Nondispersive Infrared Sensor

Nondispersive infrared sensors, commonly abbreviated NDIR, detect specific gas concentrations by measuring infrared light absorption at a fixed wavelength corresponding to the target gas molecule. Unlike dispersive spectroscopy methods that separate light into a full spectrum, NDIR sensors use a single fixed-wavelength optical filter, making the design simpler, more compact, and significantly less expensive to manufacture while maintaining strong accuracy for the targeted gas type.

The core sensor architecture houses an infrared light source, typically a broadband incandescent or LED emitter, positioned across a gas sample chamber from a photodetector fitted with a narrowband optical filter matched to the target gas absorption wavelength. Carbon dioxide detection commonly uses a 4.26 micron filter, while methane and other hydrocarbon gases use filters around 3.3 microns. Additionally, a reference channel without gas absorption interference compensates for light source drift and contamination buildup, maintaining measurement accuracy over the sensor’s operational lifespan.

Measurement range varies by target gas, with CO2 sensors commonly covering 0 to 5000 ppm or higher for industrial applications, while combustible gas detection units measure in percentage of lower explosive limit. Furthermore, response time typically runs between 10 and 30 seconds for 90% of full reading, with sensor lifespan extending 5 to 10 years due to the absence of consumable chemical reagents found in electrochemical alternatives.

Output signal options include analog 4-20mA current loop, voltage output, and digital protocols such as I2C, UART, or Modbus depending on the integration platform. Moreover, operating temperature range typically spans -20°C to +50°C, with humidity tolerance up to 95% non-condensing, supporting deployment across Pakistan’s varied climate zones from coastal humidity to dry northern conditions.

Tactical Supply Pakistan supplies nondispersive infrared sensors to industrial gas monitoring installations, HVAC system integrators, security screening checkpoints, and environmental monitoring stations requiring long-term, low-maintenance gas detection across Pakistan.