Comments on: LED Forward Voltages

By: Ed

Ed — Wed, 26 Dec 2012 16:40:47 +0000

just going to be one of those mysteries

Nothing that can’t be explained by a total screwup: it certainly wouldn’t be the first time I’ve measured something that wasn’t there. [sigh]

Mostly, I’ve been poking those LEDs with a long stick, waiting for something to leap out at me. Hasn’t happened yet, so I may actually be forced to build something. After I finish pestering them for more data, of course…

By: madbodger

madbodger — Wed, 26 Dec 2012 16:22:01 +0000

Over the last half-year, I kept hoping for an “aha” moment explaining the bizarre I/V behavior of the strings. Plenty of entertaining reading on how to to generate and plot the curves, and plenty of data on LEDs from those bags, and I didn’t see anything unexpected in it. I suppose this is just going to be one of those mysteries. Granted, I haven’t bothered trying to assemble a pessimal set of data from the plots and trying to regenerate the conditions above, but since the data looks well-behaved, I don’t think that would work anyway.

By: LED Curve Tracer: Hardware « The Smell of Molten Projects in the Morning

LED Curve Tracer: Hardware « The Smell of Molten Projects in the Morning — Tue, 24 Jul 2012 11:55:31 +0000

[...] on that comment and faced with two sacks of LEDs, I thought an LED curve tracer might come in handy at some point. [...]

By: Ed

Ed — Fri, 13 Jul 2012 12:08:47 +0000

Trust me: that thought never crossed my mind… [grin]

I can still assemble a complete radio from the parts, which could be a Good Thing.

Back when the ICOM Z-1A HTs still had functional battery packs and I didn’t realize how delicate their jacks were, we would sometimes ride to a public service event and turn into pedestrians-with-a-radio. The Wouxun has lithium cells that should last longer and the jacks have a protective plug plate, so maybe that’s less of a terrible idea than it was with the ICOMs.

By: david

david — Thu, 12 Jul 2012 21:23:29 +0000

Did you ever consider whether you might not be better served selling the Wouxun batteries to someone who actually needs them on Craigslist and using the proceeds to buy something standard and easier to work with? Less fun, I know. :)

By: Ed

Ed — Thu, 12 Jul 2012 16:07:09 +0000

tracing the I/V curves

As long as they’re not hand-plotted, count me in. I briefly thought about modifying the MOSFET tester, but, given the low currents and higher forward drops, I think a breadboarded one-transistor tester with cannibalized firmware is in order.

Must. Not. Build. Robotic. LED. Handler.

Dang, another project…

By: madbodger

madbodger — Thu, 12 Jul 2012 13:52:29 +0000

I’d probably try tracing the I/V curves of the two highest and two lowest voltage ones. Given the unexpected results of running strings of them, I’m guessing you’ll find at least one curve that isn’t like the others. On the other hand, I also have sacks of LEDs, I could do this too.