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L.A.S.E.R. Answered

this laser says: 240mw pulsed, 100mW CW 5.6mm red laser diode does that mean that it's 240mW or 100mW? Should I install it in a 5.6mm laser module? if I were to hook it up to AAA should i just put a 1/4watt, 1.8 ohm resistor in series?

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NachoMahma
NachoMahma

13 years ago

. For very brief periods, it will handle 240mW. It will handle 100mW on a continuous basis. I'd call it a 100mW, but I'm not selling them. :) . The physical size/shape of the battery doesn't really matter - it's the volts. Not sure what value resistor to use - on the few LED projects I did, I used pots and turned them down until I got the brightness I wanted.

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guyfrom7up
guyfrom7up

Reply 13 years ago

I know the size of the battery doesn't matter, I was just asking could I put a simple 1.8 ohm resistor (determine by an LED calc) in series with it to power it. I'm just asking because I've never worked with laser diodes before and I don't want to break it. nice new avatar.

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NachoMahma
NachoMahma

Reply 13 years ago

. OK. It's been a while since I worked with Ohm's Law, so double check my formulas/figures.
. I = P / E
. P = 0.1W (100mW); E = 1.5V
. I = 0.0667A
. R = E / I
. R = 22.5 Ohms

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NachoMahma
NachoMahma

Reply 13 years ago

. R = 22.5 - (resistance of laser) Ohms

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guyfrom7up
guyfrom7up

Reply 13 years ago

I thought you just do this (I'm sorry, I forgot to put up what they said to do with it):
Voltage of LED = 2.8
milliamps: 190
Voltage source = 3.0v
3.0 - 2.8 = 0.2
0.2/.19=~1.05 ohms rounded up to 1.8 ohms

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NachoMahma
NachoMahma

Reply 13 years ago

. Hmmmmmm. You better get someone else to help. It looks to me like your calcs will work, but I'm not sure about the current limiting. . I don't think it will hurt to undervoltage the laser, so I'd start with ~100 Ohms and work my way down until it lased. Use your VOM to measure the current and adjust the resistor from there.