Why do LEDs generate heat?

[whisky-dave]

I do in fact most products have LEDs that aren;t directly connected to mains voltages. Think or all the LEDS in a TV screen 1000s of them, and in phones. How about car headlights ?

[whisky-dave]

It's still a strip light.

[Commander Kinsey]

So what do washing machines use, AC or DC?

Does the current flow one way or both?

I thought I'd try to find out a typical power factor for a domestic street, so I checked

it doesn't have power factor measured, I was interested to see that at the current time (3pm Wed 9th Oct 2019), wind power is generated one THIRD of the UK's usage. I thought renewables were pitiful....

Any idea where I can find out what a typical home's power factor is nowadays?

[whisky-dave]

Water and some sort of cleaning chemicals dependent on personal choice.

I'm guessing it flows the way it wants, usually from a hight potentail differnce to a lower potential differnce. Depending on whther you are talking about real current or conventail current.

I thought you claimed you could measure it.

[AlexK]

It isnt that black and white with the more fancy motors used in the best washing machine designs.

That's not what determines if its AC or DC.

That doesn't show that for domestic streets.

Only real way to do that would be to measure it and its unlikely that anyone does that much.

You can turn that off and it isnt an email, it's a usenet post.

[Commander Kinsey]

Yes it is. For example a pulse width modulated voltage, which is only either 0V or 12V, is still DC. It's not a steady DC, but the current's only traveling one way.

I thought power companies liked to know these things for transmission line efficiency - hence business are charged extra for a bad PF.

New computer and I forgot.

Tell AVG that.

[AlexK]

No it isnt.

Its still DC when the direction of the current changes with an agitating direct drive top loading washing machine.

Not with an agitating direct drive top loading washing machine.

They don't bother with houses. Just accept the fact that its never going to be 1.

But houses don't.

They arent interested.

[Max Demian]

A few years ago Which? reviewed a washing machine that didn't use detergent: it sort of passed an electric current through the water. I don't know how good it was: apparently washing normally with detergent uses some kind of electric charge to clean fabric as just passing the water through the fibres isn't enough to remove the dirt.

[Commander Kinsey]

Do you have a link? Google ain't working.

[Max Demian]

For the latter, I was thinking of the following - click on "show transcript":

Not electrical, as I (mis)remembered: The detergent (presumably - it doesn't actually say) loosens the dirt in the tiny channels in the fabric, then, when rinsing in clean water, the detergent diffuses out taking the dirt with it. So it's the rinsing that removes the dirt: it's not just to remove the detergent.

I can't find a reference to Which?'s "electric washing machine." It was some years ago.

[whisky-dave]

Isn't that similar to how ultrasonic cleaners worked in that the molecules of water vibrated and dislodged the dirt, they were used for some circuit boards but mainly for jewlery, Maplin had one for sale years back.

[Bob Eager]

Actually, microscopic bubbles. And they are still around. Mine works well

- got it from CPC.

[Commander Kinsey]

I wasn't aware they'd stopped being used. I'm sure I've seen them for sale in the last year or 3. There isn't anything easier to use.

[Commander Kinsey]

But what does power factor mean in those circumstances? The only thing that matters is the power factor presented to the mains supply, on the other side of the LED power circuitry.

[Commander Kinsey]

In shape perhaps, but not worthy of being called "1970s".

[Commander Kinsey]

I guess it depends for how long it flows each way. If it's required to change direction for the motor to work, it's AC.

How come expensive power supplies intended for gaming enthusiasts have good power factor? They're only going to be connected to a domestic supply.

Well don't tell me because I can't change the way AVG works.

[whisky-dave]

Little to the user, but the designer would be interested.

which could depend on teh rest of the circuit.

whatever that means, do you know.

[Commander Kinsey]

Did you not understand the question?

That was the least useful answer I've ever seen.

But how do I know I have a typical home? An average is better - some people might have lots of motors and others lots of electronics. For an accurate result it would need to be measured across many houses.

[Commander Kinsey]

This amused me!

"But there?s another surprising advantage of not making lots of fur. Fur is made from proteins. If you?re not putting your protein into fur, well, you can use it to bulk up your brain. Maybe losing our body fur made us into the clever folk we are today."

So I was right, hairy folk are Neanderthal fuckwits.

This diffusion thing is simpler than people make out. You don't have to think of a gradient or wonder why it would magically follow it. If you have one area containing 50 things, and another area also containing 50 things, chances are the same amount of things will randomly move both ways. That's 50 pieces of muck still in the clothes and 50 pieces loose in the washing machine water. But if you have one area with 50 things and one with 0 things (that's clean water you've just replaced), no muck can move back in, it can only go out, until it reaches the equilibrium of 25/25. Or if the water outside the clothes is bigger than the clothes, an even better proportion.

[whisky-dave]

Yes and my answer made as much sense as the question.

you mean you didn't understand it. I thought you claimed to have a degree in physics yet yuo don;t know about conventail, current flow and actual flow which is in the oppersite direction.

How does anyone know.

and cultures.