Illuminance Unit Converter

What is Illuminance?

Illuminance is a measure of how much luminous flux is spread over a given area. It is the total luminous flux incident on a surface, per unit area. Illuminance is a key concept in lighting design, photography, and other fields where the intensity of light falling on a surface is important.

Formula and Units

The basic formula for illuminance is:

\[E = \frac{\Phi}{A}\]

Where:

• \(E\) is the illuminance
• \(\Phi\) is the luminous flux
• \(A\) is the area

Common illuminance units include:

• Lux (lx): The SI unit of illuminance, equal to one lumen per square meter
• Foot-candle (fc): Equal to one lumen per square foot (approximately 10.764 lux)
• Phot (ph): Equal to 10,000 lux
• Nox (nx): Equal to 0.001 lux

Calculation Steps

To convert between illuminance units, follow these steps:

1. Identify the initial and target units
2. Use the conversion formula: \(E_{target} = E_{initial} \times \frac{ConversionFactor_{initial}}{ConversionFactor_{target}}\)
3. Apply the appropriate conversion factors
4. Calculate and round the result to the desired precision

Example and Visual Representation

Let's convert 1000 lux to foot-candles:

\[1000 \text{ lux} \times \frac{1 \text{ foot-candle}}{10.764 \text{ lux}} \approx 92.9 \text{ foot-candles}\]

This diagram illustrates the concept of illuminance. The central circle represents a light source, and the radiating lines show the light spreading over an area. The conversion demonstrates that the intensity of illumination remains constant, whether measured in lux or foot-candles.