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power supply?

A

anrchy

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What if one were to take a power supply that outputs 5V and 300mA and wire it directly to the diode, wouldn't that be the same thing as using a driver?

What is the max amperage you could push with a PHR-803T diode?
 





The power supply needs to be regulated or you risk damaging the diode. It's recommended to use a driver to minimize risk. 100-130mA is good for a phr
 
you might want to get a multimeter to make sure its actually up to spec. if you're talking about the things u plug into the wall. all of the ones of that ive tested are 2V over rated n the mAs are so high the multimeter wont read it
 
I READ the faq btw...

So how do you figure how many mA any given diode can handle? And does increasing just the amount of mA necessarily increase the wattage output of the laser?

From what I have read it looks to me that you don't want to supply more than 5V directly to the diode. But wouldn't you want to increase the voltage once you pass a certain amount of amperage? Or does it not work that way?

I want to build a "Plug In" laser. I do not want to use batteries. I understand that you need to regulate the voltage and amperage. Is there a graph that shows the power output in mW and what the voltage and amperage setup for those are?

100mW - ?V - ???mA ect...

Thanks for the help
 
No one really knows how much current a PHR-803T can take. Actually no one knows the max current of the GGW,SF, and BDR. We do not have any spec sheets for any of those diodes. All of our "safe" numbers are from hundreds of diodes dying to the hands of our members to allow us a small amount of understanding for these diodes.

-Mike
 
cust11 said:
No one really knows how much current a PHR-803T can take.
Click to expand...

I do . . .

BWAAAHHAAAHHAAHAHAHAHAAAHAAHAAHAAHAAAaaaaaa . . . . . . . .
:eg:


Sorry -- I'm better now :angel:

Peace,
dave
 
ok... so has anyone here built a plug in laser? If so, how did you go about it?
 
You can buy regulated wall warts that actually output the rated voltage as opposed to normal wall warts that output more than what they are rated for to compensate for the voltage drop they experience when they are put under load. But for the sake of laser diodes, no power supply is perfect and are still susceptible to surges and spikes. A driver is again, a necessary component to the long- term well being of laser diodes.
 
Wall warts are never to spec. Some i have tested that claim to be 9V or 12V have pushed as much as 15V under a light load. Best to use a proper driver
 
anrchy said:
ok... so has anyone here built a plug in laser? If so, how did you go about it?
Click to expand...

Lots actually. What you want is a laser module: A laser diode with a driver in a case with a focusing lens. Lots of people in the BST sell them. Ask for pig tales (means bare wire leads) or some come with 9V battery clips. Then, instead of using batteries (as for a pointer), wire the leads to a wall wart that is rated at what you want. Just make sure the voltage and current are what you need. I wire a switch too.

This being a "laserpointerforum", most people are not interested in "plug in" type lasers; they are not mobile.

For instance, I bought a laser module from dave (nice post above, btw! A moment of silence for the dearly departed.) and used a wall wart from Goodwill to power it. Works great. I recently bought some of these: aixiz.com StoreFront and they are rated at 3.2V. So, I picked up some transformers rated at 3.2V.

Does that help?

Kristopher
 
anrchy;

I have used a 5 VDC switching wall wart to power a PHR-803 @ 125ma.

Switching supplies have 115-230 VAC inputs & are usually well regulated.

Most 5 VDC switching supplies output about 5.1 to 5.2 VDC.

This is pretty close to the ideal PHR-803 voltage requirement for 125ma.

I would use a low value resistor to set the current slightly lower than you want.

The laser diode must be in a good heat sink, or as it heats up, the ma will increase at the same voltage.

LarryDFW
 
Last edited:
Enjoy your fail-laser. Seriously DO NOT try this. Each diode is different and thus have different voltages. Also if you happen to be lucky and have a 5.1v diode at 125mA or whatever, thermal runaway WILL kill the diode even with a heat sink. Even if the diode temperature would (miraculously) be constant, the power supply can still change! Use a driver and read the FAQ. Now I said it twice.
 
FireMyLaser;

I have been running several PHR Blu-Rays on fixed voltage for several months now.

Have not damaged any of them.

With the resistor, you can set the starting current @ 100 ma.

Then let it run for 5 minutes in the heatsink and recheck the current.

LarryDFW
 
Yes with a resistor it is somewhat forgiving. But the tolerance is so low when you limit the 100ma current @5v that a different voltage drop of just 0.1V in the diode will increase the current with another ~100ma!
 
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