How to find out a relay's "trigger" voltage
I currently have several "old" (read: unused) relays laying around that I'd like to trigger using my Arduino Uno.
The issue with all of them is that they've got no datasheets available or if they have, I can't tell from the sheets at what voltage the relay triggers. Since they're all quite small and perfectly fit on a standard breadboard, I don't assume they would consume more than the 5V my arduino could provide.
I already checked the connections using my multimeter and there's definitely current flowing through the line it's supposed to run through when unenergized. The actual relay I'm talking about is an AZ8-1CH-24DE (http://www.digchip.com/datasheets/parts/datasheet/540/AZ81CH24DE-pdf.php).
Attached is the wiring scheme that's printed onto the relay.
And here's how I've wired the whole thing:
1 - +5V from Arduino (always on)
2 - LED1, which connects to arduino's GND
3 - LED2, which connects to arduino's GND
4 - arduino GND
5 - +5V from Arduino (control pulse)
I've also tried switching 4 and 5 around, thinking I inverted the two pins, but whatever I do, I can't get the relay to switch from LED1 being on to LED2 being on.
Would be glad if someone could help me out with this. I'm kinda new to the whole thing, but I though I understood how these things *should* work..
Also, if anyone comes to the conclusion that the relay will definitely need a higher (12V?) voltage to "trip", could you also tell me how I can control that relay from my arduino while only having my +5V pin from the arduino available? I thought about transistors, but maybe there's another way.