Thank you. I have a pic but my phone wont upload it? Ok..i have an ldr set up off a 9 v. This triggers the relay when I cover it. I want to run the automata off a separate power source, which the relay will start. I'm not sure how to wire the 3v separate battery source and motor into the circuit ? I'll try and upload a diagram to pc later...see if that'll upload to here?
That is a little clearer actually... let's see if I got this right.
You have a 9V source and LDR which you want to use to trigger an automata that runs off a seperate 3V source. If this is the case, easy!
The relay has two sides:
-Coil Side : This is the side you energize to make the relay switch. There should only ever be 2 terminals for this.
-Switch Side : This is the side that does the actual switching, and is not electrically connected* to the Coil Side. There can be anywhere from 2 to 6 terminals for this depending on the type of relay.
For your project, you would simply use 2 of the Switch Side terminals. I will throw the technical term at you, if you have trouble let me know. If there are more than 2 terminals on the Switch Side, you want to use the 'Normally Open' pair. This pair will connect when you energize the Coil Side. (That click you hear
)
To determine which side is normally open, and normally closed, you can test with a multimeter. If there is continuity (a very low voltage) than the pins you are testing are normally closed. Now, you should power the relay Coil, and test the pins again. You should find that the normally closed pins are no longer connected and that one of those pins is now connected to another. This NEW pair is the normally open pair. Alternatively, if you share the part number of the relay, we may have a diagram we can look up.
This new pair will function almost exactly like a normal switch, and can be put between the 3V power source and the Automata.
*Always a good idea to look at the spec sheet for the relay, I have not yet seen a relay where the coil side is connected to the switch side
internally, but I can't guarantee they don't exist! This
could make wiring more interesting.