Relay shield


I just started playing with Arduino and processing for a school project. I bought a relay shield from dfrobot. And i didnt want to shortcircuit my arduino so thats why i come here to ask this:

I want to switch the power of a Showtec Par 30 on and off with the arduino. I will figure the code out but i have no idea to connect what cable to what port.

I have these ports: Nc1 com1 no1 ground and 9v. Could someone explain to me what they are and what cable to connect to what slot?

And another thing: If i have the shield on can i still use the 5v gnd and a0 from the board cause i will still need those to control a servo.

Hope you guys can help me.

Thank you in advance!

NC = normall closed NO = normally open C = common

When the relay is not energized C is connected to NC. When power is applied to the relay C is connected to NO.

So normally you connect the load to the power supply through C and NO.

You can use A0 and you can use 5V as well however normally you would power a large(ish) load like a servo from a separate supply, the Arduino 5V is not really designed to drive servos although it will probably work.