General Purpose Low-Cost Flammable Catalytic Gas Sensor

General Description:

The NAP-55A Gas Sensor is a low–cost Catalytic Flammable Gas Sensor designed for the detection and measurement of any Flammable Gas in the range 0-50% LEL. Developed primarily for use in Residential Natural gas and LPG Gas Detectors, the NAP-55A has also been found to be useful in a wide variety of applications where reliable detection of flammable gas leaks and other gas hazards is required at low cost.

The NAP-55A uses the superior catalytic “pellistor” detection principle often used in high quality Industrial Gas Detectors. It hence has many benefits over other low cost gas sensor types.



Detectable Gas:

Detection range:

Voltage supply:

Current drawn:

Signal Sensitivity:

Zero Offset (20oC):

Response time (90%):


Expected lifetime:

Long Term Span Drift:

Long Term Zero Drift:

All Flammable Gases

0 – 50% LEL

2.5V +/- 0.2V

170mA +/- 10 mA

37-53mV / % CH4

0mV +/-  35mV

< 10seconds

+/- 1% LEL

< 3 years

<+/- 2% FSD/ month

<+/- 2mV / year

Operating Conditions:

Operating temperature:

Humidity range:


Temperature Drift (zero):


-10 +50 oC

0 – 95% RH

0.9 – 1.1 atm

<+/- 2% LEL

Effectively linear to 0-100% LEL


  •        Measures flammability directly
  •        Highly resistant to Catalyst poisons
  •        Resistant to shocks and vibration
  •        Effectively Linear output to 50%LEL
  •        Specific to flammable  gases
  •        Unaffected by Humidity
  •        Very Simple circuitry
  •        Very Low Long term drift