Lichtstroms

Lichtstroms, also known as luminous flux, is a measure of the total amount of visible light emitted by a source per unit of time. It is a photometric quantity, meaning it accounts for the sensitivity of the human eye to different wavelengths of light. The unit of luminous flux is the lumen (lm). A lumen is defined as the luminous flux of one ISO standard candle emitted per unit solid angle.

The concept of luminous flux is distinct from radiant flux, which measures the total electromagnetic power emitted by a source, regardless of whether it is visible to the human eye. The conversion between radiant flux (measured in watts) and luminous flux (measured in lumens) depends on the spectral distribution of the emitted radiation and the luminosity function of the human eye. This conversion is not linear, as the human eye is most sensitive to light in the green-yellow portion of the spectrum.

Luminous flux is a fundamental property used to characterize the brightness of light sources. For example, a typical 60-watt incandescent light bulb might produce around 800 lumens, while a similar energy-efficient LED bulb could produce the same or even more lumens while consuming significantly less power. Understanding luminous flux is crucial in applications such as lighting design, where it helps determine the appropriate number and type of light sources needed to illuminate a space effectively. It allows for objective comparisons of the light output of different lighting technologies.