I've connected an MQ6 gas sensor to the output of a 78L05 5 V regulator, with its input connected to the + terminal of a Duracell 9 V battery. The DOUT pin of the MQ6 is connected to the - terminal of a buzzer.

After a while, the green light on the MQ6 indicating that it is operational goes out, the red light indicating that there is a gas leak lights up very dimly and the buzzer starts to sound even though there is no leak.

When I disconnect the whole thing and let the battery rest for a while, the sensor starts working again until it stops working properly.

can anyone tell me what's wrong with my project ? I was inspired by this project https://www.youtube.com/watch?v=wq1bM2EpRdI but I had to add a voltage regulator because the MQ6 requires a voltage of 5 volts.

enter image description here

Datasheet : https://joy-it.net/files/files/Produkte/SEN-MQ6/SEN-MQ6_Datasheet_2023-09-26.pdf

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    \$\begingroup\$ You need to improve the information. A proper schematic is needed, and a link to the datasheet of the gas detector. \$\endgroup\$
    – MrGerber
    Commented Jan 27 at 13:25

1 Answer 1


The MQ6 has a heater inside it that draws about 200 mA @ 5 V. This is far more than a standard rectangular 9V battery can supply for any length of time.

  • \$\begingroup\$ So the heater is the cause of the problem. How do I improve my design ? use a 220V-5V adapter ? \$\endgroup\$
    – Aminos
    Commented Jan 27 at 13:43
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    \$\begingroup\$ And the 78L05 is usually not very happy about being used at ~2x its max output current. \$\endgroup\$
    – MrGerber
    Commented Jan 27 at 13:47
  • \$\begingroup\$ According to the datasheet I was able to find on google - MQ6 does not, on the other hand, have a green or red light on it, as OP claims. So there might be other issues in the circuitry that we don't know about. \$\endgroup\$
    – MrGerber
    Commented Jan 27 at 13:48
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    \$\begingroup\$ @Aminos So the heater is the cause of the problem. ... no, the insufficient power supply is the cause of the problem \$\endgroup\$
    – jsotola
    Commented Jan 27 at 17:17
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    \$\begingroup\$ @Aminos: you have a module containing an MQ6 sensor and other circuitry, not a plain MQ6 sensor - it is important to state that. \$\endgroup\$ Commented Jan 27 at 17:34

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