> On Nov 17, 2022, at 1:48 PM, gregebert <[email protected] > <mailto:[email protected]>> wrote: > > Constant-current is an excellent approach for incandescent devices because it > eliminates the inrush current-surge that shortens the life of the filament. > Recall that a cold filament has lower resistance versus when hot; > current-limiting also allows the filament to heat-up slower, which reduces > mechanical shock.
PTC thermistor. I didn't understand this simple principle for a long time. > I always hated it when I walked into a dark room, flipped-on the light > switch, and POOF went the light bulb. One of my other hobbies is old Christmas lights. The inrush current is a huge deal because most of what I have is rated 15V and wired with 8 bulbs in series. You can't mix different bulbs together unless you use a dimmer or better yet a variac to slowly ramp the voltage up because the curves are different. The bulb with the lowest resistance will always heat up more rapidly and will be the first to blow. What's needed are miniature base festoons with the sockets in parallel. These are pretty rare as the only thing wired this way were some sets with 6~8V blinker bulbs and a transformer that were only made for a short time in the mid-'50s. I managed to get three of them with 20 sockets apiece back when they were only $25 on eBay. I use variacs and 12V transformers intended for low voltage outdoor lighting. Most of them will bubble reliably at 12V which derates them 20%, further increasing lifetime. Bonus feature: if a bulb blows all the others stay lit. And despite my best efforts it still happens occasionally but then the bulbs may have many hours on them. Just as many here were stocking up on Nixies decades ago, I was chasing Christmas lights on eBay, especially bubble lights. I was that noob guy who outbid everyone by going fifty cents over the average price per unit. Today they can't be had for three times what I paid in 2007. Stupid noob, huh? I've never taken an exact count but I have well over 100 bubble lights in my collection. At least a dozen are purple, the rarest color. They're not for sale. Terry Bowman, KA4HJH "The Mac Doctor" https://www.astarcloseup.com "If only you could see what I've seen with your eyes."—Roy Batty, Blade Runner -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/AC652093-8E1A-4B1A-86BF-CADB52027F6D%40gmail.com.
