Joule Thief

MarkE · January 27, 2015, 12:44:17 AM

Quote from: Pirate88179 on January 26, 2015, 10:04:50 PM
No resistors or anything else in these bulbs. The amp draw was tested from an AA battery, but I use a D cell in my reading light so it lasts longer. So far, I have not had to change it. I don't know how the chips in the LOA bulbs are wired...probably series but I can not confirm that. No scope shots of the circuit as I was told several years ago that the high voltage could damage my Tektronix 2213. I am not good with my scope so I played it safe.

TK has one of these circuits that I sent him, we could ask him if this can be safely scoped. All I know is that I bought about 8 of these lamps 4-5 years ago and all of them are still working great. I also made lights for my daughter, and some of my friends and all is still well with them too.

Bill

PS I see that this is an old photo I had on file. All of my bulbs have a standard Edison base, but this gives you an idea of what they look like.

TK has a 100X probe. He can safely look at this circuit.

TinselKoala · January 27, 2015, 04:19:07 AM

Is it the modified flash camera circuit? Yes, I installed that one in a jar with a gutted CFL tube, it works quite well with that. I call it the "Pirate Light". I'll dig it out and scope it, probably have to wait till tomorrow though. I'm bushed from working on something else. Unfortunately I don't have an equivalent LED bulb to try it on.

I have a failed Cree LED bulb that I haven't taken apart yet to see why it failed. Only got 30 or so hours out of that one, a 18 Watt 1600 Lumens unit that I was running in the overhead fixture on the normal mains supply. I liked the bright light from it, but it sure didn't last very long. I actually don't know how to take it apart without messing it up, anyone have any ideas?

synchro1 · January 27, 2015, 04:57:02 PM

Quote from: MarkE on January 27, 2015, 12:43:31 AM
It doesn't work that way. The I²R losses per bulb go down dramatically when adding bulbs, but then the number of bulbs wasting energy in their individual I²R goes up. Unless one starts at a point where they are kicking the snot out of LED to begin with, the efficiency gains had by paralleling more LEDs quickly hit diminishing returns.

@MarkE,

Yor're just shooting it out your ass. A few comments back you were confused into imagining we were taking about 3V LEDS; Now you pretend you know more then me after months of testing and half a dozen videos. You grow despised as an ignorant "Know it All". Wise up to yourself Bub!

Pirate88179 · January 27, 2015, 07:38:42 PM

Quote from: synchro1 on January 26, 2015, 11:33:31 PM
@Pirate88179,

That's beautiful. I broke one of those bulbs and examined the circuit at the base. There're several standard componants, capaciitors inductors etc. I'm sure it rectifies to DC. My tests confirmed that additional bulbs generate light more efficiently. Adding two additional bulbs would probably deliver the same amount of light for 100 ma instead of 150 based on a savings factor of 17% per additional bulb.

We must be talking about different bulbs. I have not purchased any of them in a few years, so maybe they have changed but, I completely took apart my first one as I assumed there was some circuitry in there...nope. Just two wires connecting the leds to the Edison base. No resistor, nothing. That is why I was suggesting folks to use them back then as no mods were needed.

Bill

Pirate88179 · January 27, 2015, 07:46:12 PM

Quote from: TinselKoala on January 27, 2015, 04:19:07 AM
Is it the modified flash camera circuit? Yes, I installed that one in a jar with a gutted CFL tube, it works quite well with that. I call it the "Pirate Light". I'll dig it out and scope it, probably have to wait till tomorrow though. I'm bushed from working on something else. Unfortunately I don't have an equivalent LED bulb to try it on.

I have a failed Cree LED bulb that I haven't taken apart yet to see why it failed. Only got 30 or so hours out of that one, a 18 Watt 1600 Lumens unit that I was running in the overhead fixture on the normal mains supply. I liked the bright light from it, but it sure didn't last very long. I actually don't know how to take it apart without messing it up, anyone have any ideas?

Yes, the flash camera circuit...scoping that would be great. (Try not to get zapped again, ha ha.)

Is your cree anything like the 800 lumen 60 watt equiv. that you have seen me use in some videos? Glass globe, heat sink ring and plastic base going down to the base?

If it is, I can tell you how to do this easily. (Well, it was easy for me after I broke the plastic and saw what was inside)

Here are some photos to see if they are made similar.

Bill