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  • Hi. Why do we ever use AC to power homes instead of DC?

  • Haven't I showed you that AC is typically more dangerous than DC?

  • [Painful Gurgle]

  • Can we run everything on DC?

  • Yes! In fact pretty much every device at home has to rectify AC into DC

  • first before it can use it so why? Why am I angry?

  • The reason is elementary. Once there was a fight between a guy named Nikola Tesla being AC and Thomas Edison

  • being DC and Tesla won the contract on his employer Westinghouse company to provide power with AC

  • no matter how hard Thomas Edison tried to expose the dangerous nature of AC by

  • electrocuting dogs and elephants in public.

  • Wow

  • Now I remember why I'm angry; this Edison guy was an animal! He even invented the electric chair to execute with AC

  • --not because it was a cleaner or better way to execute--because he wanted to deface AC by forever associating it with death.

  • Nikola Tesla very rightfully won this battle.

  • Yes, AC can be more dangerous than the same level DC but a higher level DC can be as dangerous

  • if not more and just because something is dangerous

  • we don't stop using them like for example if you live in a high-rise

  • you are not in a constant risk of jumping off the window. But is there an advantage of using AC?

  • I mean, back then all they wanted was light using incandescent lights and those don't care about AC or DC.

  • Here I'm running a regular light bulb on AC as usual

  • and here I

  • S**t

  • S**t

  • I killed it.

  • Don't short s**t.

  • Anyways with this I'm converting the AC into DC using

  • It's a single diode, but it will do and if I measure the voltage at the output

  • F**k

  • S**t

  • Holy f**k the capacitor

  • Ah f**k

  • F**king piece of s**t

  • Anyways i'm reading around

  • 170 volt DC and although it's still quite dangerous

  • I can still touch it and it's not as remotely as painful as touching the 120 volt AC

  • and the lightbulb

  • Runs on it just fine

  • And it's even a little brighter because it's 170 volt continues

  • Beside the lights the electric motors were becoming more popular in home

  • Appliances like meat grinders or fans and such, but even those could be made into brushless

  • AC or brushed DC for example, of course a brushless AC motor like this one that I took from an old

  • microwave oven can last much longer than a brushed DC...

  • (S***,F***)

  • Loose wires, avoid them anyways brushes in DC brushed motors wear out eventually

  • And that's why AC motors can last longer, but beside that fact there doesn't seem to be much preference between AC and DC

  • But the real advantage of AC is not at home

  • It's before electricity even gets to home in transmission lines

  • And that's why Edison's DC power distribution system eventually died away, here

  • I made a transmission line using thin wires and using my supply

  • I'll try to place 10 volts across my 1 ohm load for 10 amps of current

  • And I'm measuring the voltage across my load. Let's try it

  • See the voltage is like

  • seven and a half and you see my

  • Transmission line is starting to smoke and heat up and the voltage continues to drop see the line resistance is so much that the voltage

  • Across the load doesn't even get to ten volts

  • It's at seven volts for seven amps through the load and because of the high resistance. It's heating up so much

  • Similarly because Edison was passing low voltage across the transmission lines a ton of current was passing through the lines

  • And there is a limitation to how thick you can make the wires before they break under their own weight or become too expensive

  • Huge currents through the resistance of the wire would result in large voltage drops over longer distances

  • And that's why Edison's system could only transmit power to around a mile or two from the power source

  • Otherwise the power loss would be so much over the lines

  • That would cause huge inefficiency, of course Edison was aware of his s**tty system

  • So he decided to let one of his genius employees to take care of the problem, who was our beloved Nikola Tesla

  • He was working for Edison at the time. according to Tesla Edison promised him

  • $50,000 which was a lot of money back then, if Tesla was able to make great improvements to Edison's DC system

  • Which Tesla did in a few months and when he went to Edison to ask for the money?

  • He said "Haha. I was joking obviously you're not aware of our

  • American humor," which Tesla said "F*** you, I quit !!!"

  • Later Tesla came up with his genius system and developed it for Westinghouse company

  • What he did was to transmit power much smarter. He used AC so he could change the voltage level using transformers, here

  • I'll use my auto transformer to generate 10 volt AC which would result in 10 amp AC through my 1 ohm load

  • But before I send it through the transmission line, first

  • I'll step the voltage up using my microwave transformer

  • and then I would step the voltage down after the line if I had a transformer

  • Well, guess I can borrow the one from our microwave

  • F**k. They're using tamper proof screws to stop me

  • What they don't know is that nothing can stop me. They are just postponing the inevitable

  • There we are...

  • I'll just take a picture of the wiring before I pull it out. I don't want to blow it up later

  • There we are

  • Ok, now we have both transformers connected. Let's do some voltage measurements before I connect the load. At the input

  • We have close to 10 volts so that's good. On the transmission line

  • We get around 190-200 volts. And at the output

  • Again we have close to 10 volts so that's pretty good. Now, let's connect a load

  • Ok. And the voltage across the load is

  • 1.6 volts? That's garbage. What happened? The transmission line voltage

  • 118 volts? Everything dropped

  • This is worse than the DC system. What's going on Tesla? Let's measure the transformer secondary winding resistance

  • Around hundred ohms. No wonder

  • There's too much drop over the large resistance of the secondary, so these transformers are not made for this purpose

  • That was a bad example. It doesn't matter. I'm gonna transmit power. No matter what

  • 2 volts. 3 volts

  • 4. 5. 6. 7

  • 8. 9

  • And 10 volts across the load. We did it

  • And our transmission line is not burning so that's always a plus

  • Nothing is exploding. What is the transmission line voltage now?

  • 820 volts!!! Well anyways, although

  • This is a pretty bad example, you can see that

  • I'm transmitting more power than the DC system

  • But my transmission lines are not burning. So, that's sort of a success?

  • See in this system

  • I can transmit a lot of power in this case around hundred watts without having to thicken the transmission line wires

  • And if the Transformers were better the efficiency would be higher, too

  • In fact, in this system, the higher you convert the voltage to, the easier it is to transmit power over greater

  • distances, with some limitations, of course. That's why in real life, they convert it to 10 kilovolt or hundred kilovolts

  • Why? Because in transformers, the input and output power is

  • ideally the same, although not really, because there's always some power loss as you saw, and power is voltage times current

  • So, for example, if I increase the voltage by

  • 20 times, in order to have the same power, the current has to drop by 20 times at the output of the

  • transformer and over the transmission lines. And because the power through a resistor is equal to resistance times current squared

  • The power would be 400 times less wasted on f**king wires

  • F**k

  • And with high voltage comes great responsibility

  • The transmission lines have to be placed far enough so no arcing happens

  • There is no easy way to do the same thing with Edison's stupid

  • DC system. In order to change the voltage, you would have to convert DC to AC,

  • increase the voltage, and then convert the AC back to DC, and lose a lot of power in the process

  • Edison still couldn't see this. All he saw was that his company was losing the contract of his life to power the world

  • So all he did was to grab the fact that

  • Tesla's system was running on super high voltage, like 10 kilovolt or 100 kilovolt, and say that it's super dangerous to people

  • by electrocuting animals with 10 kilovolt in public

  • Thomas Edison. He contributed a lot to science and technology what he was also an a$$hole

  • businessman, and that bit him in the lower back area

  • the moral of the story, don't be an a$$hole

  • GIVEAWAY TIME!!!

  • You know, CircuitSpecialists has been quite nice to me providing all my basic tools and components and everything

  • And I really hope you find what you need In their website too

  • And, I'm quite happy with the multimeter they sent me, which is an LCR meter. It measures inductance, capacitance

  • resistance, voltage, current, and a bunch of more stuff. So thanks to CircuitSpecialists

  • I'm gonna give away five of these to my patrons at patreon.com

  • and you the viewers. Also, if you want to start electronics you would need a lab power supply

  • And I'll give away four of those too. As usual, my patrons are automatically in the draw. For everyone else

  • please follow the link to the Google Form in video description and let me know which one you need and I'll draw your name

  • and that's it. Unibrow out

Hi. Why do we ever use AC to power homes instead of DC?

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Why Use AC Instead of DC at Home??

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    施廷叡 に公開 2021 年 07 月 18 日
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