How do Lux Meters work?
A lux meter converts incident light into a photocurrent with a silicon photodiode covered by a filter that approximates the CIE photopic response, which matches the sensitivity of the human eye. The signal is amplified and scaled to give illuminance in lux, equal to lumens per square meter. A diffuser and cosine corrector ensure the reading follows the cosine law of incidence and is independent of the angle of arriving light. Because the eye response peaks in the green region near 555 nm, the filter strongly attenuates ultraviolet and infrared radiation. Calibration against a reference lamp or standard photometer sets the absolute scale, and the meter is classified by accuracy and stability according to photometric standards. Temperature and stray light affect reading stability.
Which Lux Meters variants are available?
- Handheld Lux Meter — A handheld lux meter is a compact, battery-powered photometer for quick illuminance checks.
- Benchtop Lux Meter — A benchtop lux meter is a mains-powered photometer for stable laboratory and production measurements.
- Data Logging Lux Meter — A data logging lux meter records illuminance over time at set intervals.
- Spectral Illuminance Meter — A spectral illuminance meter measures the full visible spectrum of incident light and computes illuminance, colour temperature and colour rendering.
- Illuminance and Colour Temperature Meter — An illuminance and colour temperature meter measures both light level and the correlated colour temperature of a source.
How do I choose the right variant?
Choose a handheld lux meter for quick spot checks, surveys and field verification of lighting. Select a benchtop or logging model when measurements must be recorded, averaged or monitored over time. Match the measurement range to the space, since outdoor daylight can exceed 100,000 lux while corridors may be far below 100 lux. Confirm the cosine and colour correction, the stated accuracy class and the sensor calibration. For lighting design and colour work, a spectral illuminance meter adds colour temperature and colour rendering data. Check connectors or remote probes for hard-to-reach locations.
Where are Lux Meters used?
Lux Meters are specified in workplace and occupational lighting surveys, display and monitor brightness verification, greenhouse and plant growth lighting control and public building and road lighting compliance.
Which standards and certifications apply?
Work with Lux Meters is commonly governed by ISO/CIE 19476, DIN 5032-7, CIE S 025, CIE 13.3 and IEC 61010-1. Instrument certifications such as CE marking are confirmed per configuration and never assumed.
What are the key considerations before purchase?
Keep the photopic filter and diffuser clean and free of scratches, because contamination changes the response and biases readings. Zero the instrument in darkness where required, and verify periodically against a calibrated reference lamp or a meter of known accuracy. Avoid shading the sensor and measure at the working plane, holding the sensor in the same orientation as the surface of interest. Note ambient temperature and allow thermal equilibrium. Store meters with the sensor capped, and follow the calibration interval defined by the quality system, often annually.
