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LED Lighting Contd.

LED Terminology

Beam angle
The beam angle refers to how focused the light is when emitted from the LED. This angle is determined by measuring the angle from direct on-axis to the angle where light intensity falls to half of the on-axis intensity, and multiplying this difference by 2. The choice of viewing angle also affects the LED output intensity.

Ledzworld LEDs are sorted into different bins (groups) based on their wavelength, photometric luminous flux, or radiometric power data. Bin ranks describe the specifications of the given bins.

The candela is the SI base unit of luminous intensity; that is, power emitted by a light source in a particular direction, weighted by the luminosity function (a standardized model of the sensitivity of the human eye to different wavelengths, also known as the luminous efficiency function. An ordinary wax candle generates one candela.

Correlated Color Temperature, CCT rating is an indication of how "warm" or "cool" the light source appears.

In easy terms CRI is the quality of light and is represented by a number from 1 (worse) to 100 (best).  A CRI of 100 means the light has the same quality as sunlight, it is pleasant and all colors look natural.  At CRI of 60 the light has an unpleasant feel and colors look unnatural (for example Skin appears less pink, and hence "unhealthy")

The flow of electrons or holes. Measured (in amps) as the number of particles passing a given point per unit of time. Current can be induced by application of an electric field through a conductor or by changing the electric field across a capacitor.

A device used to lower the light output of a source, usually by reducing the wattage it is being operated at. Dimming controls are increasing in popularity as energy conserving devices.

A LED driver is a self-contained power supply that has outputs matched to the electrical characteristics of a LED or array of LEDs.

Efficacy is a figure of merit for light sources. It is the ratio of lumens to power (usually measured in watts). In simple words efficacy is the efficiency of the lamp to convert electricity into light. The way to interpret this is, more efficient LED-lamps provide more light and use less energy.

The process of becoming cooler; a falling temperature. Ledzworld products do not only use the heat-sink to dissipate the heat from the driver but also potting compound. The potting-material is put inside the connector that accommodates the driver. After it dries, it becomes hard, and forms a solid substance with excellent heat-dissipating properties.

A heat sink is a term for a component or assembly that transfers heat, generated within a solid material, to a fluid medium, such as air or a liquid.

The line or plane where the level of P Doping and N doping are equal

Junction temperature
The drive current of an LED is to some extend also converted into heat. The junction temperature TJ [°C], is therefore the sum of the ambient temperature TA [°C], and the temperature rise caused by the power dissipated in the LED as a result of the drive current.

Kelvin temperature
Term and symbol (K) used to indicate the comparative color appearance of a light source when compared to a theoretical blackbody. Ledzworld led lamps are typically 2700K, this makes them truly warm-white.

LED stands for Light Emitting Diode, it is an electronic semiconductor component. If current flows through the diode, it emits light with a wavelength that depends on the semiconductor material.

A lens is an optical device with perfect or approximate axial symmetry which transmits and refracts light, converging or diverging the beam. A simple lens consists of a single optical element. A compound lens is an array of simple lenses (elements) with a common axis; the use of multiple elements allows more optical aberrations to be corrected than is possible with a single element.
Lenses are typically made of glass or transparent plastic.

The lifetime of a LED is the time it can last whilst maintaining a certain percentage of lumen output.
Lumen maintenance
The remaining flux percentage at the rated life of a LED lamp.

Lumen output
A lumen is a unit of standard measurement used to describe how much light is contained in a certain area. The lumen is part of a group of standard measurements known as the photometry group, which measure different aspects of light. For example, a 60 Watt incandescent lamp provides about 800 lumens. Ledzworld’s 10W Superior Bulb provides 500 lumen.

Lux is lumen per square meter. The difference between the lux and the lumen is that the lux takes into account the area over which the luminous flux is spread. 1000 lumens, concentrated into an area of one square meter, lights up that square meter with an illuminance of 1000 lux. The same 1000 lumens, spread out over ten square meters, produces a dimmer illuminance of only 100 lux.

Power factor
A measure of the effectiveness with which an electrical device converts volt-amperes to watts; devices with power factors >0.90 are "high power factor" devices.

Thermal management
Controlling the operating temperature of the product through design, examples includes heat sinks and improved airflow.

A transformer is a device that transfers electrical energy from one circuit to another through inductively coupled conductors-the transformer’s coils.

Trimming implies that every individual LED chip will be connected to its driver. Output and colour temperature are set individually for each lamp. The exact output of the individual LED chip is being electronically adjusted by altering the power-supply to each LED chip, so that the output becomes identical and uniform, despite the different characteristics of the LED.

The voltage between two points is a short name for the electrical force that would drive an electric current between those points. Specifically, voltage is equal to energy per unit charge.

The watt (abbreviated W) is the International System of Units’ (SI) standard unit of power (energy per unit time), the equivalent of one joule per second. The watt is used to specify the rate at which electrical energy is dissipated, or the rate at which electromagnetic energy is radiated, absorbed, or dissipated