Sun photometry using photodiode open circuit voltage measurements

Abstract

A simple technique is explored in which the open circuit voltage of a photodiode is measured using a simple digital multimeter to monitor the solar irradiance and atmospheric optical depths in three spectral bands. The advantage of this technique is that the photometer only consists of an optical interference filter, photodiode, and a measuring digital multimeter, while the electronics circuitry otherwise needed in a conventional photometer is avoided. This makes the system very simple, cost effective, and versatile for even nonprofessionals to handle.