Digital Colorimeters The basic set-up of the Digital Colorimeters is: A. LED light source: Produces polychromatic light over the entire visible region,B. Broad spectrum filter: The colorwheel has eight different filters. The filter employed is selected by wavelength. Each filter will produce monochromatic light at a specified peak wavelength with a bandpass of 20 nm. The filters enable the user to perform tests from 400 to 680 nm.,C. Cuvette Holder: It holds the inserted cuvette during testing. It is imperative the cuvette be consistently oriented in the holder. Round cells usually have orientation markings to correctly position the cuvette.,D. Detector: A silicon photo diode is used as the detector. The photo detector current will change as a function of light energy.,E.Display:Thecurrentsignalfromthedetectorisconvertedtoanumericalvalue, absorbance and is shown on led display.