Light Dependent Resistance as a Sensor in Spectroscopy Setups Using Pulsed Light and Compared with Electret Microphones

Light-dependent resistances (LDR) are cheap light sensors. A less known light detector is the electret microphone, whose electret membrane functions as a perfect absorber, but only detects pulsed light. The aim of this study was to analyze the use of a LDR and an electret microphone as a light sensor in an optical spectroscopy system using pulsed light. A photoacoustic spectroscopy setup was used, substituting the photoacoustic chamber by the light sensor proposed. The absorption spectra of two different liquids were analyzed. The results obtained allow the recommendation of the LDR as the first choice in the construction of cheap homemade pulsed light spectroscopy systems.