This part is a kind of semiconductor called MQ-3.

Function of this product has GAS SENSOR.

Manufacturers : HANWEI ELETRONICS

Image and pinout :

Some of the text within the PDF file :

HANWEI ELETRONICS CO.,LTD MQ-3 http://www.hwsensor.com TECHNICAL DATA MQ-3 GAS SENSOR FEATURES * High sensitivity to alcohol and small sensitivity to Benzine . * Fast response and High sensitivity * Stable and long life * Simple drive circuit APPLICATION They are suitable for alcohol checker, Breathalyser. SPECIFICATIONS A. Standard work condition Symbol Parameter name Vc Circuit voltage VH Heating voltage RL Load resistance RH Heater resistance PH Heating consumption B. Environment condition Technical condition 5V±0.1 5V±0.1 200KΩ 33Ω±5% less than 750mw Symbol Tao Parameter name Using Tem Technical condition -10℃-50℃ Tas Storage Tem -20℃-70℃ RH Related humidity less than 95%Rh O2 Oxygen concentration 21%(standard condition)Oxygen concentration [ ... ]

MQ-3 PDF Datasheet Download