staged dimming

[WyrreJ]

PWM requires a much more complicated circuit. If you want to run at peak efficiency than PWM may be the way to go, but not always. But in applications like this, there is hardly any need for it - reduced efficiency for a few seconds isn't going to hurt anyone. Which is all really beyond the point, as an engineer I'm sure you can appreciate my desire for precision -- "LEDs don't dim" is just simply incorrect.

[tom4bren]

PWM is definitely too complicated for this application.

LEDs can dim - a little. If you want to retain the dimming though, keep the incandescant setup (I meant to make that statement in my earlier comment but forgot). If you try to dim LEDs (especially in an array like ETL is using) you'll end up frying it or the circuit. LEDs try to be constant power so the current will increase dramatically as the voltage drops ... and the LEDs are NOT protected by the fuse.

The more pertinent question is: can ETL debounce his relay so that it doesn't buzz?

[Lizardmen3477]

Wow where did u get that and how hard is it to install i would love to buy that please send me website and how it was to install. Thanks Lot.

[WyrreJ]

LEDs can dim - a little.

No, they can dim a lot.

Here is just one of many graphs of the output of an (unregulated) LED flashlight brightness versus time starting with a fresh set of batteries:



They pretty much all look like that - 50-75% dimming.

Here's a ton of discussion on PWM versus current-control for LED lighting.
The general consensus seems to be that current-control is preferred.
http://www.candlepowerforums.com/vb/...d.php?t=152185