Cytron Technical Forum

I am confused why both the SN-MQ7 and SN-MQ9 sensors' pin2-VCC and pin3-GND are interconnected ? Can someone help me?

do you refer from shematic provided by cytron? if yes, that not connect, but if there red dot, that mean it connect each other.

There is no red dot on the sensor.I use the digital mutlimeter to check the continuity but still found that those 2 pins are interconnected. What is the problem and solution you suggest? Thanks.

If you check the schematic and the datasheet, the VCC and GND is connected to the heating coil, and most of the coil is low resistance. If you use continuity test, you will get buzzer when resistance is low, try use low resistance test instead, example 200 ohm.

Thanks for your explanation. In overall, even both pins are connected to heating coil there will be no problem for the sensor to use?