HOW TO CHOOSE THE RIGHT TYPE OF LIGHT - Comparison Between Incandescent Bulbs, Fluorescent Bulbs &Tubes, LEDs or Light Emitting Diodes, Kelvin, CRI, Lumen, Lux, mcd, Candela, Volts, Amps, Watts, 2000K, 3000K, 4000K, 5000K, 6000K, emergency lights, lamps, battery chargers, ups backup, inverters

How To Choose The Right Type Of Light
This article explains in layman's language the meaning of all the specifications attached to an electrical light source like Kelvin, CRI, Lumen, Lux, mcd, Candela, Volts, Amps, Watts, etc. and also provides comparative values.

Type Of Lights

The three main categories of lights popularly in use today are:
1) Incandescent Bulbs
2) Fluorescent Bulbs &Tubes
3) LEDs or Light Emitting Diodes

Commonly Used Specifications

Following are the meanings of various specifications available on lighting devices.

K or Kelvin

K or Kelvin is the unit used to measure the temperature of light. In layman's terms it is nothing but the different shades of light. The following examples will explain this better.
1900K stands for candle light or the light at sunrise or sunset. (e.g.- LEDs)
2600K to 3500K is called as warm light. (e.g. - LEDs, incandescent bulbs)
4000K to 4500K is called as natural light and used for general lighting. (e.g. - LEDs, fluorescent tubes)
5000K to 5600K is called daylight or the light of sun available at noon time. (e.g.- LEDs)
Above 6000K is called cool light as it starts with a bluish tint which goes on increasing with the increase in K value. (e.g.- LEDs)
*** The K value pleasing to people varies for person to person. More over the choice of men differ from women and so forth. Hence selection has to be made according to individual tastes.

CRI - Color Rendering Index

It is the measure of the ability of a light source to make objects appear closest to the color they would appear under an ideal natural light source. This comparative value is usually indicated as a percentage.Therefore higher the CRI better is the clarity of the color of objects. See images at bottom of page.

Lumen, mcd and Lux

Lumen is the unit used to measure Intensity of light emitted by a source in a single direction.
Candela is the unit used to measure amount of light produced by a source 360 degrees around it.
1 Candela is approximately equivalent to 4 Lumen.
Candela is also referred to as the light produced by 1 Candle.
1000 milli Candela or mcd is equal to 1 Candela.
1 Lumen per sq. meter is called as Lux.

*** Therefore the important things to be noted when selecting a light source is the value of K, CRI and mcd or Lumen. The brightness is directly proportional to the value of lumen.

Volts, Amps and Watts

The unit for measuring voltage is volts (V).
The number associated with V indicates the supply voltage required to operate the light.

The unit for measuring current is Amps (A) or Milli Amps (mA). Note: 1A=1000mA
The number associated with A or mA indicates the amount of current drawn from the supply.

The unit for measuring power or energy is watts (W).
The number associated with W indicates the amount of power or energy that will be consumed by the light.

These three values do not in any way indicate the amount of light or brightness. Normally only two of the above values are provided because the third can be calculated using the equation. Power (in Watts) =Voltage (in Volts) x Current (in Amps)

Example:

Let us try to understand the meaning of the following specifications on a light source.
110v-230v, 10000mcd, 2000K, 1W
110v-230v - This light source requires supply voltage in the range of 110 volts to 230 volts to operate.
10000mcd - The amount of light produced by this source is 40 Lumen. (10000mcd = 10 Candela = 4x10 Lumen)
2000K - The color of this light will be close to the color of candle light.
1W - This light source will consume power of 1W. i.e. - if this light is run for 1000 hours it will consume 1Kwh or 1unit of power.