Laser wont work ...?

Question

i took apart my airstrike 600 air pistol because i wanted to take the laser out of it.
i took it out but now it wont seem to work and i think before that when you held the trigger down a bit the laser activated.
the gun took 4 aaa batteries but now i cant get the laser to light up using the red and black wire on a battary. does anyone know how i can get the laser to work?
thx

Answer 1

First of all, you will not be able to light a red laser diode with a single 1.5 v battery. The forward voltage drop of most of these types of laser diodes is upwards of 2 to 2.5 volts, so you would need a minimum of 2 batteries in series with a series resistor to get it to light up by itself.

The specification sheets that I just looked at called for several 10s of milliamps (20, 30, 40, depending on the power level) to operate the diode. To be safe at 20 mA, you can connect 2 AA batteries (3 volts) in series with the diode and a 33 Ohm 1/4 Watt resistor. That should give you some light from the laser diode to see if it is 'good', or not.

Be careful that you don't overpower the diode and overheat it, because it can burn out very easily. Also, be careful that you don't accidentally reverse the battery leads, because the reverse breakdown voltage is only about 5 volts and you can damage it that way, too (if you have, like, 4 AA batteries in series with a larger resistor and the diode).

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