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? I used that as *evidence* that the filament does cool sufficiently to change it's resistance characteristics - and it can do so in the time of one/half cycle. Did I not convey that idea in my original post? Also, the fact that I've got a bulb with years on it *yet* several cycles a day should also lend credence to some method or mechanism in the X10 wall-switch module that prevent a FULL 170 Volts peak from being applied to a *cold* (amd low resistance) filament at random. Jim ----- Original Message ----- From: "Barry Gershenfeld" To: Sent: Tuesday, July 03, 2001 1:23 PM Subject: Re: [EE]: Bulb Life, X-10 turn-on would seem to up life >I *think* (i.e., not proven and not measured) that a >built-in zero crossover detector is what does the trick >in the X-10 wall switch module. > >This allows the bulb to start at *zero* volts on any >given sinusoid versus a possible mid-maxima point where >the peak for a nominal 120 V RMS household US system >is around 170 Volts peak ... *this* no doubt does the >trick in prolonging bulb life At 60 Hz the filament must heat up pretty fast to not mind the fact that you reach full voltage in 4 milli- seconds. Anyone know how long it takes to heat up the filament? (To where it's "warm enough")? 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 hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.