The SI unit of luminous intensity. One candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 × 10¹² Hz and has a radiant intensity in that direction of 1/683 watt per steradian.
- ‘SI (Système Internationale d' Unites) uses seven different fundamental units, the meter, kilogram, second, ampere, kelvin, candela, and mole.’
- ‘These types of detectors should be calibrated in lumens/amps, which allows easy calculation of candela values.’
- ‘According to the spec sheet, the FP231W is supposed to deliver about 250 candelas / square-meter of brightness.’
- ‘We have a 15-inch demo and a 50-inch demo, and have achieved 600 candelas per square meter generating 1 millimetre sized pixels.’
- ‘Nits are also a measure of luminance, in so many candela per square metre.’
1950s: from Latin, candle.