How electricity works. . . . animated

at the end of the 1800s Thomas Edison was already a really accomplished inventor wildly famous quite the showman hard-working brilliant and a brute-force tinkerer more than kind of a physicist and Nikola Tesla was a younger of a younger generation also brilliant also hard-working much more awkward not quite the showman fact he had a somewhat debilitating OCD he had a you know every time he walked or did anything he had to do it in factors of three so 27 steps nine steps and that kind of thing kind of an awkward fellow asexual and a bit of a geek Tesla comes over to America to work for Edison and he comes equipped with a letter from a common friend of theirs who says you need to hire this guy Tesla he's really good he's a Serbian he comes over he's not particularly wealthy the fact he's pretty much broke and he comes over and it was since Asher you know you can work for me so Tesla is continually trying to talk Edison into moving towards alternating current Tesla believes it's a better way to go Edison who owns all the patents on direct current prefers to ignore Tesla and at one point they're kind of conflicting styles come through ahead Edison is faced with an engineering problem says the Tesla look if you can fix this I'll give you $50,000 and keep in mind this is $50,000 in you know one hundred and twenty five years ago so it's like quite a bit of money and Tesla fixes the engineering problem and Edison says huh that's great and Tesla says where's my money and Edison says no it's not what I meant I just was saying like a figure of speech like I'll give you a million bucks and Tesla says well I know how that sounds like that didn't sound like what you said you said you really were gonna give me fifty thousand so Edison says you're fired and Tesla says you can't fire me I quit Tesla goes to digging ditches literally digging ditches to get by to scrape by with another company and Edison continues on his quest to become the utility company see Edison was a famous inventor but he was trying to make a kind of a transition that we've seen for instance Steve Jobs make from inventor to the kind of captain of industry so Edison wants to become the utility that provides electricity to the world not just the US but in in Europe as well Tesla works his way up the kind of ditch-digging world and it becomes clear after a year or so that to his superiors that he's someone that needs to be reckoned with he's a mind that needs to be harnessed and he's introduced to George Westinghouse that George Westinghouse from the Westinghouse corporation who had made his money as an inventor of an air brake for a locomotive so Tesla talks to Westinghouse he's like look we need to go alternating current and he explains the advantages and Westinghouse says let's do it and they go into competition with Edison who's busy supplying cities all over North America and Europe with the record now many times it's not just cities it could just be a building like in other words it wasn't necessarily an entire municipality that would sign a contract so this was part of Edison's vision was that there would be kind of local supply of electricity Tesla had a different vision he had something a little bit more remote that would supply entire regions so this went on and eventually eventually of course Tesla's alternating current won out and it wasn't like this happened in obscurity I mean this is bigger than Mac versus PC this was bigger than beta versus VHS the entire country was actually following these two figures and trying to figure out which one whose power would win now here's my question why did alternating power win if you think you have an idea you can hit pause and kind of formulate an answer but if you don't don't worry we're going to get to it go ahead and do number 52 number 52 reads for a residence a circuit includes four 100 watt lamps five 200 watt receptacles and 475 watt lamps a reads how many total watts are used in this circuit when fully loaded B reads given that the circuit is standard 120 volt what should the amperage for the circuit be assume a power factor of 1.0 go ahead and hit pause now talking about electricity as in so many areas of building science there's a water analogy although water and electricity really aren't friends in real life so you have the battery which produces the voltage of the pressure voltage is pressure and indeed during Edison's day they actually called voltage electrical pressure that voltage sends the electricity through wiring a conductor as current current is equivalent to like the pipe size the flow so and literally a bigger wire will carry more current and then it goes across a resistor a resistor can be in our case it can be a lamp lightbulb and there's a switch to when it's connected it connects a circuit electricity is the movement of free electrons in a medium and it's the movement part that makes the whole thing work it's not the electrons it's the movement of them so in the equivalent water analogy we have a pump we have a flow we have friction and we have a valve now the analogy isn't perfect because if we take out the resistor if we take out the light bulb in the electrical example the whole system becomes really unstable it starts to heat up really quickly it could cause electrocution or fire it's a short circuit if we take out the friction element in the pump it's still cusine are somewhat stable but anyhow it's a pretty good analogy and it can hold and so what we want to know is we want to say ok electricity is a movement of free electron so what kind of materials have a lot of free electrons and the answers metals now which metals have the most free electrons are the best conductors actually the best one is platinum second most let's the Platinum is kind of expensive let's go to second most well that's gold let's go down to third well third silver but eventually we kind of get to what's pretty close to a tie for fourth which is aluminum and copper now are we gonna use aluminum or copper in our wiring it generally depends on the price of aluminum and copper right now that's basically what determines it for a while we thought that we were using both and it occurred to us that aluminum develops a film when it's exposed to air and that film in some occasions can cause fire so we stopped using alumina and then after a while we said well I think I lumen him actually is okay so we started using aluminum again and then we said well you know the fires are starting again maybe aluminum is a problem so aluminum is still used but it only can be used by a qualified electrician regular folk lay folk who are working in electricity kind of on their own homes Neath used copper because copper doesn't develop that film but electricians know how to deal with that they also have a copper clad aluminum if if the price of aluminum is enough lower than copper and you don't want to work with the film so if we if we draw a battery here and we're going to have a positive and negative end of the battery the positive end is going to have more electrons more free electrons it's going to go through a conductor the conductor is often going to be wrapped in an insulator which is a material that has few free electrons like plastic and then it's going to go through a resistor like a light bulb which in our next section will start to call a lamp and it will come back to the negative side and this is direct current batteries run on direct current the electrons will move through the conductor it'll move across the resistor the light bulb the light bulb will light up and then it will return and eventually the pressure the voltage in the positive and negative ends of the battery will be even so there'll be no more potential that we no more kind of extra pressure and then the battery will be dead and if we recharge it it'll move the electrons back over to the positive side but if we don't the battery's dead and that's direct current now alternating current is a bit different in alternating current we're taking a power source we're moving it across the resistor and then back again back and forth back and forth back and forth in the US we move it back and forth 60 times per second in parts of Europe and parts of the Middle East it's 50 times per second that's why you need the adapter any help so let's take a look at the problem that we started number 52 for a residence a circuit includes four 100 watt lamps five 200 watt receptacles and for 75 watt lamps how many total watts are used in this circuit when fully loaded that's a pretty straightforward answer we'll take four times 100 watt lamps is four hundred five times 200 watt receptacles is another thousand and four times 75 watt lamps is again three hundred so we'll add one thousand to four hundred to three hundred we get seventeen hundred watts seventeen hundred watts now to do Part B you actually need to know Ohm's law Part B says given that the circuit is a standard 120 volt that's what comes out of the wall in our buildings in the US what should the current amperage be for the circuit and assume a power factor of 1 well Elmo's law looks like this W which is the power as measured in watts equals AI which is the current as measured in amps times V which is the voltage which is like the pressure which is measured in volts so watts is like a gallons per minute coming out of the hose and I the current measured in amps is like the size of the hose and V the voltage measured in volts is the pressure in the hose and so again we want to understand the relationship of the math if we double the amperage if we increase the pipe size if we increase the amps what are we doing if we double it what are what are we doing to the watts we're doubling it if we double the voltage we're also doubling the watts if we double the voltage and double the amps we're doubling both so using that formula we say okay 1700 watts equals some current times a known voltage our standard 120 volts coming from the socket and we solve for that and we divide 1,700 by 120 and we get an amperage of 14 point two amps now we can look at a chart and we can now amps member is like the pipe size so we can look at a chart and the chart will say that a 15 amp circuit uses a number 14 gauge wire and the actual size is about a sixteenth of an inch and a 20 amp circuit requires a number 12 gauge wire remember a metal as we go lower in number in gauge we get thicker and the actual size is a little bit bigger at 0.8 inches and this goes all the way up to 200 amps and around 200 amps our conductor size is called double knot zero zero and it's about a third of an inch so as we get more and more current we need a bigger and bigger wire now here's the problem big wires high amperage circuits over long distances they get hot and they leak their electricity to electromagnetism that'll be important later so let's say that for the town that you're in or the neighborhood you're in maybe it requires a million watts 1 million watts so given that at 120 volts how many amps that we need to supply 1 million watts so you have 120 volts you have a million watts how many amps do we need go go ahead hit pause so running out the math we have 1 million watts equals some current times our pressure of 120 volts now solving for amps we get 8333 amps here's the problem if we want to supply 8333 amps well look if 15 amp is about a sixteenth of an inch and 200 amp is about a third of an inch our telephone poles to supply your neighborhood or your city to supply that 1 million watts at 120 volts you'd have like cables of the diameter of school buses being strung from pole to pole and that makes no sense we can't do that first of all it's too heavy second of all it's too expensive to do and third of all we can't run long distances on high amperage we already said that if it's a big pipe we can't run a long distance it gets too hot and it leaks too much electricity on the way so we got to figure out a better way to do it now we could just supply it at a higher voltage so let's figure it out now let's do a million watts at 60,000 volts now what's the new amperage going to be so to figure out the new amperage and we'll divide both sides by 60,000 and we'll find out that the new amperage is about sixteen point seven perfect so what we'll do is we'll just run 60,000 volts at sixteen point seven amps that works out so we can just run the 60,000 volts right to be outlet why can't we run the 60,000 volts right to the outlet well because we'd have lightning from the socket we wouldn't even be able to get close to an outlet without getting electrified see if you take a nine volt battery and you stick your finger across both poles in the battery your finger doesn't have enough free electrons to be moved by the nine volts in the battery there's not enough voltage but if you stick your finger you know in a socket there's enough voltage there at 120 volts there's enough pressure there's enough pressure to push the electrons across your finger so there's always this relationship between higher voltage is more pressure and it allows and like I said in Edison's day there used to call it electrical pressure and it allows the electrons to jump farther because it's under higher pressure and you can look at this image to get a sense you have the vault kind of pushing the amp through and the ohm which is a resistance which we haven't talked about too much is kind of crimping it down but the more voltage the more pressure so there's always this kind of balance on the one hand we want really high voltages to run long distances to run power long distances but on the other hand we went really low voltages to make sure we don't get electrocuted in our buildings and make sure it fires don't start keep property safe keep equipment safe so how do we do this well this is the crux of why Tesla won and Edison lost because when you run high voltages you need to be able to step them down so what we'll do is we'll start at the power plant and we'll produce say 60,000 volts now it could be as high as over 700,000 volts it could be something like 30,000 volts but we have these regional feeders these high voltage transmission lines they kind of look like giant erector sets and they dot the landscape they're really really tall high off the air of course they're high off the ground because we don't want the voltage the voltage is so high we don't want the power to arc because then the power lines I think we always think of them as wrapped in an insulator but they're not they're live they're totally live and the electrons are moving through them and really want to go to the ground so if you get close enough it'll jump out and it'll kind of meet its it'll meet something else that touches the ground now birds can rest on these no problem because they're not touching the ground the birds don't possess the best path for the electrons to go through so if a bird was in theory actually it happened to a squirrel sometimes so if the squirrel is in theory the tip of his tail is touching the hot wire and his nose is touching the pole that supports it the squirrel will get zapped because he's produced now a better path for the electrons to move to the ground anyhow they're going to move across the country at tens of thousands sometimes hundreds of thousands of volts from the power plant then they're going to go to these power substations now in cities these are generally out of view but in in most of America you see these kind of everywhere they're usually about a you know half a block big or quarter block big they have gravel everything is painted a certain color gray they're fenced in with barbed wire because they don't want people jumping them and there every I don't know so many miles is one of them and what the job of that power substation is to do is to step down the voltage to take it from in our example 60,000 volts down to in our example 12,000 volts now 12,000 volts is still plenty of voltage way it's still unsafe but it's not so unsafe that it can't run underground around the city it's not so unsafe that it can't run on wooden poles around the city so it'll go on wooden poles that maybe 12,000 volts although the number could be different it could be 3000 it could be 15,000 and it will go around until it hits the buildings and once it hits the buildings there's another transformer again the transformer steps down the voltage so the voltage will be stepped down to 120 volts before it goes into your building then it goes into your building at 120 volts and it comes out the outlet at that much safer voltage level now here's why Tesla won and here's why Edison lost at least at the time we didn't have the equipment to step down voltage we didn't have transformers that worked with direct current we only had it with alternating current which meant that this kind of trade-off when were taking power around the country at high voltages and stepping it down to lower voltages that system didn't work in Edison's world in Edison's world the power plant would be there be a power plant every few blocks that power plant would generally be a small generator and it would be supplying the buildings around it then another few blocks would be another generator because we couldn't take the record too far because if we took it too far we need too much wattage if we need too much wattage we need bigger pipes we need more amperage if we need more amperage over long distances we have too much heat buildup and too much electricity lost to electromagnetism in the in the transmission so in Edison's model it was a distributed model where there were power plants kind of everywhere and you could see why Tesla's model was superior at the time because

Channel: Amber Book

Views: 3,710,902

Rating: 4.1742902 out of 5

Keywords: electricity, power, conductor, insulator, wires, current, amps, volts, voltage, watts, direct current, alternating current, electrons, resistor, tesla, edison, westinghouse, ohm's law, energy, Nikola Tesla (Inventor), Thomas Edison (Inventor), 60 hertz, 60 hz, 50 hz, 50 hertz

Id: ZInLPe_bezQ

Length: 19min 25sec (1165 seconds)

Published: Thu Oct 30 2014

Reddit Comments

[u/keylocksmith]

Because?

[u/Lukecv1]

That video sucked. Hardly anything was animated