Bolometer to measure thermal radiation - with resistance variation due to heating effect of bridge current used for bridge tuning

摘要

The bolometer is for measurement of thermal radiation and is part of a measuring bridge. The thermal radiation reaches it in the form of alternating light. A regulator (23) for the bridge (1) supply current controls the current automatically until the resistance ratio in the two arms of the bridge coincide with each other. Pref. three resistances (R2, R3, R4) in the bridges are fixed resistances not dependent on temperature and are about the same size as the bolometer resistance. Pref. the alternating light original is fed to the bridge after amplification in a multiplier in which it is multiplied by a signal inversely proportional to the supply current.