Flusso luminoso
Informazioni Luminous Flux Conversione
Luminous flux measures il total amount di visible light emitted da un source in all directions—essentially il "total light output" di un lamp o LED. It's what you see on light bulb packaging un compare brightness. Unlike intensity (candela) which measures light in one direction, o illuminance (lux) which measures light received on un surface, luminous flux captures il complete light production regardless di dove it goes. This makes lumens il fairest way un compare light sources: un 1000-lumen LED e 1000-lumen incandescent produce il same total visible light, though their efficiency (lumens per watt) differs dramatically.
Il SI unit e il lumen (lm). Lumens replaced watt as il standard brightness misurare quando energy-efficient lighting made watt misleading—un 10W LED puo match un 60W incandescent's 800 lumens. Il lumen e defined in terms di candela: 1 lm = 1 cd·sr (candela-steradian). Luminous flux e weighted da human eye sensitivity, peaking at 555 nm (green-yellow)—this e perche lumens misurare perceived brightness, not raw optical power.
Our converter handles luminous flux units e helps understand il relationships tra different photometric quantities.
Luminous Flux Conversions e Relationships
| Da | A | Moltiplica Per |
|---|---|---|
| lumen (lm) | cd·sr | 1 (equivalent) |
| kilolumen (klm) | lm | 1,000 |
| lm | klm | 0.001 |
| megalumen (Mlm) | lm | 10⁶ |
| lm | millilumen (mlm) | 1,000 |
| cd (isotropic source) | lm | 4π ≈ 12.57 |
| lm | cd (isotropic) | 1/(4π) ≈ 0.0796 |
| lm | watt (at 555nm) | 1/683 ≈ 0.00146 |
Key relationships: 1 lumen = 1 candela·steradian. For un point source emitting uniformly in all directions: total lumens = 4π × candela ≈ 12.57 × candela. At 555nm (peak eye sensitivity): 1 watt = 683 lumens esattamente.
Luminous Flux Unita Riferimento
Lumen (lm) – Il SI unit di luminous flux, representing total perceived visible light power emitted da un source. By definition, 1 lm = 1/683 watt at 555nm (peak human eye sensitivity). This definition ties lumens un il photopic luminous efficacy function V(λ). Typical light source outputs: candle ~13 lm, 40W-equivalent LED ~450 lm, 100W-equivalent LED ~1600 lm, car headlight ~1000-3000 lm per bulb, stadium floodlight ~100,000 lm.
Candela steradian (cd·sr) – Mathematically equivalent un il lumen da definition. This notation explicitly shows il relationship tra luminous intensity (candela) e il solid angle (steradian) it illuminates. A 1-candela source emits 1 lumen into each steradian di solid angle; since un complete sphere e 4π steradians, un isotropic 1-cd source emits 4π ≈ 12.57 lumens total.
Kilolumen (klm) – 1,000 lumens. Convenient per high-output sources: professional projectors (3-10 klm), stage lighting (10-50 klm), stadium lights (50-200 klm). Increasingly used as LED technology enables higher outputs da compact fixtures.
Megalumen (Mlm) – 1,000,000 lumens. Used per large-scale lighting installations: sports arena total lighting (50-200 Mlm), major concert stages (10-100 Mlm). Rarely applied un single sources.
Luminous efficacy (lm/W) – While not un flux unit, this ratio e essential per comparing light sources: incandescent 10-17 lm/W, halogen 15-25 lm/W, CFL 50-70 lm/W, LED 80-200 lm/W, theoretical maximum 683 lm/W (at 555nm only). Higher efficacy means more light per watt di electricity.