Is it possible to damage a LED by connecting it directly to a 9V battery?

[SteveB]

I just received some from violet & blue LEDs from Small Bear, & since they are all clear, I connected to a battery to see which ones were which. One lit up brightly, then dimmed down to nothing. Another one lit up brightly, then was dimmer each time I tried it again.

Did I mess up?

Thanks,
Steve

[foxfire]

yes, you killed it. next time try using a 4.7k resistor in front of the led. and watch it, i here they can explode.

[jonathan perez]

yes, 9 volts is alot of power for a LED. the blue ones burn the best.

[MetalGod]

I keep some dead'ish PP3 around for this very purpose - a dying PP3 still measuring about 5v is perfect for testing LEDs.

[Paul Marossy]

You bet! 9V will kill an LED lightning fast. Sometimes they'll even make a popping sound as they blow. 

[SteveB]

Thanks, guys. Live & learn.

Steve

[Mark Hammer]

I keep some dead'ish PP3 around for this very purpose - a dying PP3 still measuring about 5v is perfect for testing LEDs.

Me too.  If it doesn't tickle your tongue very much, it will be perfect for testing out an LED.

And BTW, it's not the voltage.  It's the current that fries the LED.  You could take a brand new car battery and power an LED if you wanted, so long as there is a suitable current limiting resistor between the battery and LED.

[moro]

You bet! 9V will kill an LED lightning fast. Sometimes they'll even make a popping sound as they blow. 

They smell funny too.

[kurtlives]

You bet! 9V will kill an LED lightning fast. Sometimes they'll even make a popping sound as they blow. 

Ya they can.

The other day I was blowing up LEDs with a power source. I had 30V running into the little suckers

[the_random_hero]

I've had 3mm and 5mm red LED's explode and send pieces of glass (or epoxy? I'm not sure but it was sharp as hell) flying through the air. If one of those suckers hit me, it would have caused quite a bit of damage.
Moral of the story? Don't let EE students in a prac room with no supervising teachers  Oh wait, I think it was that you should use a current limiting resistor...

[jayp5150]

They smell funny too.

You beat me to it lol. I had a violet one a couple weeks ago and I killed it with too low of a resistor. $3.50 blown (umm... literally, I guess lol).

[gez]

One of the funniest things I ever saw was when a Maplin sales assistant tested a LED by connecting it to a battery the size of a housebrick.  It lit up in a puff of smoke...and then so did he:  "*U£$*!!"  Whilst he tried to pry the burning skin of his fingers from the legs of the LED, I took the time to explain to him that the customer he was serving was right in saying that a resistor is needed to limit current.

Tough love...

[~arph]

They smell funny too.

You beat me to it lol. I had a violet one a couple weeks ago and I killed it with too low of a resistor. $3.50 blown (umm... literally, I guess lol).

$3,50 for a violet LED??  eeehm..  that ridiculously expensive even at this exchange rate.
http://cgi.ebay.com/ebaymotors/50X-5mm-ULTRA-VIOLET-UV-LED-LAMP-395nm-50-Resistor_W0QQcmdZViewItemQQcategoryZ33713QQihZ024QQitemZ370000296133QQrdZ1QQsspagenameZWDVW

[jayp5150]

They smell funny too.

You beat me to it lol. I had a violet one a couple weeks ago and I killed it with too low of a resistor. $3.50 blown (umm... literally, I guess lol).

$3,50 for a violet LED??  eeehm..  that ridiculously expensive even at this exchange rate.
http://cgi.ebay.com/ebaymotors/50X-5mm-ULTRA-VIOLET-UV-LED-LAMP-395nm-50-Resistor_W0QQcmdZViewItemQQcategoryZ33713QQihZ024QQitemZ370000296133QQrdZ1QQsspagenameZWDVW

Not a UV one, just a purple one. I picked it up at a local supplier (Parts Express). I just double-checked, it was $3.90 lol. No shipping though 

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=070-010

When I'm able to start buying stuff again, I need to check the ebay listings.

[Electric_Death]

yes, you killed it. next time try using a 4.7k resistor in front of the led. and watch it, i here they can explode.

Some years ago I got this giant LED, about the size of a marble.
While tinkering around with wires, resistors and pots, I cranked a pot wide open and KAPOW!
The shrapnel stung pretty good, I suspect you could actually use one as a detonator in a bomb.

[slideman82]

I think 6V is the max voltage a led can stand. Keep a wasted 9V battery (I have one, it's my official LED recogniser, with about 4V), if it has about 7V or more, just solder a bigger-than-470ohms resistor to one of the battery contacts.

[Paul Marossy]

They smell funny too.

Yeah, that's true. I forgot about that. It's been a while since I fried one... 

[~arph]

Not a UV one, just a purple one. I picked it up at a local supplier (Parts Express). I just double-checked, it was $3.90 lol. No shipping though 

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=070-010

When I'm able to start buying stuff again, I need to check the ebay listings.

Haha yeah, I made the same "mistake" too though.. live and learn.
(btw, they have all the colors you wish for on that ebaystore.. I just didn't spot a real purple one so fast   )

Cheers!

[sshrugg]

 

First time I did this, I was counting my fingers immediately after.

[head_spaz]

The site linked below has done a nice write up on various "purple" LEDs, measuring
and comparing the wavelengths, dispersion angles, etc... between various manufacturers
and suppliers.
It seems that the lower 395nm wavelength  (listed at the above ebay website) is a purer
purple, which makes sense because safe "blacklight UV-C" is actually 356nm. And everyone
knows blacklights are purple. (But stay away from 245nm UV-B, it will damage your eyes)
Lots of good info here...
http://ledmuseum.home.att.net/ledvio.htm

Hope this info is helpful.
Best Regards...