Hi
Is the esp32-PoE Board compatible with those cheap passive 12V/24V Poe Injectors advertised as "for 802.3af applications"?
Thanks
ESP32-PoE should work with passive PoE injector but it will not get powered by 12V/24V over the Ethernet. It requires higher voltage, so a 48VDC injector is an option.
Of course, the best practice is to use 802.3af approved or compatible injector - there is more than just powering in the specification like powering negotiation and more. Using injector that meets the standards would extend the life of your network equipment and hardware.
You should also refer to the datasheet of the chip handling the PoE in ESP32-PoE:
https://www.silabs.com/documents/public/data-sheets/Si3402-B.pdf