[Laser] pointers life XE2AT

[Andrew T. Flowers, K0SM]

Just to echo Jim's comments...
If you are going to use a cheap laser pointer that has only a 
current-limiting resistor, make sure you protect against power-on and 
power-off transients. I turn on the supply first, and then connect the 
circuit that actually has the laser on it.  I use the opposite process 
for turning it off.  So far so good.

Andy K0SM

Jim Moss wrote:

>Most laser pointers running on batteries are either 3 volts. The batteries
>generally last a few hours. But you will find the wavelength and power will
>vary with temperature and voltage.  I don't think you should find much problem
>with power dropping significantly in a few minutes.  You could use a bigger
>voltage and a voltage regulator to exclude battery voltage as an issue.
>
>The laser diode itself isn't really a voltage controlled device. It is actually
>current controlled.  That is why there are generally driver circuits.  Some of
>the cheaper pointers do not use drivers, but rather just use a current limiting
>resistor. There are dangers of damaging the laser device with instantaneous
>over current.
>
>With proper driving, laser diodes should work for 1000's of hours.
>
>Jim
>
>--- Alvaro de Leon Romo <xe2at at hotmail.com> wrote:
>
>>Another question is if the pointer need 4.5 volts to operate what happen if 
>>I use less power ?
>>  How many hours is the life of the pointers ?
>>  The pointers are less effective or bright after 5 minutes continue 
>>operation ? ( to found each other at long path )
>>   The pointer produce hot or we need some break time to permit the pointer 
>>cool ?
>>   I see after a long ON time the pointer is less bright and after 5 minutes 
>>its bright is normal again, I am using 3 volts..
>>Al
>>Thanks in advance
>>Ps my pointers is chain type
>>
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