Digital Turbidity/Nephelo Meter are ideal instruments for the measurement of suspensions. They consist of a light source focused on a test tube containing the sample solution under test. The light, reflected at a right angle to the focused light by the suspension in the solution, is detected by the photodiode detector, amplified and displayed on 3 1/2 digit seven segment LED display. It operates on 230 V and has a frequency of 50 Hz.