Note: A NDIR instrument for multicomponent gas detection using the galvanometer modulation.

The non-dispersive infrared (NDIR) instruments are widely applied to multicomponent gas detection in many fields. In this paper, a NDIR instrument using the galvanometer modulation is proposed, which has a common optical path for multicomponent gas detection. Compared with the conventional NDIR instrument using the chopper modulation, the proposed instrument with a simpler configuration has better detection efficiency and stability. The proposed instrument has been successfully used to measure the main gas components of vehicle emissions. The NDIR instrument using the galvanometer modulation has great potential for remote sensing application, where multicomponent gas is always spatially inhomogeneous.