I've been looking into reverse polarity protection and come across a lot of resources that recommend using a P-channel MOSFET with a Zener diode.

Every single one of these circuits shows the MOSFET reversed - as if current was flowing from drain->source, when in reality the current in P-FETs flows from source->drain.

Some of the articles even have a comment that echoes my confusion. Am I actually missing something here or is there some reason why all of these circuits seem incorrect?

A few examples:

* [This one](https://circuitdigest.com/electronic-circuits/reverse-polarity-protection-circuit-diagram)

[![enter image description here](https://i.stack.imgur.com/L7ztr.png)](https://i.stack.imgur.com/L7ztr.png)

* [That one](https://components101.com/articles/design-guide-pmos-mosfet-for-reverse-voltage-polarity-protection)

[![enter image description here](https://i.stack.imgur.com/S7b2V.png)](https://i.stack.imgur.com/S7b2V.png)

* [This other one](https://hackaday.com/2011/12/06/reverse-voltage-protection-with-a-p-fet/)

[![enter image description here](https://i.stack.imgur.com/tQpWS.png)](https://i.stack.imgur.com/tQpWS.png)

If these circuits **are** wrong, then I assume it's more than just the MOSFET being reversed, and the Zener diode should still be between the source and gate. Is that correct?