Dorcy 1AAA ??

Can I use a rechargeable NiMh in the Dorcy ? If so, will it have an effect on the output ?

Yes. No effects that are really noticable. Possibly a shorter run time.

Actually you might get a longer run time, but dimmer output from the 1.2v NiMh cell vs alkaline. The alkaline will seem bright for the first few mins before it drops down to a level below the NiMh cell.

I use nothing but NiMh cells in my 1AAA Dorcy lights without any problem.

Me too, only NiMH's. A fresh alky is a bit brighter, but soon becomes less bright than the NiMH. Then it will run like forever at an ever dimmer level, but never so dim that you can't see your way in the dark. It finally reaches a stage where it will light and run a long time, but won't re-light without resting a while. The NiMH is nearly as bright as it gets, but with almost no dimming until it dies, which is much more rapid, but not so fast as to strand you in the dark. I always charge a NiMH WAY before it is fully depleted, only once did I wait for major dimming in my Dorcy, just to get a feel for how much use it took to do (it's a lot).

Oh yeah, almost forgot, put a Nichia CS or other high quality LED in there and it will be much brighter on a NiMH than the stock one is on a fresh alky or even lithium. Nicer beam, too.

Hondo