Overcurrent Test

Hey everyone.

I just took apart a DVD player, which, oddly enough, actually had two LDs in it, one of which was in fact a *red* diode (not IR, it was pretty bright and was about to last at around 60mA), and I decided to do some tests.

The first test was to see how much current the red one could handle. Unfortunately, it died on me at about 100mA, but that's no biggie. Was from a cheapo DVD player that I didn't even expect to have a nice LD in it.

But, after that, I just wanted to see what would happen when I cranked up the amperage on the remaining diode (I suspected this one was IR, was very dim, but may just have weakened it due to overdriving).

So, I hooked it up to, essentially, my LD play box (adjustable current from 50mA to 1.25A via large knob), and, starting at 50mA, quickly turned the knob to 1.25A... and I saw a white flash.

Of course, it died immediately, but there *was* a white flash that was emitted from the diode... may have been yellow? Not entirely sure. Anyway, anyone know about this? It's interesting, because it went from extraordinarily dim to significantly brighter for a bright instant, and the light was white, then it went off forever.

Any thoughts?

murderer :gun:

^ The flash may be due to the fusion of the thin wires that connect the chip to the pin, probably ..... like in a lamp, when you burn it for overtension.

Is there a hole in your wall? maybe you discovered how to make a laser gun / ammo.....

unfortunately, no hole in the wall =p But that would be really cool.


@HIMNL9: That's possible. Never thought of that though.

HIMNL9 said:

^ The flash may be due to the fusion of the thin wires that connect the chip to the pin, probably ..... like in a lamp, when you burn it for overtension.

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I have seen a nice flash too, it was when cutting a 220V cable I thought was dead.

I sometimes take my microwave oven transformer ( 2kV ~ 2 Amp ) and just slide the wire over a old circut board , that makes interesting little explotions and lots of nice colored lights from exploding transistors and stuff like that.

i just say that the light from that diode was pure terror lol

2kv, 2amps? That's like 4000w. I don't think I have ever seen one above 2500w, usually they are like 1100 or 1500. Did it come from some kind of industrial microwave or something?

Yeah, it was probably crapping it pants. After all, it got probably 100x what it's used to. Anyway, out of that old DVD player (writer, too?) I got a copy of Shrek the DVD! So not a bad result.

benmwv said:

2kv, 2amps? That's like 4000w. I don't think I have ever seen one above 2500w, usually they are like 1100 or 1500. Did it come from some kind of industrial microwave or something?

Click to expand...

Did you ever heard of magnetic saturation - impregnation


That means you can OVER-load a transformer shortly ( and with shortly i mean till it heats up almost starts to smoke )

And a transformer can give much much more power than it's rated power output

I had a nice flash when I accidentally touched two leads of a 12V UPS battery with a wrench while tightening down the bolts. It melted some of the metal.



I'm sure this is very relevant to the topic.

Vaporized gold bond wires. 'nuf-sed.

And BB, nicely done

That's cool sounding =p

Hey, and not to get off topic... but why is it that my alligator wires don't want to be used to charge an 18650?

Contact resistance or even resistance on the wires themselves?

Some battery chargers require a really good connection to the battery as they use pulses of current to charge them, but also pulses to discharge them in order to test if you connected the proper type of battery. I'm not that sure about lithiums, but for nimh cells this is very common.

Yeah, looks like the resistance for my alligator wires is about .4Ohms... probably enough to screw things up.