Why do LEDs generate heat?

Can't be bothered finding it, I don't believe in earthing anyway.

Reply to
Commander Kinsey
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They arent on the mains. They are driven by the electronics. Similar to the difference between a conventional transformered power supply and a modern switch mode power supply instead.

The other obvious way is to drive it with the electronics instead of having it on the mains. Most obviously with a stepper motor, although that isnt what is used in washing machines.

Yes, the early ones did, before power semiconductors were economically feasible for that sort of situation.

It's the death squad that has its orders, not you.

Reply to
AlexK

Lot easier not to have to.

Reply to
Max Demian

An acronym is a pronounceable abbreviation, e.g. NATO, scuba, radar.

Reply to
Max Demian

It only really matters if you are doing precise colour matching. Colour temperature of the incident natural light matters almost as much!

You have to have a material with very peculiar absorbtion band features before it makes any appreciable difference. A handful of minerals like Alexandrite and synthetics line didymium doped glass have an apparent colour to the human eye which depends critically on light quality.

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Although they don't output violet the mix of blue and red light is good enough. The eyes sensors are actually blue, green and yellow sensors. Red is computed in the brain as Y-G which is why didymium doped glass gives such an interesting effect with out of gamut cartoon colours. It puts a sharp notch into the yellow wavelengths perfect for glassblowing.

Reply to
Martin Brown
[snip]

In the case I described, the lamp (a "helpful" person tuned on) was to my side, almost the same direction as the back of the TV.

Reply to
Mark Lloyd
[snip]

Over-the-shoulder light would be a lot better than black letters on a very dark gray background (because your eyes are adapted to the bright light coming around the edges of the book).

Reply to
Mark Lloyd

I know they don't get driven directly from the mains, as they need to go different speeds. But are they DC or AC? since they can rotate either way, does that mean they have to be DC? Or can it be AC using different coils?

Depends what the electronics is as to whether it blocks the PF?

I think this one was from the 60s or earlier.

[facepalm]
Reply to
Commander Kinsey

I was just suggesting you could rectify that Marantz.

Reply to
Commander Kinsey

Ah, I always say acronym to mean abbreviation. I don't care if it's technically wrong :-)

Reply to
Commander Kinsey

So their power factor is no longer relevant to the mains.

It isnt the black and white with those. Same with universal motors.

Or driven differently. Is a stepper motor DC or AC ?

Its not blocking that matters, what matters in this context is what the mains sees of the entire appliance.

Yeah, could well be before power semis were economically viable in that price of appliance, particularly if you allow for quite a bit of inertia in how designs change over time etc.

Reply to
AlexK

I suspect there are several belts. I partly removed the transport mechanism and replaced it and it seemed to work better for a bit - I didn't see any belts. I'm re-recording my classical stuff from Freeview Radio 3 and converting it to MP3 currently.

Reply to
Max Demian

That depends on the statement yuo wish to make. If you want to test the power factor of an LED then that is what you test for. If you want to test the power factor of an PSU then that is what you test for. otherwise the test is pretty meaningless.

Reply to
whisky-dave

The lighting in all my rooms comes from striplights all over the ceiling, so everything is lit nice and evenly.

Reply to
Commander Kinsey

Explain.

I don't know. I've only used them briefly in radio control models, but not looked at the circuitry in great detail.

That's my point. Can PF be seen through a transformer or power supply?

Reply to
Commander Kinsey

Indeed, it's often easier to just download a new copy than to convert something from an old version you have on tape/LP/etc.

Reply to
Commander Kinsey

Universal motors run on AC or DC, that's where the name comes from.

You don't need to. You know the basics of how they are driven. The problem is with whether that is called AC or DC. Strictly speaking it isnt either.

No it cant with those fancy motors in washing machines etc now.

Reply to
AlexK

Is that really nice, sound more like yuo're living in a 1970s factory.

Reply to
whisky-dave

All we care about is the power factor of the whole unit. You don't have LEDs on their own.

Reply to
Commander Kinsey

They're little LED strips, they don't look like those huge ballast driven flickery fluorescents.

Reply to
Commander Kinsey

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