I have a connector which has the following lines:
- SDA (I2C)
- SCL (I2C)
The connector might get wet with water and I would like to protect the circuit from the resulting over-voltage in case the 12V line gets connected to the other lines.
Based on this schematic from this question Why is a resistor needed in zener protection circuit?:
I've designed this connector using a 3.6V zener diode and 330Ohm resistors. I don't understand why R1 and R2 are required and I've removed them in mine:
The connection would look like this:
Would this solution protect the connections from the 12V line? Is there a better approach?