Am a beginner to Raspberry pi GPIO (not to RPi).
I have brought a 12V 8 Channel relay and tried setting it up and later i found some issues.
I powered the relay with an 12V DC. My RPi is powered by another 5v 1A power source.
Then i connected the GPIO pins to the relay inputs,
As of now, relay were not functioning because only the gpio pins were alone connected.
Should i need to connect the ground of the relay to the GPIO in the RPi? Is it safe?