Patent ID: 7245373
Filing Date: 2007-07-17
Classification: G01J,G01N

Abstract:
1. A spectrometer system comprising: a thermal light source for illuminating a sample, wherein the thermal light source comprises a filament that emits light when heated; a spectrograph for measuring a light spectrum from the sample; an electrical circuit for supplying electrical current to the filament to heat the filament and for controlling a resistance of the filament, the electrical circuit comprising: a power supply that supplies current to the filament; first electrical components that sense a current through the filament; second electrical components that sense a voltage drop across the filament; third electrical components that compare a ratio of the sensed voltage drop and the sensed current with a predetermined value; and fourth electrical components that control the current through the filament or the voltage drop across the filament to cause the ratio to equal substantially the predetermined value.