Authors : Janchai YINGPRAYOON*, Worapat PARIVATTHANAKIT and Thanawat KONGSUK
Page Nos : 1-3
Description :
This project is to study the way to construct a simple densitometer by using a phototransistor as a detector of light intensity. According to Beer-Lambert Law, we can measure the light intensity passing through a radiographic film to obtain an optical density. To measure the optical density of the film over a very wide range, a logarithmic operational amplifier is needed to measure a current flowing through a phototransistor which will give a calibration curve to obtain an optical density indirectly. This can be a main principle for construction of a densitometer.
