On Sun, 24 Jul 2011 15:39:54 -0600 "adastra" wrote: > I love this idea! Unfortunately I can't find any reference to commercial= ly > available 3' long tubes that work this way. There are some regular bulb > shapes, but I'd need a really lot of those. Far from expert, but last week three of the dual-tube boxes at my wife's pharmacy broke down - mainly brittle sockets (as mentioned in the list earlier). So I decided to replace the old heavy ballasts + starters with electronic ones. I was quite surprised that the ballasts I found shorted out all filaments except one (remember, 2 tubes/box). I understand this filament was just used to detect the presence of a tube in that pair of sockets. So: 1) instant switch-on of both tubes 2) no warm-up at all of the filaments 3) (I suspect) no problems with lifetime, as filaments are not heated. I was so happy, I tried one (old) tube which had both filaments burned. That didn't work though ;) I suspect the high frequency of the electronic ballast does need enough surface area to start the ionisation. BTW, there is no such thing as 'an' electronic ballast - models abound, and some do actually connect all filaments. Greetings, John --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .