user18794: 
How to I connect the pins of one channel relay to control and led which is connected to pin 13 of an arduino uno.can you tell me the steps which pin will go to which pin

user19034: Wiring Diagram to Pin 13 for a single relay? This might help.


user20843: I believe that the Arduino ground should be common with the 12v source ground. I may be wrong, though that's the way it works for me. Also be aware that some of these relay cards work when the pin is LOW, others when the pin is HIGH. Mine energises when the pin is HIGH, though all tutorials I had read until the last had the relay switching on with a LOW pin. 

18794: <p><img src="https://i.stack.imgur.com/7CR3B.jpg" alt="I want to control an LED using a relay.." />
How to I connect the pins of one channel relay to control and led which is connected to pin 13 of an arduino uno.can you tell me the steps which pin will go to which pin</p>
 19034: <p>Wiring Diagram to Pin 13 for a single relay? This might help.
<a href="https://i.stack.imgur.com/BHVtF.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/BHVtF.jpg" alt="enter image description here"></a></p>
 20843: <p>I believe that the Arduino ground should be common with the 12v source ground. I may be wrong, though that's the way it works for me. Also be aware that some of these relay cards work when the pin is LOW, others when the pin is HIGH. Mine energises when the pin is HIGH, though all tutorials I had read until the last had the relay switching on with a LOW pin. </p>
