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ArcticMyst Security by Avery

Laser diode protection circuit.... is this ok?

Zom-B

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Joined
Mar 25, 2008
Messages
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Points
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Hi I'm new here and I have a question, since you guys seem to know a lot about these things.

Some background: [skippable]
I got a bunch <5mW red lasers, and the AG13/LR44 batteries were empty in no time. I saved a few batteries in case I want to be mobile and otherwise connected the lasers to a lab power supply. After a while the LD's got blown because of initial switch-on/off spikes or accidental overvoltage. My temporary measure was to leave the power supply on day and night, not touching the voltage knob, but eventually people in my house thought it might save power if they turn it off and then I keep forgetting to pull the cords out before turning it on again. I think one might even have died just by plugging in the cord at the correct voltage, but with multiple too steep start-up slopes (as a result of grinding metal plug against the metal socket).
[/skippable]

Since I got tired of getting my LD's blown, I took my last working one and fixed it with what I think, a protection circuit to protect from overvoltage, voltage spikes, reverse voltage and maybe even smooth the start-up slope. My question, is this circuit adequate for my requirements. If not, what would be better?

hmm, why do I get an error when including an ? Trying the too high compressed attachment...[/s] i need 10 posts[/size]
 

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Joined
Jul 8, 2007
Messages
530
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Looks like a good start. You've added a filter cap and reverse polarity protection (??)

As you've found out LDs have unique power supply requirements. There can't be any spikes or transients, which can often occur when you first turn on an otherwise good supply. Sounds like what you've got should help (certainly for a < 5 mW red), but you also might want to consider a different supply.
 




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