Mainboard heatbed command MOSFET

Vertex 3D Printer Vertex - Wiring and electronics
1

Hello,

For my 24V heatbed, I use a 18V 10A mechanical relay as power expander.
It works great and requires less than 20mA, which is I guess within the capacity of the mainboard ?
Does anyone know if there is a protection diode for the MOSFET on the main board ?

Thanks !

2

Nope, there is no protection diode.
So you better add one to be safe.

The Heatbed Mosfet can easily deliver way more than 8 Amps, so your “tiny” relay coil is no noticable load. :wink:

3

Ah thanks, I will do so :wink:

4

Just remember (if you not already did so) to put a current limiting resistor in series with your relay coil.