In this note, we are going to learn about Lux Meter and about its Construction, Working Principle, and Applications as well. Welcome to Poly Notes Hub, a leading destination for engineering notes for diploma and degree engineering students.
Author Name: Arun Paul.
What is Lux Meter?
A luxmeter is a device that measures the illuminance, or quantity of light falling on a surface, which is commonly measured in lux (lx). It is widely utilized in many disciplines, including photography, filmmaking, workplace lighting assessments, and architectural lighting design, to ensure that light levels are adequate for the activity or environment.
Lux Meter Diagram
Typically, a luxmeter is made up of the following key parts –
- Photodetector or Sensor: The photodetector, which transforms light into an electrical signal and is typically a photodiode or a photoresistor, is the brains behind the luxmeter. Because of its sensitivity to light intensity, the photodetector generates a voltage or current in direct proportion to the amount of light it receives.
- Optical Filter: An optical filter, often a color-corrected filter, is placed in front of the photodetector. This filter mimics the spectral sensitivity of the human eye, ensuring that the luxmeter measures light in a way that closely matches human perception.
- Amplifier: The photodetector produces a very small electrical signal that must be amplified. An electronic amplifier is used to increase this signal to a level that allows it to be reliably measured and shown.
- Analog to Digital Converter: The amplified signal is then transferred via an analog-to-digital converter, which turns it into a digital format that the device can process and display.
- Display Unit: The processed signal is shown on a digital readout, usually in lux. Some modern luxmeters provide capabilities such as data logging, storage, and transfer options.
- Power Supply System: Luxmeters are powered by batteries or an external power supply. The power supply is in charge of providing the energy required to operate the luxmeter’s electronic components.
Lux Meter Working Principle
The luxmeter detects light using a photodetector, which produces a tiny electrical output proportionate to the light intensity. This light is first filtered using an optical filter that simulates the spectral response of the human eye, ensuring that the measurement accurately reflects human perception. The weak electrical output from the photodetector is then amplified to a detectable level. An analog-to-digital converter (ADC) converts the amplified signal from analog to digital format, allowing the data to be processed by the luxmeter’s microcontroller.
Finally, the light intensity is presented in lux on the device’s screen, allowing for immediate reading. Calibration against a known standard light source guarantees that measurements are accurate.
Lux Meter Uses
Here we have listed some applications of Luxmeter in Lighting System –
- Used in workplace lighting arrangement.
- Used in photographic and cinematic lighting.
- Used in architectural lighting design.
- Used in horticulture as well.