LED Information
GENERAL LED HANDLING PRECAUTIONS
CAUTION: LEDS are static sensitive devices. Observe static sensitivity handling precautions, such as wearing a grounded wrist strap when handling
When forming leads, the leads should be bent at a point at least 3 mm from the base of the led
Avoid damage to LEDS by soldering for no longer than 3 seconds with 700° iron
Please note that the following information applies only to single LED components, not LED Bulbs and Products
All of our LED bulbs and products have resistors built-in for operation at their rated voltages
Please note that LED components are not considered bulbs, an LED bulb is a complete system consisting of LEDs, LED drivers or resistors, and a housing.
DO NOT use LEDS without
a current limiting resistor in series with the LED. The forward voltage rating
is TYPICAL and can vary from part to part, so while some LEDS may work fine
just connected to a battery of the proper voltage, others will be overdriven
and be destroyed.
ALWAYS USE A RESISTOR IN SERIES WITH THE LED OR LEDS
Here are a couple of useful links regarding this issue:
Why do I need a resistor with an LED?
LED Series/Parallel Wizard (for dealing with more than one LED per circuit)
LED calculator: current limiting resistor value
* This calculator rounds the resistance up to the next standard resistor value. You should actually be able to buy a 5% resistor with the value returned by the calculator.
** Power calculations assume use of the standard value current-limiting resistor shown above.
LED calculator version 1.4 Copyright 2001-2004, Rob 'linear' Arnold. All rights reserved.
LED INTENSITY
The unit of measure
commonly used to describe LED intensity is the millicandela (mcd), 1000 millicandela
equals 1 candela. Candelas measures how much light is produced as measured at the light source.
The candela is the Luminous Intensity, in a given direction, of a source of monochromatic radiation of frequency
540 × 1012 hertz and that has a radiant intensity in that direction of 1/683 watt per steradian.
The unit of measure commonly used for most other light sources is the Lumen.
Lumens are units of Luminous Flux and they measure how much light actually falls on a surface.
The Luminous Flux (lumens) from a light source is equal to the Luminous Intensity (candelas) multiplied by the solid angle over which the light is emitted, taking into account the varying intensities in different directions.
So you can see that it is not a simple matter to accurately convert millicandelas (mcd) to lumens but here is link to a handy program that will do it for you:
Luminous Intensity to Lumen Converter
To use leds for 12 Volt applications you must simply connect a resistor in
series with the led or leds. The resistor will drop the excess voltage and limit
the current. See the Forward Voltage spec on the spec sheets (click the LED
pert numbers on the main LED page) for typical and maximum forward voltage,
they're not all the same. Use a 1/8th watt or larger resistor soldered to
the anode of the led and connect the +12 to the resistor. The chart below
shows you the forward current for each color led with a single led in series
with a 470 ohm resistor connected to 12 VDC. The current (and led brightness)
will be slightly higher when the vehicle's engine is running because the battery
charging system keeps the voltage up at around 13~14 volts. You can connect
up to 4 red, orange, or yellow leds in series with each other and one resistor
to power with 12 volts. The value of the current resistor must be lowered,
depending on how many leds are in series. A maximum of 3 of the other colors
can be in series across 12 volts, because of their higher forward voltage
requirement.
See our LED car bulb pages for LED bulbs designed to work on 12 Volt systems
|
LED COLOR |
RESISTOR - Ohms |
CURRENT @ 12 VDC |
|
WHITE |
470 |
18ma |
|
BLUE |
470 |
18ma |
|
GREEN |
470 |
18ma |
|
AQUA |
470 |
18ma |
|
RED |
470 |
20ma |
|
YELLOW |
470 |
20ma |
|
ORANGE |
470 |
21ma |
Custom LED Products and Circuit Boards
We do not do any custom work here at Super Bright LEDs but here's a place that does:
http://www.e-teknet.com or email for your free quote sales@e-teknet.com and tell us superbrightleds.com sent you
TRY
THESE LINKS FOR TONS OF USEFUL LED INFORMATION
The Current State of Solid State Lighting - SSL
