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Old November 29th 14, 04:41 PM posted to rec.radio.amateur.homebrew,rec.radio.amateur.boatanchors
Rob[_8_] Rob[_8_] is offline
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First recorded activity by RadioBanter: Dec 2008
Posts: 375
Default High brightness LEDs?

Jerry Stuckle wrote:
Completely unrelated. The LED electronics and the power supply work
completely differently.


Maybe your power supply, but mine is a switchmode supply and it works
completely the same as any other. It is regulated for voltage, not for
current, but that is another matter.


Completely unrelated. The LED electronics and the power supply work
completely differently.

The first difference you are ignoring is your power supply is constant
voltage. A LED power supply is constant current. They work on entirely
different principles.


Constant voltage and constant current are not different principles.
Linear and switchmode are.

Sure they can be connected in series. But that has it's own problems;
you can only go so far. And yes, the LED gets a DC supply - but it's
the generation of the constant current source which causes the problems.


What problems?

Don't believe me, though. Look at some of the references I have posted
- all written by EEs intimately familiar with the technology.


When someone points you at a manufacturer that gets things right you
question the truth...

The mains here is 230V AC. There even are proposals to change that
into 325V DC or even 500V DC. Not accepted proposals with a set date,
but still. DC supply is more efficient for the home these days, now
everthing uses switchmode supplies, it can transport more power
with the same amount of copper and the same class of insulation.


That's fine for you. Personally, I don't expect it to get very far.
But it's not going to happen here.


Of course not. You are living in the USA. There is no innovation
in the USA. I would never expect something to be changed.

Back in the 1800's, there was a current war. Nikola Tesla (supported by
George Westinghouse) proposed using AC. Thomas Edison proposed using
DC. Both had their advantages and disadvantages. AC won, obviously.


At that time, AC had more advantages. Now, DC has.

And now, it is so ingrained into our economy there is no chance of changing.


The economy here works a bit differently. When new systems have
advantages, they get deployed. Especially when they consume less energy.
You know, we have (only) digital TV here. For nearly 10 years no.
Something that will take years in the USA.

Although the utilities are building some long distance DC transmission
lines.


There you are!
A DC transmission line between here and Norway has been operating for
several years. Windenergy parks at sea are also feeding DC.
But at home it is even more of an advantage. E.g. to charge your
electrical car you want as much power as possible, and at DC the same
copper wire with the same insulation and safety concerns can transport
2-4 times more power.