"I would turn the lights on using a slow ramp up from "dim", I think the life of any bulb would be extended. Maybe the bulb manufacturers "influenced" the design. I have had *extremely* good luck using the X10 light-switch style controller on a filament style bulb - going on years now for the same hallway (leading to the nightime quarters) lamp used daily ... 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 I experimented with the current inrush phenomenon at turn-on as seen on filament-style lamps years back with a scope and small-valued series resistor for current observation. I also investigated what ocurred with a series diode in place. With a diode in series one can actually see a distortion in the sine wave current-profile during the 'on' half cycle as the filament apparently cools off during the 'off' half cycle and draws more current during the on half cycle owing to it's lowered resistance. Of course, I need not mention the very high currents occasionally seen when reandomly throwing the swich to on and happening to catch the incoming AC mains sinusoid at a maxima. Jim ----- Original Message ----- From: "Barry Gershenfeld" To: Sent: Monday, July 02, 2001 12:53 PM Subject: Re: [EE]: Bulb Life (x:Modulating headlight) >An update - it's been around 5 months since I added 47R 10W >resistors to my 240VAC wall lights, and so far not one has blown. Two light bulb preserving ideas: 1. I used to see, in those gift catalogues, a small disc-shaped device that you put into the base under bulb. It was a thermistor, such that the cold resistance was high, and once the lamp was on it would heat up, drop resistance and give you full brightness. 2. I have always thought that the one place that X-10 "blew it" was that you cannot start a dimmer up from zero. If the things would turn the lights on using a slow ramp up from "dim", I think the life of any bulb would be extended. Maybe the bulb manufacturers "influenced" the design. Barry -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.