MQ303A Alcohol Sensor
Character
* High sensitivity
* Fast response and resume
* Long life and low cost
* Mini Size
Application
MQ303A is semiconductor sensor is for Alcohol detection,
It has good sensitivity and fast response to alcohol,
suitable for portable alcohol detector.
Configuration
Technical Data
Model No. MQ303A
Sensor Type Semiconductor
Standard Encapsulation Metal
Detection Gas Alcohol
Concentration 20-1000ppm Alcohol
Heater Voltage V 0.9V 0.1V AC or DC
H
Loop Voltage V 6V DC
c
Load R
L
Standard Adjustable
Resistance
Circuit
Heater
Conditions
R 4.5 0.5 Room Tem.
H
Resistance
Heater Current I 12020mA
H
Heater Power P 140 mW
H
Sensor
P 10 mW
S
Consumption
Sensing
R 4K-400K(in air)
s
Character Resistance
Rs(in air)/Rs(125ppm
Sensitivity S
Alcohol) 3
Slope 0.50 0.15(R300ppm/R100ppm Alcohol)
Tem. Humidity 20265%5%RH
Vc:3.0 V0.1 V DC
Condition Standard test circuit
VH: 0.9 V0.1 V DC
Preheat time Over 48 hours
Sensing element of the semiconductor sensor is a
micro-ball, heater and metal electrode are inside,
and the sensing element is installed in
anti-explosion double 100 mesh metal case (see
the above)
Sensitivity Characteristics Influence of Temperature/Humidity
Fig.2 is the test circuit. You could get resistance Fig 3 is sensitivy of MQ303A, it reflects
change from voltage change on fixed or adjustable relations between resistance and gas
load resistance. Normally, it will take several concentration, resistance of the sensor
minutes preheating for sensor enter into stable reduce when gas concentration increases
working after electrified; oryou could give
2.20.2V high voltage for 5-10secs before test,
which make sensor easily stable.
Notification
1 Following conditions must be prohibited
1.1 Exposed to organic silicon steam
Organic silicon steam cause sensors invalid, sensors must be avoid exposing to silicon bond,
fixature, silicon latex, putty or plastic contain silicon environment
1.2 High Corrosive gas
If the sensors exposed to high concentration corrosive gas (such as H Sz, SO Cl HCl etc), it will
2 X 2
not only result in corrosion of sensors structure, also it cause sincere sensitivity attenuation.
1.3 Alkali, Alkali metals salt, halogen pollution
The sensors performance will be changed badly if sensors be sprayed polluted by alkali metals salt
especially brine, or be exposed to halogen such as fluorin.
1.4 Touch water
Sensitivity of the sensors will be reduced when spattered or dipped in water.
1.5 Freezing
Do avoid icing on sensorsurface, otherwise sensor would lose sensitivity.
1.6 Applied voltage higher
Applied voltage on sensor should not be higher than stipulated value, otherwise it cause down-line or
heater damaged, and bring on sensors sensitivity characteristic changed badly.
1.7 Voltage on wrong pins
For 6 pins sensor, if apply voltage on 13 pins or 46 pins, it
will make lead broken, and without signal when apply on 24 pins
2 Following conditions must be avoided
2.1 Water Condensation