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RussW

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Please forgive the newbie approach but I really do need help and you guys in this forum sound like you know what you are talking about.

Times have changed a lot since my days of garage experimenting. Radio Shack no longer carries parts you need. It seems that somebody has limited the sales of parts you really need probably due to safety or government regulation.

Anyway my questions. First, where is the best online place to buy a 445nm minimum 100mA diode and parts to build my laser. Second, do I really need a driver and why?

Thanks and I apologize,
RussW
 





If you're in the US, DTR (as GAtkins mentioned above) has nice diode, module, and driver sets in 445, 405, and 635. They are all pretty powerful diodes and might be too much for a first build, but since they are all self contained, they are ready to add to a host and make building very easy.

I have bought a lot of my parts and supplies from CajunLasers.com. Clif has some great prices, super customer service, and some of the fastest shipping around. He sells hosts, batteries, diodes, and most importantly... eye protection. Clif also sells some lower powered 405nm and 660nm diodes that work great as first builds.

Drivers are necessary to supply a constant current to your diode. There are cheap and expensive drivers (you can find a lot of information on the forum regarding types and what you get for your $). It's important to select a driver that will provide the current necessary to drive the diode you select with whatever power source you're going to use. You can even build your own driver with parts from Radio Shack (search the forum for LM317).

Most important is to invest in good eye protection that is appropriate for the wavelength you are using. Its way too easy to do real damage real fast.

Hope this helps.
 
YES YOU NEED A DRIVER.

The reason is simple: a diode looks like a short circuit to a an unregulated current power supply. The diode will gobble up as much current as you can possibly throw at it, which is why we run laser diodes on constant current power supplies, which really just limits the current to the amount we set.

Even if your power supply can only supply enough current for the diode to run without frying, you'll fry your power supply without a constant current driver, because it will be operating at 100% capacity, and no electronics are designed for that for long. Plus, there are instantaneous events that happen in unregulated power set ups that can fry a diode faster than a multimeter can respond to; you'll never even see the current surge or voltage spike but it will have already blown up your diode.

A second or so after the diode begins to lase it starts to build up heat rapidly, this heat makes the diode less efficient, and in turn the diode tries to pull in even more current, further stressing an unregulated power supply. Soon the voltage begins to sag and as the diode gets warmer it's required voltage rises as well. Now your diode is struggling to function and drawing more and more current as it gets hotter and hotter. This is call thermal runaway, and you can only prevent/stop it by using a constant current power source.

You can power any laser diode you can buy off a LM317 constant current power supply circuit that costs under $6 to build and consists of 3 parts (filter cap, current setting resistor, LM317). There is no reason to build a diode laser without a driver; doing so only wastes diodes that some other person would give their balls to have and enjoy, and it also wastes the time of everyone you ask for help from. (I don't mean you personally, just figuratively.)

Go with DTR. He's my go-to source for diodes, drivers, lenses, and modules (and pre-built combinations of those!).
 
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if you are new(like me) and you dont have experience i suggest you that buy a Just Add Diode (JAD) kit from Moh,

JAD from moh(link)

is the best way to buil a laser (445nm) and is cheaper than buy all the parts in diferent places you only need to buy a laser diode from DTR(link)

if you want to buil a laser a JAD kit is the best option for begginers

Note: Mohremberg (mohgasm.com) now is out of stock in JAD kits
 
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