Why Did My Laser Pointer's Beam Dim So Quickly?

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SUMMARY

The discussion centers on the rapid dimming of a 5mW, 650nm laser pointer powered by AG-3 button cells. Users observed that the beam brightness diminished significantly within 30 seconds of use, contradicting the advertised battery duration of 3 hours. The issue was attributed to the inefficiency of the laser diode and the low voltage of the AG-3 cells, which are indeed 1.5 volts, leading to a quick depletion of power. Comparisons were made with other laser pointers, highlighting that red lasers typically have longer operational durations than green lasers.

PREREQUISITES
  • Understanding of laser pointer specifications, including power output (5mW) and wavelength (650nm).
  • Knowledge of battery types, specifically AG-3 button cells and their voltage ratings.
  • Familiarity with laser diode efficiency and its impact on performance.
  • Awareness of differences in operational durations between red and green laser pointers.
NEXT STEPS
  • Research the efficiency of laser diodes and their power consumption characteristics.
  • Investigate alternative battery types for laser pointers that provide longer usage times.
  • Learn about the specifications and performance of different laser pointer colors, focusing on red versus green.
  • Explore consumer reviews and testing of laser pointers to assess real-world performance against advertised claims.
USEFUL FOR

Laser enthusiasts, product reviewers, and anyone interested in understanding the performance and specifications of laser pointers, particularly in relation to battery life and efficiency.

hl_world
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I got a 5mW (class 3A), 650nm laser pointer yesterday and it came with 3 AG-3 button cells and over a day, it was on for about 60 seconds, maybe more however I noticed the beam wasn't as bright as it was when I first put it on. Over 30 seconds worth of use, it seemed to dim further until I replaced the batteries with some AG-3s that came with another product and it was noticably brighter. The 3mm white LED wasn't affected.
The website I ordered it from said its battery duration was 3 hours (it's the 2 in 1 at the bottom). It also said it came with 3 2.5v watch batteries (I thought AG-3 cells were 1.5 volts).

Why did the button cells lose their power so quickly?
Why do the AG-3s cause the laser beam to dim instead of allowing it to be at a constant intensity?
Did the website get the facts wrong?

Thanks for any replies
 
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Does the advertisement tell you about the intensity of the beam for the continuous three hour duration?
 
No, but we're only talking about roughly 90 seconds for the beam to half its brightness at this rate, the beam will dissipate by 5 mins not 3 hours.
 
The advertisement is a lie. I have laser pointer running on two AAA batteries and it lasts for less than ten minutes. The laser diode is simply a power hog, inefficient at that.
 
Thanks for your help.
 
Red laser pointers last longer than green ones .
 

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