LED basics everyone should know

Aug 1, 2018 1:50:00 PM

Some of These LED basics definitions still new for many members in LED lighting business we trying to collect it in a simple format that is easy to understand and only as they relate to LEDs. You will find these definitions easy to apply towards any LED product described here on our website

Bulb

Is not a LED.  A bulb is a light bulb, an MR17 or E27 base light bulb. A LED light bulb is a finished product that has the LEDs installed; electrical components installed and is ready to be used by the consumer. A LED light bulb is screwed in place, twisted and locked in place, pressed into sockets or contact terminals.

Bulb Base

This part of the bulb is used to set it into place and to make contact with electricity. There are many types and sizes. Most common are E27/E27, USA and European standard household size, or medium base as it often is called. The 26 or 27 equates to the diameter measurement in millimeters of the threads of a screw in base bulb. This type of bulb includes the PAR20, PAR30 and PAR28 types. There are MR16 and MR11 type base LED bulbs as well as GU10’s. There are also E12 candelabra base LED light bulbs

Chromaticity

Chromaticity is an objective specification of the quality of a color regardless of its luminance. Chromaticity consists of two independent parameters, often specified as hue (h) and colorfulness (s), where the latter is alternatively called saturation, chroma, intensity, or excitation purity.

CRI – Color Rendering Index

Also CCT or Correlated Color Temperature. It is a measure of the quality of light. A measurement of the amount of color shift that objects undergo when lighted by a light source as compared with the color of those same objects when seen under a reference light source of comparable color temperature. Higher CRI equates to sharper, crisper, more natural colored pictures while at the same time, reducing glare.

Color Temperature K

A measure of the color of a light source relative to a black body at a particular temperature expressed in degrees Kelvin (K). Incandescent lights have a low color temperature (approx. 2800K) and have a red-yellowish tone. Warm white LED Lamps have a color temperature between 2700-3500K. Lamps rated between 5000K and 6000K are viewed as white, while lamps above 6000K tend to have a blue cast.

LED

A light-emitting diode (LED) is a semiconductor device that emits light when an electric current passes through it. The light is not particularly bright, but in most LEDs it is monochromatic, occurring at a single wavelength. The output from an LED can range from red (at a wavelength of approximately 700 nanometers) to blue-violet (about 400 nanometers). Some LEDs emit infrared (IR) energy (830 nanometers or longer); such a device is known as an infrared-emitting diode (IRED).

LED  Array

LED arrays are assemblies of LED packages or dies that can be built using several methods. Each method hinges on the manner and extent to which the chips themselves are packaged by the LED semiconductor manufacturer. The intensity & uniformity of light output from an array depends upon the method of LED array manufacturing used.

LED Drivers

LED drivers are current control devices that replace the need for resistors. LED drivers respond to the changing input voltage while maintaining a constant amount of current (output power) to the LED as its electrical properties change with temperature.

LED Lighting

A general term used by those who do not know the specific type or category of LED lighting they are after. LED lighting includes LED bulbs and fixtures, strips, clusters, fluorescent tube replacements and so forth.

Ambient temperature (Ta)

The surrounding temperature level in a given area in which a LED light source is expected to operate within for a good lighting product it should be between -20 to +55

IP factor

The ‘IP’ International Protection Marking Code is a standard also commonly interpreted as Ingress Protection Marking – it rates the inherent degree of sealing protection provided by the mechanical casing/electrical enclosure of a device against intrusion from foreign bodies

Lumen Maintenance factor

is the luminous flux remaining (expressed as a percentage of the initial output) at any selected elapsed operating time. Lumen maintenance compares the amount of light produced from a light source or from a luminaire when it is brand new to the amount of light output at a specific time in the future. For instance, if a luminaire produced 10,000 lumens of light when it was brand new and now produces 8000 lumens of light after 30,000 hours, then it would have lumen maintenance of 80% at 50,000 hours. Useful lifetime estimates for LED lighting products are typically given in terms of the expected operating hours until light output has diminished to 80% of initial levels denoted L80 life

Lumens and Lux

The unit of luminous flux in the Internatonal System equal to the amount of light given out through a solid angle by a source of one candela intensity radiating equally in all directions. Used to measure light bulbs as stand alone light sources. Lighting fixtures are measured by lux output which is lumens per square meter. The higher the lux reading the more light the fixture is producing over a given area. Known as lumens per square meter

RGB

RGB stands for red, blue and green, the three primary colors that make white light and all other colors. It can be a pre-programmed 7 color automatically changing LED bar or strip that is non-adjustable. It also means a RGB color changing system which allows adjustment of color change frequency, strobing, chasing and other action modes by using a color controller.

SMD/SMT

A type of low profile LED that is surface mounted to a PCB. These type LEDs are very powerful. These have the most promise in delivering light levels and coloring that we are used to having.

COB (Chip on Board)

COB ‘Chips-On-Board’, It is Multi LED chips (0.2W or 0.5W or 1W) are packaged together as one lighting board. The material of lighting board can be aluminum or copper or Ceramic.

View Angle

Also referred to as directivity or the directional pattern of a LED light beam. The expressed degree indicates the width of the light beam and also controls to some extent, the light intensity of a LED. View angles range from 8 to 360 degrees and are provided through the use of optics which are special lenses made to collimate light into a desired view angle.

Amp, Amperage, Milliamps

Amp is the basic unit of electric current adopted under the System International. A typical household circuit carries 15 to 50 amps. Amperage is the strength of an electrical current measured in amperes. The higher the amperage numbers the higher the ability to place more devices on a circuit that will be driven by that amperage. mA stands for milliamps. 1000mA equals 1 amp.

Watt

consumption by an electrical device when it is in operation. The energy cost of operating an electrical device is calculated as the wattage times the hours of use. In single phase circuits it is related to volts and amps by the formula: V x A x PF (power factor) = W. More and more we are getting away from stating brightness of a product by use of incandescent watts comparisons. Consumers now are used to lumen ratings which are more pertinent today.