ESP32 pins difference between VIN and 3V3 pin

[brownekos123]

Hi, I have this ESP32, can please some explain to me the difference between the ESP32 VIN and 3v3, from what I understand the VIN is for inputs only, but I powered a 4 relay module with that when I plug it with an micro-usb, is it normal ? Can it effect my esp32 on the long term ?

I just followed this tutorial : ESP32 Relay Module - Control AC Appliances (Web Server) | Random Nerd Tutorials and they link the vcc to the vin, aren't we supposed to do 3v3 to the vcc ? and use a different source power and link it to the VIN to power my esp32 when USB is not here anymore ?

Thank you very much for your time ,

[MaximoEsfuerzo]

Vin is connected with +Vusb through a diode and is the input of the 3.3V regulator, so it is taking power for the relays from the USB port.

[gilshultz]

I do not know this board but Vin is generally a 6-12 volt input which the onboard regulator would change to either 5V or 3V3 depending on the processor. Some boards will add a second regulator to step the Vin to 5V and that to 3V3. The best solution is at look at the schematic.

The USB supply's 5V power which the onboard regulator adjusts to 3V3 for the processor and applies it to the 5V pin.

[brownekos123]

Thank you very much, it helps a lot

[brownekos123]

Do you know if I can put directly 5V on the VIN without being worried ? Or it's too risky ?

[gilshultz]

@brownekos123

if I can put directly 5V on the VIN

You can do that on many of the boards but I do not know your board so you will have to look at its specifications or a valid schematic.