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whit3rd whit3rd is offline
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Default bike headlamp LED, 4.5V (AA), resistor in series needed?

On Sunday, April 15, 2018 at 9:30:31 PM UTC-7, Mike S wrote:
On 4/15/2018 8:30 PM, mike wrote:


I was thinking of building a simple voltage/current regulator, and
wondering how much current would be spent in the ct.


Yeah, for battery powered gizmos, that's important.
The easy solution is a funny chip that has a builtin
current regulator, and has (as well as current limit) thermal
protection (when mounted thermally to the LED parts).

Look on eBay for AMC7135 (about 1W delivered to an LED, use two or
three in parallel for higher power lamps).. This is a good solution
for a 4.2V battery input, which a power-wasting resistor can never
improve on. Alas, battery and LED options must be driven by the
choice of such a chip.