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dc power supply question


New member
Oct 7, 2008
dc power supply question

I have been trying to make my green 5mW DX lasermodule to work by outern power source so I wouldn´t need batteries.
I have this regulated dc power supply 2000mAh.
I broked one module because something heated up very fast in its driver while power supply was in position 3v.

It works great with diy bluray-pointer with rksctr driver in 7,5 or 9v.
Allso works great with DX Genuine New Wish 5mW Red Laser Module with 3v.

I have tried this 3v setting with all my 5mW greens and all became very hot quickly, but didnt get broke because I disconnected the wires fast.
I measured that output with multimeter and it was like 3,15v.

Do anybody have any ideas why it dont work with greens?
Is it about the dc power supply 2000mAh?
And why it works with red and bluray?

I would like to make some kind of labbies out of those lasers and use them without batteries.

This site has been great fountain of knowledge for me about lasers.
Im still just a rookie in this interesting hobby.
So if you have any ideas I will be gratefull.


Now to sleep because it is 0:15 am here in finland and to work early in the morning, so I cant answer to you untill next day if you want something precisely details.


Well-known member
Oct 26, 2007
Re:  dc power supply question

So those "regulated" DC power supplies are only regulated insofar that they use a regulator and their output is relatively steady. Their output can vary depending on the load or the way it was put together, etc. Basically, it assumes that your device needs at least 3V, but can handle more if necessary, which is a good assumption for most devices. The problem, for you, is that some green laser drivers, because they're so cheaply made, are affected by the input voltage. If it's too high, there'll be excess output, too low, and the diode will be starved. It's probably why they're so easily pot-modded.

What I would do is get a true regulated power supply (i.e. YOU know what its regulated output is), such as this power supply from Sparkfun.

What is that? It outputs 5V or 3.3V? Well just replace the switch with a pot and you'll have a fully adjustable power supply. I've done it myself, and it works quite nicely.