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How did i Kill my Diode

bennett326

bennett326

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i really dont care then go hook up your other diode to 2 D batteries im sure it will work...........:facepalm:

if you wont accept the reason why it blew than dont ask your wasting peoples time
 
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T

Things

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Direct driving is never a good idea when your diodes Vf voltage is so close to your batteries FULLY CHARGED voltage. Anyway, like I said, direct driving is usually fine (Though not ideal at all), but you NEED some form of current limiting. As simple as a resistor. Calculate the total charge voltage of your batteries, so for a single Lithium battery, it'd be around 4.2V, and calculate a resistor like you would to connect an LED to it.

Use this if you get stuck: LED series parallel array wizard

Treat your laser diode as if it's an LED, since well, it basically is.
 
justinjja

justinjja

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Tech_Junkie said:
Yes, and no. They dont always work. As good practice its always better to use a driver so you dont run the risks of frying the diode, and red diodes are the only diodes I've seen that can work with direct connection.

But, just because one of yours worked doesnt mean it will work all the time.
Click to expand...

thats why i said "under the right circumstnaces" ;)
along with running one of the new mitsubishi 635nm diodes off 2 d cells (my build)
it is also pretty feasible to run a 445 directly off of a single 18650.

Things said:
Direct driving is never a good idea when your diodes Vf voltage is so close to your batteries FULLY CHARGED voltage. Anyway, like I said, direct driving is usually fine (Though not ideal at all), but you NEED some form of current limiting. As simple as a resistor. Calculate the total charge voltage of your batteries, so for a single Lithium battery, it'd be around 4.2V, and calculate a resistor like you would to connect an LED to it.

Use this if you get stuck: LED series parallel array wizard

Treat your laser diode as if it's an LED, since well, it basically is.
Click to expand...

Direct driving can be inefficient with a resistor, but if it works out that you dont need one, then it is ideal, better than any driver too.
example

edit:
sorry this has kind of gone off topic,
as i mentioned earlier i will be using a driver adventualy,
and as Things explaind the spike wouldnt nessasarly have to instantly kill the diode, but rather damage it, causing a failure shortly after.
 
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Tech_Junkie

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justinjja said:
it is also pretty feasible to run a 445 directly off of a single 18650.
Click to expand...

Its also very dumb. I guess if you had the money to throw away $50 diodes trying it it wouldnt be a problem. In any event a driver also gives you control, and better battery configuration options. So in all a $6 investment is logically a smarter option.
 
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T

Things

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Yes, but your success direct driving relies on your batteries. It might work fine on 1 set of batteries, but then you may get some new batteries with much lower internal resistance, and POP goes your diode. Much much better to just use a driver, or a resistor at the least, and save you ripping open your host all the time to replace the diode.
 
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Sigurthr

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Not to mention that as your battery's capacity gets used up it's output voltage will drop below the diode's Vf and your laser will putter out before using up the last of the battery's juice. So much for efficiency.

Hey, it's your money to do with as you please, just don't complain about it while continuing to justify it.

Hopefully anyone else reading this who might be new will learn from this.
 
justinjja

justinjja

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Sigurthr said:
Not to mention that as your battery's capacity gets used up it's output voltage will drop below the diode's Vf and your laser will putter out before using up the last of the battery's juice. So much for efficiency.

Hey, it's your money to do with as you please, just don't complain about it while continuing to justify it.

Hopefully anyone else reading this who might be new will learn from this.
Click to expand...

A very good point for a 445 direct drive,

However the midsubishi 635nm diode im using in my build can operate below 2v, the point at which a pair D-cells are basicly completely dead.
 
Tech_Junkie

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justinjja said:
However the midsubishi 635nm diode im using in my build can operate below 2v, the point at which a pair D-cells are basicly completely dead.
Click to expand...

But if you used a boost driver you'd still get full power from the diode till the batteries finally diminished.

I dont get why you keep arguing the non-driver issue. Your question has been answered numerous times by people who have forgotten more information than you'll probably ever know. If you are trying to look smart, you're failing. If you're OK with no driver, fine, but stop arguing the point that its OK, because its not. Using no driver limits your configurations, and has a high chance of frying your diode. All your arguments wont change that fact. And at $6 its just stupid not to. You've already thrown away that much on the diode you fried. I dont get your problem with excepting this.

I'm out. Go argue with someone that cares. We tried to help you. If you're too dumb to listen then its your own problem, not ours.

Good luck.
 
justinjja

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Tech_Junkie said:
But if you used a boost driver you'd still get full power from the diode till the batteries finally diminished.

I dont get why you keep arguing the non-driver issue. Your question has been answered numerous times by people who have forgotten more information than you'll probably ever know. If you are trying to look smart, you're failing. If you're OK with no driver, fine, but stop arguing the point that its OK, because its not. Using no driver limits your configurations, and has a high chance of frying your diode. All your arguments wont change that fact. And at $6 its just stupid not to. You've already thrown away that much on the diode you fried. I dont get your problem with excepting this.
I'm out. Go argue with someone that cares. We tried to help you. If you're too dumb to listen then its your own problem, not ours.

Good luck.
Click to expand...

Actually boost driver would kill the diode faster than direct drive, you would actually need a buck-boost driver. I'm sure you knew that at one point, but have since forgot. considering you have forgot more info than i will ever know :p

I have mentioned several times that i will be using a driver with my build.
Im really not trying to argue, just having some fun.
 
bennett326

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face-palm-e1294657839590.jpg


a driver isnt gonna kill your diode faster than direct drive :wtf: direct drive will most likely kill it instantly if you set a driver to a safe current it will live a long happy life
 
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Zlasersinc

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I have been here for a year and a half but just made a account. Thanks for the rep :) :beer:
 
justinjja

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bennett326 said:
a driver isnt gonna kill your diode faster than direct drive :wtf: direct drive will most likely kill it instantly if you set a driver to a safe current it will live a long happy life
Click to expand...

A guess you dont know what a boost driver is: Wikipedia
A boost driver is only able to increase voltage
 
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