Barry, As I remember it - the deviation of the shape of the current (as seen on the scope) from normal sinusoidal 'curve' was readily apparent when a diode was placed in series with a bulb. The one thing I didn't do (and now wish I had done) was calculate the "spot" or instantaneous R the bulb presented at critical points such as at the peak of the applied voltage sinusoid, the 10% applied voltage point before and after the zero cross over point, etc. I should repeat the same lamp experiments today with a digi-scope - and this time record the waveform for further analysis such as computing the "dynamic resistance" of the filament as it changes over a complete cycle. This same experiment should also be performed for a new series-of- cycles (as if I had turned the lamp on for the first time that day) starting at a zero crossover point. The experiment should furthermore be performed on several bulbs from different lots from the same manufacturer, then other tests involving other manufacturers as well ... then come the 'tests over life' on each bulb whose original performance characteristics were recorded in their infancy ... Did I mention that I should also measure light-output and record for future analysis? That would go without saying I guess. Alas, years ago, when I first looked at this problem all I had to work with was a an old bi-stable Tek storage scope of the 564 series - and that lacked data-record capability save the 'usual' Polaroid camera that slipped over the CRT bezel ... The SS/LED lamps should be on the market at competitive prices before I *ever* get a chance to go that far, however!! Jim PS. I'm a big user of the SS flourescent (sp?) lamps as others here have also indicated, save for about 3 or 4 incadescent lamps where they are under the control of X10 modules - or the garage/ external lighting where the flourescents (sp?) 'come-up' slowly when the ambient is cold. ----- Original Message ----- From: "Barry Gershenfeld" To: Sent: Tuesday, July 03, 2001 8:33 PM Subject: Re: [EE]: Bulb Life, X-10 turn-on would seem to up life >Why is the section of my original message missing that >describes that I observed a *significant* change in the >current waveform between full cycles of 60 Hz line being >appled to a lamp versus what I obeserved when using a >diode in series with the same lamp? Well, I actually did miss the point, as you suggested, and for several reasons. One is the way I handle messages. I don't always pay 100% attention, since there are so many messages to read. Another is that I generally read all the messages in a thread before I write a reply. In this case I knew that somewhere, someone had done some actual measurements but I didn't remember who. And in my haste to trim the quoted part I didn't notice that it was you. On the other hand, what you reported was about the way the filament cooled. My question was about how it heated. They're related but they're not the same. Also we both seem to think you get a half-cycle for cooling. I think for turn-on-at-zero you get a quarter cycle the first time. Further, if we look at what you said here, >describes that I observed a *significant* change in the and compare to the actual quote, >With a diode in series one can actually see a distortion in I know it could be splitting hairs, but one implies "Yeah, you can see it" while the other implies "Wow! It's obvious!" It just didn't sound like that big a difference to me. Remember people are claiming a 60W bulb eats 1KW on the first cycle... I wasn't questioning your results and I don't question that your bulbs are lasting longer. But I was looking for some evidence about the turn-on. If you were able to measure the current you should be able to see the large inrush current when it's turned on, and tell us some interesting things about that. Still wondering, Barry -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details. -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body