Button battery cells have an internal resistance that limits their current so the laser is not destroyed. A laser needs about 3V at about 40mA. Then the 4.5V worth of button battery cells have a total internal resistance of 37.5 ohms. Your 4.5V LM317 or 3 AA cells will burn the laser out.
if not then here it is again, THERE IS AN ADDITIONAL (current limiting) RESISTOR right behind the laser diode, there's no need for any other components (well at least for the laser pointers that I have)
Then simply look at the polarity of the battery cells to see which wire of the laser is positive and which is negative. The on-off switch will be in series with one of them.
Yep, i tried the 3AAA batt approach and it worked......until the laser burnt out! I would take audioguru's advice, unless you know the value of the resistor, the one on mine was blank and sealed into the plastic case so i had no way of finding its value.
Hee, hee.
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Yep, i tried the 3AAA batt approach and it worked......until the laser burnt out! I would take audioguru's advice, unless you know the value of the resistor, the one on mine was blank and sealed into the plastic case so i had no way of finding its value.