Can’t find positive terminal

[PIZAAA]

I bought this blue laser on eBay for a project and want to connect it to wires. I know the negative is the coil, but I can’t figure out where the positive is ? Any help ?

 

[paul1598419]

It would be helpful to see both sides on the driver PCB. I would not assume that the spring used for the battery terminal is negative. It could very well be positive. If I could see both sides I could probably tell you.

 

[RedCowboy]

Typically with Chinese dpss the spring is negative the case is positive ( the module body ) but you power it up at your own risk.

 

[PIZAAA]

Typically with Chinese dpss the spring is negative the case is positive ( the module body ) but you power it up at your own risk.

I’m not planning to power it up in any way I’ll still be using 2x AAA batteries (the batteries advised) but I need to make a different casing for my school project . I know I can solder the negative wire to the spring as I’ve seen it in videos but how would I solder the positive one on ? Thanks 4 ur help btw !!

 

[RedCowboy]

School project huh, you do know about laser safety and what you can and can't take into your school I hope, make sure that you do.

You could connect where the case pin on the back of the diode attaches to the driver board, they use the diode case pin to feed the driver from the battery tube body.

For your 405nm the spring as you said is negative and the body is positive feed through the case pin into the driver board, the center pin on the other side........ see arrow

 

[PIZAAA]

Laser Output Wavelength 405nm Output Power: 5mW Working Voltage C=3.0V

I’ll try that on Monday and get back to you, thanks !

 

[RedCowboy]

Most of those ebay 405's that say 5mw are actually much more, don't let the beam get into anyone's eye as it could do real damage even though it looks weak because we don't see 405nm very well.