On Tue, 11 Jun 2002, M. Adam Davis wrote:

>Another idea is to take advantage of fixtures that have more than one
>bulb.  A pic and a few SCRs (or replace the pic with some discrete
>components) in the fiture.  It turns the bulbs on in series, let's then
>warm up for half a second, then switches them to parallel.

And the weakest in the chain will fail first thereafter having all the
bulbs switched on 'dead cold' when paralleling.

Cheap cheap cheap places that run lots of bulbs use thermistors in each
bulb. Less cheap places can afford controlled turn-on dimmers. They use
this to save manpower, not to save bulbs. It costs more to keep spare
bulbs and janitors than to lose power on thermistors.

And Roman, thermistors are much more reliable than anything that has more
than two pins and contains a dumb blob of metal and semiconductor oxides
sintered in a press. Do not confuse these with the PTCs in TVs. They do
not come from the same mother.

Peter

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