First I apologise if I am repeating what has already been covered by this
thread

Jinx wrote

> A couple of months ago I had a big b*tch about my spotlights
> regularly blowing. I've done some testing with series resistors.
> Very happy with the results
>
> http://home.clear.net.nz/pages/joecolquitt/0bulblife.html
>
I've been looking for graphs like that for some time now, particularly with
regards to low voltage halogen lamps. Do you have any reference you can
point me to ? I know I have the information somewhere but I cannot find it
and all references on the web result in broken links.

If it is the switch on surge that is the predominant failure mechanism, then
instead of a resistor have you considered using a NTC (Negative Temperature
Coefficient) Thermistor. Some (considerable) time ago these used to be
marketed, for insertion in the bottom of an ES type lampholder before you
screwed in the lamp bulb.

The following deals with the subject of using NTC Thermistors for In-Rush
Current Limiting
http://www.epcos.com/inf/50/ap/ntc.pdf

Regards

Chris

--
http://www.piclist.com hint: The list server can filter out subtopics
(like ads or off topics) for you. See http://www.piclist.com/#topics