I've never seen one to be fitted between a normal bayonet lamp bulb and its socket. We did have things called 'Brimistors' which were self-heating negative tempeature coefficient thermistors, basically, and which were designed for surge limiting. Some radios (and TVs?) had them wired in series with the heater string, whether they did any real goof is a moot point ;-) The other place they were commonly used was in series with mains projector lamps (before the advent of the quartz-halogent projector bulb). -tony

On 28 Jul 2007 at 19:06, Dave McGuire wrote: Those were later, when silicon power diodes got to be cheap. The earlier models had a negative temp coefficient hunk of carbon that actually did a better job of things, rather than lopping off alternate half-cycles. Those diode-in-a-button gizmos were worse than useless. Not only did they cut the power comsumption by *less* than half (cooler tungsten has less resistance), but it shifted the radiated spectrum toward the red something awful, so you got less than half the visible light. You still see something like this in "extra long life" incandescents. Usually rated for somewhere around 135 volts, so running them on 120v resulted in a cooler filament--and orange light. Hopefully, we'll be rid of these things with the proliferation of cheap CFLs. OTOH, RCA during WWII ran extensive advertisements advising running transmitting tubes on 90% rated filament voltage. The claim was made that one could run the tube at nearly full power with greatly increased filament life. Tubes were hard to get unless you were part of the defense effort. Cheers, Chuck

On 28 Jul 2007 at 21:44, der Mouse wrote: You mean, like they've already been doing with 4' and 8' fluorescent bulbs? This isn't a battle worth fighting. Folks drop used NiCd cells in the trash already, not to mention bunches of electronics with lead-bearing solder. I wonder how many folks dispose of old TVs and monitors by smashing the bottle open? How many pounds of lead does a 27" CRT have in the frit seal? Cheers, Chuck

On 28 Jul 2007 at 22:12, dwight elvey wrote: Nope, most of the lead (and particularly the leachable lead) is in the funnel (including frit). The panel contributes almost nothing to the lead leachate. Frit can be as much as 85% lead. See: http://www.pca.state.mn.us/oea/stewardship/es0009020.pdf Cheers, Chuck

On 7/28/07, Dave McGuire <mcguire at neurotica.com> wrote: Dim, yellow, _flickering_ light. ;-) Sometime in the late 1960s or early 1970s, my dad made a "light dimmer" that was just a metal project box, a diode (half-wave rectifier) and a toggle switch. Flip the switch for full brightness, flip again for "dim". It worked fine, for what it was, but the dim light wasn't that good to read by. -ethan

Um, you have the frequencies halved. Normal incandescent light flicker is 120Hz; with a diode, 60Hz. (100 and 50 for 50Hz power, of course.) /~\ The ASCII der Mouse \ / Ribbon Campaign X Against HTML mouse at rodents.montreal.qc.ca / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B

Because there are two brightness peaks per cycle of power; in terms of the voltage of one wire relative to the other, one for the positive peak and one for the negative peak. (And, of course, two brightness valleys, corresponding to the two zero-crossings, per cycle.) The diode, of course, cuts off one of the peaks, replacing it, and the valley on either side of it, by a single extra-wide valley. If I understand you correctly here, that's a "yes". /~\ The ASCII der Mouse \ / Ribbon Campaign X Against HTML mouse at rodents.montreal.qc.ca / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B

On Saturday 28 July 2007 14:24, Chuck Guzis wrote: A friend of mine had one of those that was some sort of a thermistor, you'd turn the lamp on and could see it come up to full brightness way more gradually than was usual. I've also seen some containing some sort of a diode in them. And flashers. -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin