# How to Power a Laser Using Your AC Wall Outlet

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## Introduction: How to Power a Laser Using Your AC Wall Outlet

Hi Everyone!

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I've had a few people ask me lately about how to use an AC wall outlet to safely power a laser as opposed to batteries. I made a short video that shows you how to do it safely. It is a simple and practical video. There are many methods in which to accomplish this. I show you two of them in this video.

Thanks for watching! I hope you find it helpful.

Sincerely,

Patrick // www.engineeringshock.com

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## 4 Discussions

Shouldn't be laser powered with constant current source instead of constant voltage?

Voltage regulation here is key. Voltages over 3v can harm the laser. As long as the regulated 3v is clean (filtering/decoupling caps added) and can source a consistent 10mA or more, then this is a perfect solution. At least for a 5mw laser.

I'm afraid you're wrong. Current regulation is key here. Another key is the temperature characteristics of semiconductors. Of course your laser might work correctly with 3V, but it doesn't make it like this. Leds and lasers should be powered with constant current, because brightness depends on current. Of course current (when using just voltage regulator) depends on voltage too, but depends on resistance too. And resistance depends on temperature. And when current flows through semiconductor it's temperature rises. When temperature of semiconductor rises, it's resistance fals. When resistance falls, the current rises, rising temperature even more. Can you see this? Of course when you power your laser with just 3V it might be "almost" stable, but it's temperature rises, very slowly but still rising, allowing more current to flow, in the end burning out the laser.
When you're using the constant current source, it sets voltage according to the resistance to not allow to rise the current, when the temperarure rises.

I believe he was inferring that the way the regulator is wired, it is functioning as a constant current driver.