Things about the Wallyworld light aka Brinkmann LED light

Soooo.... now that the Brinkmann LED light has been out for a while, has anyone suceeded in doping out precisely how it works? Or substituted components so that it is capable of delivering higher voltages or currents without melting?

I'm actually in the process of plotting out its schematics and was going to try and build my own, but hit a small snag. I can't seem to find anything about the transistors they used. It doesn't appear in any of my regular catalogs. Anyone know of a good reference manual (on-line or otherwise, though on-line is preferred) that lists different types of transistors and their equivalent?

BTW, did anyone measure the voltage across the LED in the Brinkmann? I got about 2.6V, but that can't be right? The LED should not be lit that brightly on only 2.6V.

Not a lot of answers, but one I can handle.

You get 2.6v measured because it is pulsing a higher voltage. You need an oscilloscope to get a true peak reading. Maybe could use a capacitor in parallel with the LED to get the average voltage there...

I'll have a look at mine and see if the transistors are cross refernce-able. From what investigating I did, it uses a NPN PNP transistor pair to form an oscillator, and an inductor as a "storage coil". Much like the Satcure circuit, but capable of more power output.

Of course, I haven't looked at it in a while and my memory may be way off. I'll edit this if that's the case.

Gadget, the beauty of it is that there is no inductor coil that I can see. Takes 6 components apart from the LED to build it. 2 transistors, 3 resistors and 1 capacitor. But I'm sure you're right about the pulsing. That's why the voltmeter only measures 2.6V.

I like the circuit because I think it is possible to make it more robust by changing the components to those that accept higher currents. I'm guessing that the pulsed voltages would remain the same. Someone managed to run an LS on it for a few seconds before it started getting hot and I believe that it would work once the components are substituted. I'm also guessing that the pulsing performs a regulation function as well, so that the LED does not dim out the same way it would if it were directly connected to batteries. ie, the brightness would be fairly constant until the batteries gave out.

BTW, one of the other phenomena I've managed to observe with this circuit is that if you accidently short the LED terminals while the power is plugged in, the circuit starts to overheat, especially that green resistor, and the LED just barely glows.

And yes, it can run 3 LEDs as brightly as the Matrix can, so this might be a suitable circuit to implement in the conversion I mentioned in my other thread.

Gadget, the beauty of it is that there is no inductor coil that I can see....

....the circuit starts to overheat, especially that green resistor

I think you just found your Inductor. I`m fairly sure that the big green resistor-looking thing is actually a small inductor. It just looks like a resistor. The coils are wound round a cylindrical ferrite core and encapsulated in the same stuff resistors are encapsulated in. I don`t know offhand how to decipher the stripes though (it may be the same colour code as resistors use- but what value does it refer to? Henries? Millihenries? etc...), I`d have to look up a component catalogue or 2 and see if it`s in there.

The sure way to tell is if you have a meter that will measure inductance. They are not too common though. Another way that won`t give you the value directly but will confirm it is an inductor, is measure its resistance connected in series in a DC circuit (plain old ohm-meter)- it should be really low. Then measure it in series in an AC circuit- measure volt drop across it and current flow through and use V/I=R. The resistance on the AC supply should be much higher.
Where to get safe AC? Well some wall-wart transformers give AC output, (check the rating sticker on the front), those cheap low voltage halogen-bulb desk lamps are normally 12v AC (but watch out for electronic transformers- they don`t work without a decent load on them), or if you`re really careful you can take apart a DC power supply transformer and find low voltage AC on its secondary side. Watch out for those live 120 volt terminals though!

I would like to take my Brinkman and remove the front lens. Just how did you get yours apart. Inside it looks like it is glued. It is possible to open it up without destroying the plastic?

Thanks.

Gadget posted a way to do it with paper clips. I could not get it to work.... so I used dykes and pliers and RIPPED...

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Chris M.:
Gadget, the beauty of it is that there is no inductor coil that I can see....

....the circuit starts to overheat, especially that green resistor

I think you just found your Inductor. I`m fairly sure that the big green resistor-looking thing is actually a small inductor. It just looks like a resistor.....
<HR></BLOCKQUOTE>

Yep, Chris nailed it. The green thing is an inductor, not a resistor. ;-)

Harrkev, here's the instuctions I wrote for disassembling the Brinkmann.

How to take a Brinkmann apart

If the first link is dead, try this one...
Another copy of the same instructions

Be patient, it usually works.

Gadget - Thanks for the Brinkman dissassembly instructions. I tried a while back based on some text from this forum, but couldn't get the thing apart. Hopefully your instructions and pics will do the trick.

Also, that video on your site with the dirt buggy doing a forward flip is GREAT!. What a rush.

Hehe! Lucky for me, I was taping, NOT driving!

We (SAE student club) built that from a pile of chom-moly tubing, a 10hp Briggs & Stratton, and some duct tape.

Good luck with the Brinkmann.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Steelwolf:
.... I can't seem to find anything about the transistors they used. It doesn't appear in any of my regular catalogs. ....<HR></BLOCKQUOTE>

I think I have a cross ref. for you.

NTE289A (NPN) & NTE290A (PNP)
Silicon Complementary Transistors
Audio Power Amplifier

I searched for "8050" and "9015" on NTE's website cross-reference engine. http://www.nteinc.com/

Being as you are "down under", you may still have to find another substitute, but I think they are pretty common transistors.

Thanks to all for your help, esp. Gadget for that link. I knew it was a notion too good to last.

Are we sure that the green thing is an inductor? Admittedly the resistance is very low, something about 2ohms. But neither is there a lot of voltage across it when it is running.

Now... if I could only find one of those inductance meters... and a capacitance meter as well.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>I'm also guessing that the pulsing performs a regulation function as well, so that the LED does not dim out the same way it would if it were directly connected to batteries. ie, the brightness would be fairly constant until the batteries gave out.
<HR></BLOCKQUOTE>
Does anyone have a confirmation for this? Does the LL stay at constant brightness as the batteries wear down?

I've just made a few more measurements. IF the green thing is indeed an inductor coil, then it would probably be 100uH. I have a whole bunch of commercially made chokes and the one that came closest was the 82uH choke at about 1.1R whereas the green thing was about 1.6R measured on a DC multimeter.

Of course I don't discount the notion that I have completely missed the theory behind all this and misintepreted the measurements.

More coming... watch this space.
BTW, how come no one else has posted details about this circuit yet? How does it work? Why does it work? Is it a basic oscillator circuit with coil and a smoothing capacitor? Someone once managed to draw 300mA when hooked up to the LS LED module but overheated the transistors. Can the transistors be substituted for another which is more able to withstand the higher currents?

I took apart both. Brinkman and Skylite
The one from Riegel systems is a lot easier to draw out. They both look REAL similar.
I could never get one to work that I BUILT. I used smt coils from Coilcraft and that may have been the problem. It was about the time the LS was announced and I sort of dropped everything.
Skylite

Here is something that appears to tell inductance value if a "Tubular Encapsulated RF Choke" is an inductor

hope it helps

Nick: Thanks for that link.

According to that chart, it would seem that I am right. It is a 100uH inductor. Danggit. Ah well, not so difficult to find.

Another thing that occured to me to test was the regulation of the output. I put it in to my lab power supply (Dang I love that thing! One of my more useful purchases, I think) and fed the circuit with a combination of volts and current to simulate the standard battery supply.

As I varied the power supply to simulate the batteries dying, the light output dimmed as well. This was very disappointing! I varied the voltage first, feeding as much current as it wanted, then I kept the voltage constant and reduced the current. In both cases, the LED dimmed in proportion to the "battery drainage".

As an aside, the PT Matrix didn't change in brightness until the batteries were almost dead.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Steelwolf:
I've just made a few more measurements. IF the green thing is indeed an inductor coil, then it would probably be 100uH. I have a whole bunch of commercially made chokes and the one that came closest was the 82uH choke at about 1.1R whereas the green thing was about 1.6R measured on a DC multimeter.

Of course I don't discount the notion that I have completely missed the theory behind all this and misintepreted the measurements.

More coming... watch this space.

BTW, how come no one else has posted details about this circuit yet? How does it work? Why does it work? Is it a basic oscillator circuit with coil and a smoothing capacitor? Someone once managed to draw 300mA when hooked up to the LS LED module but overheated the transistors. Can the transistors be substituted for another which is more able to withstand the higher currents?<HR></BLOCKQUOTE>
If you could post the schematic you reverse engineered from the flashlight I could try and help out. I'm an EE (Electrical Engineer) and I can probably tell what makes the circuit tick. But since I don't have the flashlight in question, I'll need someone else to reverse the schematic for me.

I've been lurking here for couple of weeks. I too am searching for the "ideal" power supply for driving LEDs. I see that many others here are also tinkering with these interesting power supply circuits.

And yes, that "green resistor" is really an inductor. Also, using a ohm meter to measure the DC resistance of an inductor to try and figure out its inductance is useless. You need to either use an LCR meter (or an LC meter) or simply read the color code - if it has one.

Marlan: Thanks for your offer. I will try and draw it out and send it to you. I think there is some use in measuring the resistance of the inductor and comparing it to other inductors. It isn't perfect, but it does give an indication.

So far, I think the ideal circuit is the one being made by Gransee. The Arc-AAA is really very good. Not only does it boost the voltage and drive the LED as bright as it would go, but it does so on an even level until the batteries give out... and then still drive the LED at a lower light level.

I'm not sure, but I think the couple of circuits I have been trying, the Brinkmann LL one included, doesn't do it like the Arc-AAA. They appear to reduce the light output as the batteries give out. Got to try and figure out how he does it.

At one time, Granseer was thinking of making that available to any of us. The LS thing got in the way I believe. I THINK I remember him saying he would epoxy it to protect his circuit and offer it as a module. No price was ever mentioned that I can remember. I am sure it would be fair however.

What I have been doing is watching Wallmart and buying them up when they reduce them to 8 bucks on sale. Unfortunately they have quit doing that. I then tear the guts out and use the module in whatever I am currently making.

How many LEDs can be comfortably driven by the Brinkman circuit? Over the weekend I converted one of the Rayovac swivel-head 2AA lights with the Brinkman LL board and 3 LEDs (I need more practice soldering- it is way ugly inside!)