An electrically modulated infrared source typically used in non-dispersive infrared gas sensor is designed by micromachining technologies to replace the traditional infrared sources where modulating components is required

which made the infrared detecting system both expensive and unwieldy.The source is applied in the portable intrared gas sensor to detect different volume fraction of CO

2

and SO

2

gases

and precision is 20×10

-6

and 50×10

-6

respectively

also repeatability less than 10 %.The source could be applied to multi-gas detection development.