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Would a LED short itself?

M

Mr. Man-wai Chang

Jan 1, 1970
0
Any professor/PhD level explanations? :)

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M

Mr. Man-wai Chang

Jan 1, 1970
0
It wouldn't. Someone would have to do something to it.

Is it nothing more than a light bulb?

Would you use a current-limiting resistor when you use traditional light
bulb? :)

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M

Mr. Man-wai Chang

Jan 1, 1970
0
It wouldn't. Someone would have to do something to it.

OK, are there 20mA fuses? Isn't a fuse safer than a resistor? :)

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M

Mr. Man-wai Chang

Jan 1, 1970
0
Would you use a current-limiting resistor when you use traditional light
bulb? :)

And a traditional light bulb could be powered by 110/220 V AC... isn't
it extremely dangerous not to use a current-limiting resistor? :)

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M

Mr. Man-wai Chang

Jan 1, 1970
0
It depends on the definition of "LED" >:-}

Tell me something I dunno! :)

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T

Tom Biasi

Jan 1, 1970
0
Is it nothing more than a light bulb?

Would you use a current-limiting resistor when you use traditional light
bulb? :)
An LED is not a light bulb, it's a diode. Light bulbs (as understood to
be incandescent by the tone of this conversation)are resistive and
designed to operate at certain voltages.
 
T

Tom Biasi

Jan 1, 1970
0
OK, are there 20mA fuses? Isn't a fuse safer than a resistor? :)
May I suggest that you examine the function of those two devices?
 
M

Michael Black

Jan 1, 1970
0
Is it nothing more than a light bulb?

Would you use a current-limiting resistor when you use traditional light
bulb? :)
I think you need the newsgroup that's even lower than basics.

An incandescent lightbulb uses a relatively high resistance wire, power
put through that wire causes it to light up. If that lightbulb goes bad,
it would generally open up. The only way it could short is if the
filament collapses on some of the lower wire in just the right way, but if
the bulb was on at the time, the power would just burn out the wire that
remained, too much current going through regular wire.

An LED is a solid state device. There may be instances when they might
short out, but generally they'd just expire, leaving an open circuit.

The resistor that all LEDs need (except for the LEDs that have some
current limiting inside the package) is because the LED is a current
device, it needs a certain amount of current to light up (so long as the
voltage is higher than it's threshold, and lower than the maximum it can
take). If too much current goes into the LED, it can "blow up". It is
different from an incandescent bulb.

Sometimes people do use resistors in series with incandescent bulbs. They
want to limit the current surge through the bulb before the resistance
goes up as it heats up. Or, to limit the actual light out of the bulb,
though there are better ways to do that.

Michael
 
M

Mr. Man-wai Chang

Jan 1, 1970
0
An LED is a solid state device. There may be instances when they might
short out, but generally they'd just expire, leaving an open circuit.

What exactly are those instances?

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M

Mr. Man-wai Chang

Jan 1, 1970
0
May I suggest that you examine the function of those two devices?

You meant I should use both a limiting resistor as well as a 20mA fuse? :)

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T

Tom Biasi

Jan 1, 1970
0
You meant I should use both a limiting resistor as well as a 20mA fuse? :)
No, I mean you should learn what those devices are for.
 
More of a Light Emitting Resistor (LER) isn't it? ;-)


Yes! I like it! Henceforth we must call all incandescent light bulbs Light Emitting Resistors!

Oh, wait, by that definition some electric space heaters would also qualify as Light Emitting Resistors, huh.
 
M

Mr. Man-wai Chang

Jan 1, 1970
0

Waste of my time...

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M

Mr. Man-wai Chang

Jan 1, 1970
0
So far, that part's been easy.

The difficult part seems to be getting you to understand some simple
concepts.

SO an LED could never be used as a light-emitting fuse?

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M

Mr. Man-wai Chang

Jan 1, 1970
0
FYI, the video could also waste your time. :)

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M

Mr. Man-wai Chang

Jan 1, 1970
0
How would you rate its fusing current?

By just applying 3V over the LED, it would draw whatever current needed?

Summarizing the replies from the answers, most said that the LED might
**NOT** always just blow like a fuse. And that's the main reason of
using a current-limiting resistor.

If LED would always die like a fuse without shorting itself, then there
should not be a need for a resistor.

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T

Tom Biasi

Jan 1, 1970
0
By just applying 3V over the LED, it would draw whatever current needed?

Summarizing the replies from the answers, most said that the LED might
**NOT** always just blow like a fuse. And that's the main reason of
using a current-limiting resistor.

If LED would always die like a fuse without shorting itself, then there
should not be a need for a resistor.
With all due respect this thread is going nowhere fast. You have
received enough information to realize that your logic is severely
flawed and that you need to do some research.
Now I'm suspecting troll activities.

Tom
 
M

Mr. Man-wai Chang

Jan 1, 1970
0
OK, let's end this thread! I will use current-limiting resistor. :)

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