15 January 2014 User ReviewCheck your delivery options:
MQ-3 is a semiconductor sensor for Alcohol detection. It has very good sensitivity and fast response to alcohol, suitable for portable alcohol detector. Sensitive material of MQ-3 gas sensor is SnO2, which with lower conductivity in clean air. When the target alcohol gas exist, the sensors conductivity is higher along with the gas concentration rising.As the target gas is present, the conductivity of the gas increases with the concentration of the gas.This sensor detects concentration of alcohol in your breath; An analog output is produced based on the gas concentration. The circuit has a heater. Power is given to heater by VCC and GND from power supply. The circuit has a variable resistor. The resistance across the pin depends on the alcohol content in air in the sensor. The resistance will be lowered if the content is more. And voltage is increased between the sensor and load resistor.
9.3 mm height without the pins