----- Original Message ----- From: "Erik Reuter" <[EMAIL PROTECTED]> To: "Killer Bs Discussion" <[EMAIL PROTECTED]> Sent: Thursday, June 26, 2003 9:36 PM Subject: Re: [Humor] RE: Question Regarding Religion and Atheism
> Incidentally, on the next page of the link that you found, > > http://home.howstuffworks.com/christmas-lights3.htm > > "The more sophisticated light sets now come with 16-function > controllers that can run the lights in all sorts of interesting > patterns. In these systems, you typically find a controller box that > is driving four separate strands of mini-bulbs. The four strands are > interleaved rather than being one-after-the-other. If you ever take > one of the controller boxes apart, you will find it is very simple. It > contains an integrated circuit and four transistors or triacs -- one > to drive each strand. The integrated circuit simply turns on a triac > to light one of the four strands." > > So it seems it is NOT too expensive to include a simple IC and a few > power transistors in christmas lights. It is amazing how much technology > can be packed into a cheap bit of gadgetry these days. > > On Thu, Jun 26, 2003 at 08:43:26PM -0500, Robert Seeberger wrote: > > > You do know that AC and DC power isnt the same? You require larger > > wire for DC. Work it out from there. > > Your statement is misleading. You CAN hook up a string of Christmas > lights to a DC supply and they will light. The principle here is that > if you apply AC 120 Vrms (about 170V amplitude sine-wave) across a > resistor, the power dissipated is the same as if you apply DC 120V > across that resistor. The PEAK current and voltage will be higher in > the AC case, but the average power is the same. We use the term "effective" power (which delivers the same overall power as the DC average) as opposed to "average" power (the average between peak and zero voltage) which is lower than the DC average. This is standard nomenclature in the electrical industry. > If the AC frequency > were really low, then you would need bigger wire for the AC to handle > the higher peak power. As long as the average power dissipated in the > wire is the same, the same wire will work for both AC and DC. If the > wire works for AC 120 Vrms, then putting DC 120 V on it, plus or minus, > will also work. If you disagree, I'll bet you $100 that I can go to the > store, buy a string of 50 mini-lights, and hook it up to a DC power > supply (I might need to tweak the voltage a little from 120V, depending > on the bulbs) and get it to look just like it does when plugged into a > 120Vac wall socket. And it won't overheat. I'm not disagreeing with what you have written here. But in my industry it is taught that because there are zero power moments between peaks on the sine wave, conductors have time to disappate some of the resistive heat. You use larger conductors for DC power. Its just a fact of life. You are right, the lights will burn, but they won't last as long as they will as part of an AC circuit. Tweaking the voltage to get the same lumens is cheating! <G> > > > As it turns out I was on target regarding the shunt. Actually though > > its just a wire with a resistive coating. > > Yes, that little coated wire is really clever. Whoever thought of that > should have it named after them. Really.....that's brilliant! > > > Out of curiosity I did a bit of research and I cannot find a single > > example of *mini-lights* (the popular kind these days) wired in > > parallel. I was pretty sure I had seen some, but cannot find anyone > > who sells any. > > If I remember, the Christmas light strings (not just individual bulbs) > I saw had a sticker or a little blurb printed on the package that said > "parallel" or "parallel wired" or something like that. > > > The old incandescent type Christmas lights are all wired in parallel, > > but that's not what we were talking about was it? > > The mini-lights are also incandescent. True......I was just trying to differentiate between the styles. > That just means that a heated > filament (or heated something) gives off the light. I thought it meant "glowing"???? > As opposed to > fluorescent or LED lights. When I see a string of lights labeled > as parallel, the circuit shown in the link you found for the old > higher-power Christmas lights is what immediately springs to my > mind. But I'm sure all of us were talking about the lower-power > mini-lights, which as you predicted have a shunt in the bulb. > > Actually, can you buy LED Christmas lights these days? Now that they > make GaN LEDs, you could have white, red, orange, yellow, green, and > blue lights all with LEDs. > I've seen white, red, green, and blue LEDs, but never orange or yellow. I have a few LED flashlights and swear by them. Have you seen the "rice" lights? Exquisite! xponent Light Up My Life Maru rob _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
