tried several diodes, nothing is powerful enough, what is the required current?

I harvested red diodes from 3 different DVD burners: a somewhat older Sony DRU-800A (fully closed diode, very similar to the 3-pin cylindrical cases I see in all HOWTO documents online), a recent 22x Asus DRW-24B1ST (diode enclosed in a cylindrical case, but open at the top) and a 22x LG GH22NS40 (weird half-cilinder case, the diode is entirely exposed on one side).

I've a current generator which I purchased online. It is capable of generating a constant current between 60 mA and 300 mA - this is confirmed by measuring it with a multimeter.

I tried all 3 diodes with this generator, throughout the entire range of currents. I could never obtain an "incredibly bright" spot. That's what all the tutorials claim - that the diodes should be VERY bright. They are not. They seem weaker than a regular 5 mW laser pointer.

I find it hard to believe I broke all diodes while harvesting them. I must be doing something wrong.

While feeding the diodes the 60 ... 300 mA, the voltage on the junction seems to be around 2.5 V usually, which seems okay to me. I never started feeding them the max current at the beginning, I always tried for the first time the lowest current, then increased it when the results were not satisfactory. I am certain they are being fed the correct current, I measured it by inserting the multimeter in the circuit while the diode was shining.

Any ideas or suggestions? I'm reluctant at this time to purchase yet another DVD writer, for fear of wasting money again.

Why don't you just buy diodes from a rep. source ?
You say they don't have a very bright spot, are you using a lens ?
all laser diodes need a lens to make a spot or dot of light !

Does that Power Supply "generator" need to be shorted out before connecting the diode? Does it measure, say, 7 volts open circuit? Your "generator" may be spiking the diode since it can't be turned to 0 (zero) volts. You need to be sure that your POWER SUPPLY is regulated down to nothing before you connect it to a laser diode.

HMike

It is also possible that your "current generator" is NOT smooth enough. If it gives any "spikes"' they could blow the diode in microseconds. You would NOT "see" the spike or measure it with your DMM, but it could blow the diode at first power.

Peace,
dave

Is it possible that you extracted the IR diodes?

Is the red you see really faint, or plush ruby red? Even at 80mA you should be seeing a decent output of red..

some pics of the setup may help...

In fact, pics of the diode, power source, setup, light emitted...

All will help for diagnosis.

Don't be put off just yet...

M

wannaburn said:

Is it possible that you extracted the IR diodes?

Is the red you see really faint, or plush ruby red? Even at 80mA you should be seeing a decent output of red..

Click to expand...

He described at least one open can red perfectly

Peace,
dave

daguin said:

He described at least one open can red perfectly

Peace,
dave

Click to expand...

Yeah I saw that.. The OC's are really delicate and could very well be dead. The other 2 are up in the air. Without pics, it doesnt hurt to check.

Wouldn't want him looking at that dull red LD thinking its red, just in case its not..