357 Operated LED?

[rdoty]

Can a LED be operated directly from a 357 (CR44?) battery and if so what type? The 357 battery is rated 1.55V but most LED's are rated 1.9V min plus the current seems too high.

 

[birdman0_o]

No it will not work on a single battery, an LED needs a 1.9V voltage drop. You can put two batteries in series though with an appropriate resistor

 

[rdoty]

Thanks,
That's what I thought but I remember a very small item that my daughter had, about 1/2 in dia x 1/2 long, that had a 357 battery in it and a very bright LED. I've since lost or misplaced it so I can't tear it apart. Any thoughts?

 

[nz_electric_specialists]

dunno, but the simplist LED cicuit you can make is just plugging the LED into the wall, yes it will shoot the top off at a high speed but for a miniscule of a second the LED will be pretty bright even though ya wont see it. ][_,([])][_, ^_^

birdman0_o's idea sounds probably about the best you could do

 

[rdoty]

since the LED is a semi-conductor I'm wondering if there isn't some relationship between how high the top goes (and how bright that flash is) relative to which part of the cycle creates the breakdown. Wanna check that out for me NZ?

BTW I did come across some LED devices rated as low as 0.5V but they seem pretty rare.

 

[OutToLunch]

you can light up an led by placing it directly across those watch batteries no problem - done it a number of times. easy to try out too - its just 2 components!

 

[Externet]

Yes, the correct led can turn on from a single 1.5V cell. Many keychain lights are that. A 'coin' cell direct to a red led.

Just try !

 

[Hero999]

No, a red LED requires two 1.5V cells.

A single cell will work but it has to be a lithium (3.3V) cell.

Another option is to use a boost converter such as the Joule Thief which can power an LED from a single cell.