Why PSUs are better at 220V?

[Murilo_A]

PSUs work better running at 220V, but why? I know the waste less energy and produces less heat, but I didn't found anything telling why that happens.

[ARikozuM]

@STRMfrmXMN @Energycore

ASSEMBLE!

 

With their powers combined, they are... an Ampharos and a Zapdos?

[Mr.Meerkat]

It's due to current. Lower voltage=higher current required to achieve the same amount of power and same goes for higher voltage=lower current required to achieve the same amount of power. 

For example, voltage isn't the thing that kills people most of the time but current is, which can be seen by how there's more fatal accidents in countries that uses 100-120V compared to countries that uses  220-250V.

[Joe_MacDougall]

2 minutes ago, Mr.Meerkat said:

It's due to current. Lower voltage=higher current required to achieve the same amount of power and same goes for higher voltage=lower current required to achieve the same amount of power. 

For example, voltage isn't the thing that kills people most of the time but current is, which can be seen by how there's more fatal accidents in countries that uses 100-120V compared to countries that uses  220-250V.

That would make sense. Most people have about 18000V of static electricity on them most of the time.

[Energycore]

21 minutes ago, Mr.Meerkat said:

It's due to current. Lower voltage=higher current required to achieve the same amount of power and same goes for higher voltage=lower current required to achieve the same amount of power. 

For example, voltage isn't the thing that kills people most of the time but current is, which can be seen by how there's more fatal accidents in countries that uses 100-120V compared to countries that uses  220-250V.

 

22 minutes ago, ARikozuM said:

@STRMfrmXMN @Energycore

ASSEMBLE!

 

With their powers combined, they are... an Ampharos and a Zapdos?

Let the math begin!

By Ohm's law: I (current) = V/R

 

Since efficiency is basically the opposite of resistance, I'll call that E = 1/(R+1), so that as R approaches 0, E approaches 1 (or 100%) and as R grows, E approaches zero.

Thus R = 1/E - 1

 

What we're trying to model here is the change of E with respect to V while keeping the amount of power constant, so we'll have to introduce W=VI as our measure of power in Watts.

 

From Ohm's law,

RI = V

.: RIV = V^2

.: RW = V^2

.: W = V^2/R

 

Given that W is constant, we can see here that as V increases, R decreases, and thus E would increase, which is what I wanted to prove.

 

Notice that these equations require R to be nonzero. It is unclear to me whether a material would actually manage zero resistance IRL, but if there is one, this model does not work for it. Thankfully the materials used in everyday circuits all have nonzero resistance.

[ARikozuM]

1 minute ago, wrathoftheturkey said:

Thankfully? More efficiency is bad?

I'm guessing that no resistance would mean no potential to change the current, but I'm just a veterinarian. #NotEngineer

[Energycore]

1 minute ago, wrathoftheturkey said:

Thankfully? More efficiency is bad?

Thankfully because if a material did, that model doesn't work for it

 

I guess you could use calculus to adapt that model

[Energycore]

Just now, ARikozuM said:

I'm guessing that no resistance would mean no potential to change the current, but I'm just a veterinarian. #NotEngineer

Also #notengineer

[Energycore]

Just now, wrathoftheturkey said:

Was a joke lol. Edited in the /s but guess you were faster. Your math seems solid though

 

This is like, middle school stuff. Well, more like middle school Science Olympiad stuff, but yeah

Dammit now I'm also stereotypically nerd in that I didn't pick up on a social cue.

 

Fuck.

[Mira Yurizaki]

There's also the fact that all power supplies internally run on 230V. There's a voltage doubler in front of of the rest of the circuit for 115V inputs.

 

But that may not be the main reason.

[Energycore]

Just now, M.Yurizaki said:

There's also the fact that all power supplies internally run on 230V. There's a voltage doubler in front of of the rest of the circuit for 115V inputs.

 

But that may not be the main reason.

Oh interesting

[Mira Yurizaki]

Just now, Energycore said:

Oh interesting

Probably for the reasons you proved.

 

Though the voltage doubler bit is half true. It's only there for PSUs with a physical switch. If it uses active PFC, then the way it works allows it to generate 230V regardless of input.

[STRMfrmXMN]

1 hour ago, ARikozuM said:

@STRMfrmXMN @Energycore

ASSEMBLE!

 

With their powers combined, they are... an Ampharos and a Zapdos?

Ya know what's funny is I had no fucking clue until @Energycorewrote a novel about it.

 

50 minutes ago, Energycore said:

 

Let the math begin!

By Ohm's law: I (current) = V/R

 

Since efficiency is basically the opposite of resistance, I'll call that E = 1/(R+1), so that as R approaches 0, E approaches 1 (or 100%) and as R grows, E approaches zero.

Thus R = 1/E - 1

 

What we're trying to model here is the change of E with respect to V while keeping the amount of power constant, so we'll have to introduce W=VI as our measure of power in Watts.

 

From Ohm's law,

RI = V

.: RIV = V^2

.: RW = V^2

.: W = V^2/R

 

Given that W is constant, we can see here that as V increases, R decreases, and thus E would increase, which is what I wanted to prove.

 

Notice that these equations require R to be nonzero. It is unclear to me whether a material would actually manage zero resistance IRL, but if there is one, this model does not work for it. Thankfully the materials used in everyday circuits all have nonzero resistance.

 

[Energycore]

Just now, STRMfrmXMN said:

Ya know what's funny is I had no fucking clue until @Energycorewrote a novel about it.

 

 

Actually I had no fucking idea before writing that novel, but I had this hunch that I could prove it so I did

[vanished]

2 hours ago, Energycore said:

Notice that these equations require R to be nonzero. It is unclear to me whether a material would actually manage zero resistance IRL, but if there is one, this model does not work for it. Thankfully the materials used in everyday circuits all have nonzero resistance.

It is theoretically possible to create a substance with 0 resistance.  They're called super conductors, and it usually occurs at very cold (think -150 C or colder) temperatures.  The real fun comes when you short-circuit a battery through a super conductor, since you cause the universe to divide by zero irl (due to the way resistance factors into equations), which, I assume, creates a black hole.  

[Godlygamer23]

3 hours ago, Mr.Meerkat said:

For example, voltage isn't the thing that kills people most of the time[.]

Voltage will never kill people. It's always the current behind it. People will bring in resistance, and even say "well, the high voltage caused the current to arch over," but it's always the actual electrical particles doing the damage, never the voltage or resistance of a particular body.

 

Case in point that voltage cannot kill or harm people? Static electricity. The voltage can be as high as 20,000V, but the amount of actual current is so low that it doesn't affect us. Add enough current, and you get something very damaging.

[Energycore]

2 minutes ago, Ryan_Vickers said:

It is theoretically possible to create a substance with 0 resistance.  They're called super conductors, and it usually occurs at very cold (think -150 C or colder) temperatures.  The real fun comes when you short-circuit a battery through a super conductor, since you cause the universe to divide by zero irl (due to the way resistance factors into equations), which, I assume, creates a black hole.

Lol I think that notion is puro fantasy.

 

You can't divide by zero IRL. Zero is a concept that only exists in the models we create to explain the world around us. What I would say is, the model of Ohm's law doesn't work for superconductors, because it requires the resistance value to be nonzero.

 

The whole idea that dividing by zero IRL would collapse the universe, I've a feeling comes from this proof from field theory:

 

Quote

Let F be a field with + and * its operations. (Any field must have at least an element that's null by sum, or "0", and an element that's null by product, or "1", and they must be nonequal).

Let k be a number in F such that 1/0 = k. It is equivalent to say that 0*k = 1

 

Thus k*0* k = 1*k = k

Since k*0=0 for all k in F,

Thus k*0 = k

Thus 0 = k

Now as you might have concluded, this is nonsense, because the elements "0" and "1" of a Field must be nonequal, but what this proof also shows is that if you were to find the result of dividing by zero, all numbers in your field (say, the field of real numbers) would "collapse" to zero. If we assigned a number to each point in the universe, then I guess dividing by zero IRL would collapse the entire universe into the point that you had assigned to the number zero.

[vanished]

2 hours ago, Energycore said:

Lol I think that notion is puro fantasy.

 

You can't divide by zero IRL. Zero is a concept that only exists in the models we create to explain the world around us. What I would say is, the model of Ohm's law doesn't work for superconductors, because it requires the resistance value to be nonzero.

 

The whole idea that dividing by zero IRL would collapse the universe, I've a feeling comes from this proof from field theory:

 

Now as you might have concluded, this is nonsense, because the elements "0" and "1" of a Field must be nonequal, but what this proof also shows is that if you were to find the result of dividing by zero, all numbers in your field (say, the field of real numbers) would "collapse" to zero. If we assigned a number to each point in the universe, then I guess dividing by zero IRL would collapse the entire universe into the point that you had assigned to the number zero.

Yeah the first half of what I said was true but the rest was a joke  

[Energycore]

1 minute ago, Ryan_Vickers said:

Yeah the first half of what I said was true but the rest was a joke  

Dammit

[ARikozuM]

23 minutes ago, Energycore said:

Dammit

Is that twice in one day that you've missed out on a social cue?

[Energycore]

25 minutes ago, ARikozuM said:

Is that twice in one day that you've missed out on a social cue?

No?