DIY Kit MQ-3 Sensor Alcohol Detector Tester Alarm System Electronic KIT

Description: Alcohol concentration alarm circuit This circuit is mainly an alarm control circuit formed by the gas sensor group MQ-3. When the sensor MQ-3 is in the environment where alcohol vapor exists, the conductivity of the sensor will be the same as the alcohol vapor concentration. Increase and increase. By measuring the series partial pressure between the sensor and the fixed resistor, the alcohol content in the environment can be judged. Working voltage: 5-7.5V DC Circuit Description: This circuit can be powered by 5-7.5V DC power supply, switch S1 is the power switch, resistor R1 and LED D1 are used for power indication. The internal sensor MQ3 needs to be heated to a certain temperature during operation, so its internal installation There is a heating wire, the resistor R4 is the current limiting resistor of the heating wire, and the heating of MQ-3 is normal after power-on. When MQ-3 does not detect alcohol vapor, its internal resistance is very large, the voltage drop of