Is RL correct for the 3.3V examples?

[bvernham]

Describe the bug A clear and concise description of what the bug is. Not so much a bug but a question In this of the ESP8266 example are you considering RL = 5K? Because the example code is still defaulting to 10K? If the MQ sensor already had a 10K as RL then by adding the voltage divider to "AO" (which is in parallel to "RL" of 10K) aren't you making RL effectively ~3.33K? To Reproduce Steps to reproduce the behavior:

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[berryPiTech]

Bvernham raises a valid point. To avoid reducing the effective RL, the second voltage divider (for level shifting down from 5v to 3.3v) should employ high impedance.

A 100k/200k combination would be better than the (1.7k/3.3k) combination in the diagram.

I have verified the 100k/200k combination works fine for esp32c3.

[miguel5612]

Closed due to clarification. As noted by @berryPiTech, the concern about reducing the effective RL when adding a voltage divider is valid. To avoid this issue, a higher impedance voltage divider (such as 100k/200k) is recommended, rather than the (1.7k/3.3k) combination shown in the example. This approach has been tested and works well with ESP32C3. Thank you for raising this point.