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Driver Compilation Thread - All Drivers In Just One Thread!

Toke

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My hope is that a diode and capacitors will straiten it out enough for a LM317 to regulate the current reliably.
 



millirad

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^ Yes, I hope so. +1 for giving it a try. It would be another interesting design posted here if it works. You prefer AA/AAA alkaline instead of using lithium ion rechargeable batteries, because your host requires them for their size?

New update on my labby. It is running at ~1350mw, and is very bright. I put a 25 ohm 50 watt in parallel to one of my 3 ohm 50 watt resistors, to reduce the dropping voltage, for the load. That was not nearly enough, so I added an 8 ohm 20 watt in parallel with the other 3 ohm 50 watt voltage dropping resistor. This finally allowed my "crazy" 7 x ddl driver circuit to achieve the power I wanted to run the 445 at. The lm317's are slightly warm, and the 3 ohm dropping resistors are a bit hot after 5 minutes, so even though they are rated for 50 watts, I will heat sink them. 1350mw is a slightly risky power level, but possibly will achieve some longevity for the LD. I'm going to create a simple tunnel effect with a "dental" first surface mirror and a Radio Shack motor, with the mirror at ~92 degrees. I'll post a pic once I have done it. ;-)
 
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Toke

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You prefer AA/AAA alkaline instead of using lithium ion rechargeable batteries, because your host requires them for their size?
Yes, that is one reason, another is that I have them, the 3. is more irrational.
I want to see if I can do it. :D
The drivers will also have to fit into pipes/extension sleves of 9 and 12 mm diameter.

Those effect resistors in your picture are designed to operate at too hot to touch. I have seen them used as heating elements in small switchboards.
Adding the two larger resistors have changed your resistance from 6 Ohm to 4,88 Ohm. That is borderline voltagedrop for running the LM317´s, have you tried just one 3 Ohm resistor?
 

millirad

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I have been trying different configurations, and I'm at the maximum voltage, that I want to drive my lm317's to keep them cooler. The ~1350mw power on the 445 is where I prefer to stay, so I probably wouldn't go with just one 3 ohm dropping resistor. Yes, both of the 3 ohm resistors will get heat sinks, because they get hot after about 5 minutes.
 

Toke

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I am doing a quick and dirty driver for testing and have found a solution for the 12V wall-wart to red diode problem.
This LM317 can easily pull 500mA without heating up. :D
(Heatsink is from a broken UPS)

ETA: A MOSFET can apparently not be used as the transistor in a joule-thief. :( Will have to go shopping tomorrow.

ETA: I am up to 3V on the joule thief, will get cobber wire and ferrite beads sometime next week.
That will likely improve matters.
(A capacitor across the output after the diode really helps.)
 
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Benm

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I dont think the joule thief circuit will provide a usable amount of power, and if it does, it will vary greatly with battery condition (internal resistance). Perhaps you could power a 5 mW red from it, but not something that consumes in the order of half watt or more.
 

Toke

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I dont think the joule thief circuit will provide a usable amount of power, and if it does, it will vary greatly with battery condition (internal resistance). Perhaps you could power a 5 mW red from it, but not something that consumes in the order of half watt or more.
I have more or less come to the same conclusion. It just looked so promising.:(
 

Vaporizer

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Original deleted.

I was missing the single cell feature.....duh.
What if the toroid was wound 2:1 doubling its "ringback"?
 
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