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SenKat's diodes wattage?

Lee

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For the longest time everyone has been saying Senkat's diodes are 200mw or 250mw... However, I also read on this forum (forgot where) that the 200mw range is pulsed, not constant. I read the constant wattage is around 80mw. So what is the true (constant) power of a Senkat diode?
 

Lee

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Yes Gazoo, I saw the data sheet before I bought the diodes. I have already completely built the thing into a dorcy flashlight (it looks really nice, pictures later) and I know the pulsed wattage is 250mw. The question remains, what is the constant wattage of these diodes?
 

Gazoo

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resaL said:
Yes Gazoo, I saw the data sheet before I bought the diodes. I have already completely built the thing into a dorcy flashlight (it looks really nice, pictures later) and I know the pulsed wattage is 250mw. The question remains, what is the constant wattage of these diodes?
To calculate the electrical wattage you would take the volts times the amps. But I don't know why you would need to.

The constant optical output is 80mw's. This is running the diode with 130ma's at appx. 2.5 volts.
 

Lee

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Ok, I use a CR123A (3V) plus a little driver curcuit... thx for the info... I need to know the output for bragging purposes, what to label the video and all that.

roSSco said:
Don't forget YMMV.  :D
?
 

Gazoo

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Looks great. To determine the power you would need to measure the current going to the diode. Be very careful if you do this. The following graph Hemlock Mike made should help. The plot with Sony GB next to it is what you want to look at. The other line represents an open can diode.
 

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Benm

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I've made circuits for pulsed operation, but it will do little good for average power output.

Pulsed operation is useful only if the power vs current curve is above linear, but these diodes tolerate CW operation also in the area the curve starts to level off. Pulsing for an average current would then only result in a lower average power output.

Working in pulsed mode has some other intesting effects though, such as a constant beam pattern regardless of duty cycle. But as long as you only want to burn holes into stuff, CW operation is fine.
 

laserrod

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Benm
Working in pulsed mode has some other intesting effects though, such as a constant beam pattern regardless of duty cycle. But as long as you only want to burn holes into stuff, CW operation is fine
I read that pulsed laser light reduces the speckle patern that is observed to move opposite of eye/head position. I assume above you meant the dot guasian power dot size. ( round, round with a line, etc..)
Do you find that speckle effect reduces as compared to CW readiation?

Thanks for your previous info too.


DGM
 

Benm

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I read that pulsed laser light reduces the speckle patern that is observed to move opposite of eye/head position. I assume above you meant the dot guasian power dot size. ( round, round with a line, etc..)
Do you find that speckle effect reduces as compared to CW readiation?
I dont think it makes any differnce as far as speckle pattern is concerned. That depends more or the surface you shine on than on the power level of the laser. It might be reduced in case you pulse it so hard it's loosing coherency (borderlining on modehopping).

What i mean above is that when you vary the current to a laser diode linearly, you usually can see some shifting in the output pattern (when you shine it onto a wall without any lens this is most visible). When you vary power by changing duty cycle but with constant pulse current, you don't see any changes in beam pattern, just in intensity.

Especially at lower levels the beam pattern of LD's is often pretty bad, just above treshold is a good example. In that case you can make a better beam by pulsing it at a good current (near rated power) but at a low dutycycle.
 

Lee

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Kenom said:
What resistor are you using with yours??  cause even using larger resistors the least I've gotten with the dorcy is 120mw.  Based on what resistor your using I can tell you what your laser is putting out.
I am using two 5 ohm resistors in parallel.
 




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