Anyone Know How To Wire In Leds ?

[smckeown 1]

I'm looking at replacing an existing warning lamp with a bright but small LED, and wire in a new LED. I read somewhere you need resistors ? and that's where i stopped

 

Can anyone who knows what they are doing help me out ?

 

I'm hoping/assuming I can buy the bits needed from somewhere like maplin

 

cheers

sean

[pugrallye 0]

yes you can need to find out the currant draw of the led first then you have to put a resistor in series and they are polarity sensitive, i think the flat side on the led is the cathode (negative) been many years since playing with LED's so sure someone else can confirm the pin's

[petert 586]

R=(V-1.7)/0.020

 

where R= series resistance

V= input voltage

 

The aim is to drop the input voltage to 1.7 volts with a current of 20mA. The flat side of the LED is negative. Don't get stressed if you get the polarity wrong, just reverse it.

[pugrallye 0]

R=(V-1.7)/0.020

 

where R= series resistance

V= input voltage

 

The aim is to drop the input voltage to 1.7 volts with a current of 20mA. The flat side of the LED is negative. Don't get stressed if you get the polarity wrong, just reverse it.

they dont all use 20ma though!? it varies on size and light output

[Mad Professor 7]

Or go out and buy a 12v LED

 

I'll go now

[smckeown 1]

can you buy 12v LEDs ?

[Craigb 2]

can you buy 12v LEDs ?

 

Sean Try vehicle wiring products 0115 9305454 that's where i got my 12V LED's from

 

 

http://www.vehicle-wiring-products.co.uk/

Edited July 31, 2006 by Craigb

[smckeown 1]

cheers craig, i love a simple solution

[Rob_the_Sparky 9]

You need to know the spec of the LED. 12V LEDs simply have the resistor built in, these are the ones I'd use as they are much less hassle to use. Just remember that if you wire them up backward they won't work.

 

Rob

[smckeown 1]

I looked at the company craig mentioned but they looked a tad boring. I've since found this company http://www.ultraleds.co.uk/, and they have some nice and bright L.E.Ds that should do the trick:

 

 

 

 

[phatgti 0]

I did 3 years on electronics at GCSE level and the only thing i remember about LED's are that you wire them "short leg to neg"