2007-1 WorldAcademics World Academics Journal of Engineering Sciences ____________________________________________________________ World Acad. J. Eng. Sci. 01 2007 (2014) ISSN: 2348-635X doi:10.15449/wjes.2014.2007 Performance Comparison of Signal Conditioning Circuits For Light Intensity Measurement D. Nagaraju, C. H. Kireet, N. Pradeep Kumar and Ravi Kumar Jatoth 1 Department of ECE, NIT Warangal- 506 004, India. Email: dnagarajuece@gmail.com, kireet.chede@gmail.com, npradeep465@gmail.com, ravikumar@nitw.ac.in Abstract: Light enables us to view, perceive and enjoy the various forms of visual communication. Inadequate light may lead to problems like lack of interest, failure to concentrate, sleepiness and apparent laziness. Further, eyestrain, headache, indigestion and irritability are the other problems due to inadequate light. In residential homes, the living room being used for different kinds of activities like, relaxation, family entertainment, get together etc., which require variety of lighting techniques. Study room is also an important area where a lot of close visual tasks and skilled work are performed which require suitable type of lighting of adequate quantity. Hence measurement of light intensity is the important task to main required LUX levels for various workplaces. To accurately measure the light intensity in a given spot, it is best to use a light meter. In commercial light meters different signal conditioning circuits are used. Selecting a suitable signal conditioning circuit is an important task for instrumentation engineer. So, this paper tries to evaluate the performances of different signal conditioning circuits in terms of linearity, sensitivity and accuracy. Ke ywor ds: lux, sensitivity, linearity, accuracy. Introduction Light intensity measurement can be done using different sensors. Mostly preferred sensors are LDR and photo diode. In most of the applications measurement of light intensity is necessary to maintain required amount of light. We can consider the following applications as an example. Lighting for Poultry Housing: Light intensity is an important management factor for breeder type poultry. There is evidence suggesting minimum threshold intensity is needed to obtain optimal reproduction performance. Light levels (intensity or illuminance) and the duration of light (photo period) are important factors in poultry production. Light intensity is affected by many variables: lamp type (i.e., incandescent versus fluorescent, versus high pressure sodium, versus metal halide, versus low pressure sodium, etc.); reflectance of the floor, walls, ceiling; height of the lamp fixture above the working plane; dirty conditions, and maintenance schedule Note: (1) Based on rooms with 10' heights to work plane with relatively dirty, dull walls, ceiling and floors. (2) Based on rooms with 7' heights to work plane with relatively right walls, ceiling and floors. (3) Based on small areas with 4' height to work plane with bright reflective shrouds, and relatively bright walls and work surfaces. For specific tasks such as detailed work bench, egg processing. Lighting For Commercial Green House: In commercial greenhouses, several strategies can be used to help properly manage light levels throughout the day and seasonally. Some of the primary reasons why greenhouses manipulate light levels include temperature and irrigation management, photoperiod control, minimizing crop stress, and optimizing photosynthesis i.e. The amount of light received by a plant is an important factor, because plants' growth