I'm a noob! Which battery?

ok so i bought a laser module from laserlands thats a 120mw 780nm. It also states 5vdc. 'm pretty sure that means 5 volts dc power. Anyways, looking at the beam through my digi camera that has the ir lens removed the beam would be bright for a second then it would fade out. I had the laser hooked up to a 2025 3v lithium batter. Is it the battery that is causing this because its not 5v? Should i use different batteries? 2 AA's? Some 5v battery I don't know about? Thanx ahead of time for the help.

It is too small - it cannot supply the necessary current. Do you have any larger lithium cells? If not, try 3xAAs - close enough. 2xAAs might work, depending on how good the driver is.

It would be good to have a bench power supply so you can do lots of experimenting like this.

Check with markindallas I think he may be selling one.

ok so 2 AA's worked,but 3 AA's worked better. Thanks.