UKE 2AAA led current regulatet ?

Illuminated

Enlightened
Joined
Oct 26, 2002
Messages
886
Location
Tipp City, Ohio
I think it qualifies as "semi-regulated". Down to 50% output after 19-20 hours, if memory serves. I think it was Quickbeam that did a nice review on it.

I have one, and I like it for the price.

John
 

Doug Owen

Flashlight Enthusiast
Joined
Jan 30, 2003
Messages
1,992
UKE 2AAA LED performance

I ran some voltage, current and light output tests for mine that might prove 'enlightening' (sorry, couldn't resist):

,8 Volts, 3 mA, 3 cp
.9 7.7 11
1.0 10 21
1.1 12 31
1.2 15 42
1.3 17 53
1.4 20 65
1.5 23 79
1.6 26 100
1.7 30 117
1.8 32 131
1.9 34 156
2.0 37 167
2.1 40 185
2.2 45 220
2.3 51 256
2.4 57 280
2.5 63 326
2.6 70 364
2.7 77 386
2.8 84 419
2.9 93 457
3.0 104 475
3.1 107 519
3.2 115 534
3.3 124 572
3.4 135 585
3.5 146 597
3.6 157 603

Several things seem clear, at least to me. Yes, there is electronics in there, no, it's not regulated (as it's normally defined) and under the 'time to half original birghtness' test 19 or 20 hours seems highly unlikely.

Let's assume 3.0 Volts to start, 100 mA more or less, 475 cp as I measured it. Half level is at 2.2 Volts, 45 mA. Let's assume an average current of say 75 mA from the two AAA cells. Average voltage is 1.3 Volts times .075 Amps is 100 mW load per cell. Using the Energizer E92 curve for 100 mW looks like a bit under 400 minutes to 1.1 Volts, under 7 hours, more like a third that time.

Doug Owen
 

Quickbeam

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Jun 19, 2001
Messages
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FlashlightReviews.com
Re: UKE 2AAA LED performance

I think it qualifies as a voltage boost or "step up" circuit which provides what is considered a "semi-regulated" discharge profile. AKA it drains the batteries better and faster than direct drive, but still has a sloping discharge curve.
 
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