're also going to look at engineering notation which is essentially just scientific notation with a slight modification that we use in engineering so SI units which basically were established in 1960 and there's like I think in a Latin or French name for it but I just think of it this is standard international units and of course this is so that we you know if we say one gram of something anywhere in the world we know what one gram is you know so some of the standard units that you might be familiar with like our meters if you've taken chemistry there's moles temperature you might think Celsius but it's actually Kelvin and mass is gram or sometimes people say it's kilogram but I actually think it's gram that is used for the standard international unit here and so let's look at the standard international units we will use for this course now we're just gonna look at the units here right now we'll talk about and the next lesson or two about what these things are well we're gonna have something here that you might be familiar with charge and you're actually probably familiar charge everyone has you know gotten a static electric shock before and basically what you're doing is you're building up a charge on either your body or whatever it is you're using to give someone a shock on and then basically you're making contact with another conductor and actually technically you're not making contact technically you're ionizing the air and you actually get a small bolt of lightning and I say bolt of lightning it's a bolt of electricity between you and the device that you're touching and the standard unit for this is the Coulomb which we denote with C now we have to be careful with this that you don't think of this as temperature and the easiest way to know it's not temperatures we don't have degrees C here it's just C 4 Coulomb we won't use Coulomb too much in this course but it is the foundation for everything dealing with electricity and then we have the that's the unit current in a circuit and the unit for this is ampere which we often just abbreviate as amp and the letter we use for that is just a capital a to represent amp and then there is something that we will have as voltage which again that's something at least all familiar with the some extent because we've all used batteries before and had like a 9-volt battery or your car as a 12-volt battery I'm so we're all familiar at least with what the voltage is as far as we've seen it before we just might not know where it comes from and voltage what's kind of funny is it well that's the name and that's also the unit is volts and we use that as a capital V for abbreviation and then the other one that we're going to be using quite a bit here is power and power of course is how much I like to think of it is how much power is being delivered but basically kind of the energy be delivering how much you know electricity you're using how much ability you have to do some work so power and this is actually going to have a unit of watts which we'll talk about in more detail and that's just a W now those are the things that you know we would quote measure in a circuit that we're going to be primarily interested in some of the other things though is we'll have electrical components which you might be familiar with some of these resistors and they have something called a resistance and that's measured in ohms and the symbol for this though is the Greek letter and I always do a pretty crappy job of drawing it by hand it's the Greek letter capital Omega kind of looks like the horseshoe and then we also have capacitors and the units for this are farad's and that is a capital F and that's actually farad's is named after faraday was a physicist who did a lot of investigation with this and with capacitors and you know he might not have actually quote been looking at capacitors per se but he was developing the physics that we use to understand how capacitors work and then there's also inductors and these have a unit of Henry's and again that's named after person and we use capital H for Henry now the other objective here so that's our first objective is all those just being kind of familiar with some of the unit's we'll be using a guy obviously when we start looking at these we'll talk about them a little bit more in detail the other thing in this lesson that we're looking at is we want to look at engineering notation now as I said at the beginning of this list and this is very closely related to scientific notation which it really is just scientific notation with us one kind of extra thing that we have going on here basically scientific notation we probably understand why we do say I'll just give a quick example so for instance a capacitor might have a capacitance of zero point zero zero zero zero zero zero zero one two ferrets and of course writing this down is zero point zero zero I mean that that's a pain to write that down every single time with all those things there's a couple reasons one it takes a long time to write but then also you can't lose the decimal point and then getting a real sense of you know what this is it's gonna be dealing with a small number and then the other thing is is we might at the same time be dealing with something that is for instance a resistor that is three hundred and thirty thousand ohms so we might be dealing with these kinds of things here and computations and so instead of having to always write out these large numbers we use scientific notation to of course make them a little bit more compact so if we just went to scientific notation we should all be familiar with this we kind of move this decimal point over and I'm just kind of showing and you move it over to that spot and so you have one two three four five six seven eight so this would be the same thing as 1.2 times 10 to the negative eight ferrets and then if we did scientific notation for this one here we'd move the decimal point because the decimal points right here and we go back this direction so one two three four five and so this would be equal to three point three times ten to the fifth ohms now that's all well and good too and I mean those are correct numbers as far as written with scientific notation but an engineering we're like well that's even kind of a pain to always have to be writing times ten to the negative eight or something so in engineering what we said it's like okay we're going to use prefixes to represent times 10 and I'll say to the N power because it could be any n power now you're probably used to this because you've probably seen things of course like centimeters which this is basically times 10 to the negative 2 meters and so instead of writing times 2 to the negative 10 we just would write centimeters now the thing with engineering notation is we always go engineering notation is always in powers of three so for example here let me just make a small table so it's not going to be necessary every single thing but it's going to be the most common ones and so I'll have the scientific and then the prefix that we attached to the unit I guess I didn't need that third branch there so what we do is I said powers at ten so I'm going to times 10 to the negative 15th which honestly we don't use that one too much but I'll still include it in our table oops I skipped negative six there and we could go even further but when we go to the positive exponents we don't typically encounter something much bigger than times ten to the ninth and so the prefix here four times ten to the negative fifteenth is something called femto and actually this is I'll get use this comm column just to write the thing down here so this is just a lowercase F times 10 to the negative 12 is Pico so this is just a P times 10 to the negative ninth is nano so this would be an N and then this is micro which is the Greek letter mu and then this is Milla or milli which is a lowercase M and then the base is just like the base unit so there is no prefix so that would be like meter or in our case like you know farad home things of that nature and then in this case times 10 to the third would be kilo which is lowercase K this is when we have to be a little bit careful with times 10 to the negative 6 is mega which is a capital M not to be obviously confused with the lowercase M and text that's obviously easy to pick up but in handwriting you need to be careful when you're doing handwritten things to make sure you know whether you're referring to milli or mega make sure that your capitals and lower cases are very distinct and then times 10 to the ninth is Giga and that is a capital G and now you could go further on like tera and stuff like that but we don't typically have to use those so to finish this video off let's go back to these examples here so let me first just what I'm gonna do is just last of that copy put that away copy and paste this down here so we can just look at this example again so you'll notice here that with engineering notation we always go on powers of three so if you're thinking about how you'd convert this here you would want to make sure that you do these in powers of three here and what you want to do is you could rewrite these here and so I'm gonna erase some of this here I'll go erase this little and so instead of going all the way up to five what we do here is we'd say okay we do a power of three and you always kind of want to do the power of three that's gonna be the quote best suited so I'm gonna go only that's three spots and I'm gonna go right there and so this would be equivalent to three hundred and thirty times ten to the third ohms which is the same thing if we use the engineering notation as three hundred and thirty kilometres zero point three three mega ohms now we typically especially with resistances don't write them as like 0.33 mega ohms we would write it as three hundred and thirty kilometres ear 0.33 for that it's not that this point three three mega ohms is wrong it's just not the standard way we typically write it now with this capacitor here what we do is okay we're at negative eight and if I look at this again here if I had gone one two three that's still gonna give me way too many zeroes another power four five six I could write it like that but let's do three more one two three so that's now nine so this is the same thing as twelve times 10 to the negative ninth ferrets which is the same thing as 12 nano ferrets and of course you could also write this again I'm not going to show the work for this but you should verify that this is also correct you could write this as 0.01 to microfarads however I'll box these here these are the two that would be the what we'd kind of say is the standard way of writing these here and so what you need to become familiar with here is this table of component we're going to be using these prefixes throughout the course now you'll get used to them just as we use them and then you'll also when you're doing computations of course when you're entering this in your calculator you would want to make sure to use the correct scientific notation when entering it into your calculator to do a computation all right so we're going to end the video here