question for the engineer types out here

LEDBE
C

chilli

Newly Enlightened
Joined
Dec 14, 2003
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11
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GA
with the circuit displayed on the following page how many batteries of what type would be possible in say a solitaire or a mini mag? looks like a fairly strait forward circuit for the diy entry level modder. and i am definately entry level.
thanx in advance for any assistance offered.
http://www.emanator.demon.co.uk/bigclive/joule.htm
 
That circuit should work ok on one AAA, but if you want an AAA powered LED light you should just buy an Arc AAA. It's about the same size as a Solitaire, but a zillion times better. It's a favorite around here. See http://www.arcflashlight.com for more info.
 
Looks like a fun little circuit. The purpose of it is to allow a LED to be powered with one 1.5 volt battery. So, yes it would work in a solitaire or similar one cell light. A mini mag would be overkill for this circuit, with 2 AA batteries you can power a 1 watt LS LED with the right circuit. Some of the drop in pills listed in the home made and modified forum are much better ideas for mini mags.

Yes, you could buy a Arc AAA or for a bit less you could pick up a Dorcy AAA at Wal Mart, but building it yourself has its own rewards.
 
You can check out the modder's reference database thread at the top of home made/modified lights forum. I have a link with detailed description of how to build a SatCure (aka. Joule Thief) plug for Solitaire in there.
 
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what would happen if i put two aa batteries in this circuit?

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You will most likely blow the LED. IIRC, that circuit exhibits a dumb boost behaviour. There was a guy who added an extra transistor and resistor to allow a little throttling back so that the circuit exhibits a regulating behaviour. I built that second circuit and found that it will work quite happily with 2 AA though the schematic shows a 1.5V input.

The circuit has the second resistor inbetween the LED and ground. The base of the second transistor goes inbetween the LED and the second resistor. Collector goes to base of first transistor, Emitter goes to ground. I'll see if I can find the schematic online.

Remember YMMV. This circuit is highly dependant on the type of transistors you use, the type of core, number of turns in the primary and flyback coils, and even the size of core. I was able increase the output power a fair bit by just changing to a larger core. I've found some transistors that should perform better than the generic 2N2222A and I'm going to swap them in as soon as I have the time.
 
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