Is my MQ-2 gas sensor analog or digital? I have this MQ-2 gas sensor for an Arduino Uno:







I found these two articles about how to use it:


https://create.arduino.cc/projecthub/Aritro/smoke-detection-using-mq-2-gas-sensor-79c54a
http://www.instructables.com/id/Ardunio-Smoke-And-Gas-SensorMQ-2/?ALLSTEPS


But I need to know if the sensor is analog or digital.
Also I would like to know what is the blue switch for.

This questions help me a bit:

It says that he use an analog sensor. But as this sensor is not mine I don't want to brake it or burn it.
Your sensor is analog. I have the same one. By the way, there is no chip on board, so it cannot form a digital signal ;)