. The construction and application of a cheap, simple and portable colorimeter
is presented. The system employs an LED as a light source and a common
photocell (photoresistor) as a detector. The device functions based on the level of light
received by photocell, which is connected to a digit multimeter yielding resistance
readings. Resistance increases with increasing the sample absorption. Due to the
simplicity of the instrument it can be constructed in a laboratory or a classroom. The
fabricated device is applicable to calculate the molar absorption of colored species
and demonstrates the basics of the instrumentation of spectrophotometers.