March 2014

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AN4451

Application note

Signal conditioning for a UV sensor

Nicolas Aupetit

Introduction

This application note describes the analog conditioning circuit used for a high impedance sensor that

acts like a current sensor. It explains how to condition a signal coming from the sensor - in this case an

ultraviolet (UV) sensor - and how to improve performance.

While sunlight is important for our health, overexposure to it carries significant health risks. For example,

sunburn is caused by the UV radiation contained in sunlight. Measurement of UV is important from a

medical point of view, but for various other reasons too. The detection of UV rays is important in the

industrial domain, particularly to detect flame in a blue flame oil burner or in some fire detectors.

Knowing the right levels of UV for plant growth is also important. Low levels of UV light have a positive

effect on plant growth and seed germination but, higher levels can be harmful and even toxic. UV is part

of our life and if it is not well controlled it can cause damage. Consequently, UV sensors are very

important.