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Low voltage white LEDs.

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Ian Field
Guest

Thu May 11, 2017 9:20 pm   



First bicycle headlamps and now an under shelf light.

I'm starting to find white LEDs that run from 2x AAA cells - can't find any
boost circuit at all.

Anyone got a link to a data sheet that explains this?

Thanks.

Jon Elson
Guest

Sat May 20, 2017 4:18 am   



Ian Field wrote:

Quote:
First bicycle headlamps and now an under shelf light.

I'm starting to find white LEDs that run from 2x AAA cells - can't find
any boost circuit at all.

Anyone got a link to a data sheet that explains this?

Thanks.

The latest white LEDs seem to drop about 2.6 V or so at lower current. So,
just get some big LEDs and run them at reduced current, and they should run
off 3 V from Alkaline cells. Likely they would be real dim and fade quickly
on NiMh cells.

Jon

Ian Field
Guest

Sat May 20, 2017 9:48 pm   



"Jon Elson" <elson_at_pico-systems.com> wrote in message
news:FqKdnaaPjrkSOoLEnZ2dnUU7-aOdnZ2d_at_giganews.com...
Quote:
Ian Field wrote:

First bicycle headlamps and now an under shelf light.

I'm starting to find white LEDs that run from 2x AAA cells - can't find
any boost circuit at all.

Anyone got a link to a data sheet that explains this?

Thanks.
The latest white LEDs seem to drop about 2.6 V or so at lower current.
So,
just get some big LEDs and run them at reduced current, and they should
run
off 3 V from Alkaline cells. Likely they would be real dim and fade
quickly
on NiMh cells.


Trying that would probably tell me something I didn't know.

There's a shelf light laying about on my desk - so far I just couldn't be
bothered charging a couple of AAA cells to try.

Jon Elson
Guest

Sun May 21, 2017 1:58 am   



Ian Field wrote:


Quote:
Trying that would probably tell me something I didn't know.

There's a shelf light laying about on my desk - so far I just couldn't be
bothered charging a couple of AAA cells to try.

I built a few fluorescent retrofits with strings of 20 1 Watt LEDs, so I had
to know a bit about the LED characteristics to do it right.

Jon

Ian Field
Guest

Sun May 21, 2017 11:25 pm   



"Jon Elson" <elson_at_pico-systems.com> wrote in message
news:v5OdnQQrouOIRb3EnZ2dnUU7-X2dnZ2d_at_giganews.com...
Quote:
Ian Field wrote:


Trying that would probably tell me something I didn't know.

There's a shelf light laying about on my desk - so far I just couldn't be
bothered charging a couple of AAA cells to try.
I built a few fluorescent retrofits with strings of 20 1 Watt LEDs, so I
had
to know a bit about the LED characteristics to do it right.


The ones I have just turned up on the market - I was curious how they got
away with running them off 2 cells and no boost circuit.

elektroda.net NewsGroups Forum Index - Electronics Components - Low voltage white LEDs.

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