Most thermopiles are hermetically sealed with an inert gas in the package at one atmosphere pressure. The selection of encapsulating gas allows customization of detector output sensitivity and time constant without affecting other parameters such as resistance or noise.
Application Briefs
Variations in Calibrations of Radiometers Using Cut-on Optical Filters
The amount of optical energy falling on the thermopile will depend on the transmission characteristic of the filters used as the window in the detector. This brief discusses the effect of the variation in the bandwidth of the filter in the calibration of a radiometer.
Temperature Compensation of a DC Radiometer
Since a thermopile is an array of thermocouples, the temperature of the cold junction of the thermocouple must be known to provide an accurate temperature measurement. This brief describes a method for dealing with a variation in the cold junction temperature.
A Simple DC Radiometer
This brief explains the basic principles of remote temperature measurement using thermopiles.
Emissivity Correction for a Radiometer
The optical power emitted by a target will depend on its emissivity and temperature. A simple technique to take into account the change in sensitivity is described.
Infrared Radiation and Radiometry Introduction
In this brief we discuss how an object’s temperature affects the peak emitted spectral wavelength according to Wien’s Displacement Law. Several spectral curves are included to illustrate.
Introduction to Thermopile Detectors
The basic principles and nomenclature of thermopile detectors are explained. There is also an explanation of the types of thermopile detectors available from Dexter Research, as well as an abbreviated list of the ever-growing applications for thermopile detectors.