Abstract:
An NDIR gas detector includes a photodetector for detecting a portion of stray visible light emitted from an incandescent lamp so as to generate an induced electrical signal, which is compared with a preset reference signal associated with a predetermined constant level of the stray visible light corresponding to a constant temperature of the lamp so as to obtain a level difference between the induced electrical signal and the reference signal. Electrical power supplied to the lamp is repeatedly regulated based on the level difference until the induced electrical signal and the reference signal have the same level, thereby stabilizing IR emission of the lamp in response to the lamp being kept at the constant temperature.