Re: Putting Red LED's In Osram Dot it light

On Feb 22, 1:52 am, Ecnerwal <LawrenceSM...@xxxxxxxxxxxxxxxxxxxx>
wrote:
. +--[JUMPER]--+--[LED>]--[R]--+
. | | |
. | +--[LED>]--[R]--+
. [SWITCH] | |
. | +--[LED>]--[R]--+
. | |
. +--------[+BATTERY]----------+
Maybe just getting a cheap
flashlight and installing one red LED in that. What resistor value
would I need if this flashlight runs on two AA or AAA batteries? I
think I measured about 40 mA on one LED before they all went out.
Might have been the one that burnt out.

At an earlier point, I believe you had the reasonable response that
you'd perhaps just build the thing on perfboard from scratch, following
the correct circuit (the one I left above) rather than the flawed one of
the original light. You then appear not to have done that, but that
makes a great deal of sense, as you might now realize, having tried and
fried with the original.

Yes that's right. Much easier to install in an old flashlight lamp
base.

2AA or AAA are 3V.

Typical red LED is 2V nominal. 20mA is typical safe current for generic
LEDs. So you have 20mA and one volt = 50 ohms. 51 is close enough, 63
would give more margin of safety, but somewhat less light.


Thanks, I still have the 56 ohm resistor I used when I fried the LED.
If it tests good I'll use that. I also have the two other red LED's
which work, so obviously, I'll be using one of them. Thanks for all
your help. Greatly appreciated!
.

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