My SL-20x is now digital...

[dano]

Well, I bought a Digital tail cap for my Streamlight SL-20X, and it's a pretty cool gadget, that offers a flash mode, and adjustable beam intensity...

They run about 25-30 bucks, but a few usually show up on Ebay for 10-15 bucks. Overall, it's a good improvement, especially if you use the 35X bulb in the 20X...

--dan

 

[Brock]

So does it yellow as it dims? I have stayed away from dimming small halogen lamps because I have been told running a halogen lamp at reduced levels causes the lamp to fail sooner. I wonder how much this really effects lamp life?

In any case they look really neat.

 

[dano]

Yup, it yellows as it dims...As for lamp life, it's a big unknown, so far...

--dan

 

[TripleDouble]

Does anyone know how it dims? With a resistor or drop down voltage regulator? Efficiency?

Would it be possible to fit one of those things into a maglite, or are the threads different?

 

[lemlux]

What happens if a halogen is pulsed?

 

[dano]

The electronics are built into the tailcap, and appear to consist of a small circut board and a few IC's...

I don't think it'll screw onto a Mag...

--dan

 

[duffahtolla]

My guess is that pulsing a halogen would kill it quicker.

When at full voltage, the filament evaporates and condences on the glass walls. The halogen reacts with the deposited tungsten and frees it from the wall. This new chemical meanders all around until it hits the fillament where the chemical breaksdown and re-releases the halogen and deposits the tungsten back onto the fillament.

At proper voltage alls okay. At reduced voltage the walls are too cold to allow the reaction between the tungsten and the halogen to occur so you get 'black' glass.

The site listed bellow says that dimming isn't really bad in practice because the lower voltage also means lower temperature and hence less evaporation from the fillamment.

Pulsing would give you the worst combination possible. High fillament temperatures (at times) and walls not hot enough to recycle the tungsten (ever).

Read all the gory details here

 

[Saaby]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by duffahtolla:
My guess is that pulsing a halogen would kill it quicker...

The site listed bellow says that dimming isn't really bad in practice because the lower voltage also means lower temperature and hence less evaporation from the fillamment.

[Snip]

Pulsing would give you the worst combination possible. High fillament temperatures (at times) and walls not hot enough to recycle the tungsten (ever).

Read all the gory details here<HR></BLOCKQUOTE>

Correctimondo. Pulsing would kill it faster than...well something really fast. Among other things the filliment would, depending on how fast you were pulsing it, go from hot to cold to hot to cold to hot to....you get the picture.

If you pulsed it extremly quickly you would think that there wouldn't be much difference between the hottest and coldest filiment temps. But something that delecate expanding and contracting that fast is bound to die soon.

Slower pulsing is probably even worse! Sure it isn't expanding and contracting as much but there is even more of a temperature swing between hot and cold.