How to give supply to six lasers?

[baba786]

Hi,
Last night was working on my college project ,having some problems so want to discuss with you guys for the good suggestion.

I have six Infrared lasers ,specification of the lasers are given below.

1.Infrared laser wave length 780nm

2.Working voltage(3.2vdc,10mw each)

I have SMPS(SWITCH MODE POWER SUPPLY OF 18VDC)as supply for the six lasers.

According to my calculation I connected all the six lasers in series with 18 volt SMPS .After connection found that out of six lasers
only one was glowing (used Infrared camera).

Then for the further testing I took two Radio cell(D)1.5v each,and checked seperately all the lasers ,and all was working fine.

Now I want to ask that How I can run all the lasers using SMPS supply

 

[duffy]

Try using a resistor divider with the lasers, so each laser is in parallel with a low-value resistor (say 22Ω, 1/2W each). Put a 10µf or bigger cap across each, also. This will even out the voltage drops from differences in current draw on each laser.

Also, make sure your 6 lasers actually work at 3V (measured, not using stated voltage of flashlight batteries) or that your 18V supply is really 19.2V.