Electronics question (didn't know which forum!)

Soldato
Joined
27 Jun 2005
Posts
2,863
Location
Aberdeen, Scotland
Hi guys,

I have here 10 red 5v LEDs and an old phone charger socket that was broken... I want to use the phone charger to power these LEDs and make a light out of them!

The problem (i think) lies in the mA rating of the plug. It has a 5v (4.9v) output and the LEDs are 5v so kno problem there, I can connect them in parallel and have a pretty lamp.. however the plug says on it 450mA whereas I only want between 10-30mA going to the LEDs.

Is this a problem? Or does the mA amount not matter in this case? This is the one part of electronics I never bothered to check up on lol... Thanks guys!
 
Soldato
OP
Joined
27 Jun 2005
Posts
2,863
Location
Aberdeen, Scotland
lol thanks dudes :) both a useful and comical reply! best of both worlds...


well... here goeOSHE&G%B"N!&YT)%&YV"!EISAGT OBUAGRRRRGGGGHHH OIH MY GOD IT BURNSNRNFPSAIJSNFB N!H B(!"&%V!!&!!!1111111................................................
 
Soldato
Joined
11 Jun 2005
Posts
3,606
Location
Liverpool
:rolleyes: I would have thought you'd need current limiting resistors...

Also they may not work well in parallel unless they all turn on at exactly the same voltage, otherwise the one with the lowest threshold will turn on first and all the current will go through that. Look at the specification of the LED though to find the maximum current, typically the ones I use are rated at 500mA, but they only need around 2v.
 
Soldato
Joined
9 Dec 2003
Posts
6,204
Location
Gone......
<----- electronics technician

I've done almost exactly what you're describing MANY times. As said before, the wall wart rating is the MAXIMUM it can supply, the LED's will only take what they need.

It's like in your car. The battery has the capabillity of supplying 1000Amps at any one time (granted for only a VERY short time), but your car stereo only needs 15 Amps to run at full volume. If you turn on the stereo, does it explode due to 1000 Amps being put through it? Nope, because it only takes what it needs.....
 
Soldato
OP
Joined
27 Jun 2005
Posts
2,863
Location
Aberdeen, Scotland
lol i tried it with one LED and it works ! - i'm building the light now!

I don't really have anything to build it in haha so I'm trying to find something to make it out of!!

Right now - I'm toying with an old tennis ball tube and a small headphone's holder tthing - not great tbh haa
 
Back
Top Bottom