Why put a diode in parallel to a relay?

Hello Jumart,

Thanks for writing in! It's generally a good practice to connect a diode in parallel to a relay, it helps to prevent large voltage spikes, they can result in an electrical arc and destroy switching transistors or other devices connected to the relay. This diode is also known as 'snubber diode'.

Hope that helps,
Elizabeth

Elizabeth is correct.
It is also know as a Back EMF diode which discharges the relay coil energy when power is removed from the relay coil.

Regards
Don

OOOOHHHHH Undesrtood! Amaizing answer!
I never found out why this is used. now I know
If so, I think I know why my previous circuit was damaged. The diode was missing! :)

Thank you Elictro.
Amaizing library, I love u SnapEDA hahahaha