model lighting

I'm someone who mostly works with styrene kits. These days real space and SF ships.
The reason I'm posting here is that I don't have much knowledge
regarding electronics, especially when it comes to mucking about with resistors, etc., while using LEDs for lighting.
I encountered some interesting model railroad lighting accessories at the local Johnny's Toys, which has a huge train section. They had a wide variety of lights and other goodies which I think I may be able to adapt to my models fairly easily and economically.
I figure I can get a decent generic DC adapter from the local Radio Shack. My question right now regards bulb lifetimes: how long do various bulbs last, as long as you don't have them on several hours every day, as you might (say) at a model building contest or convention?
I would think they would display a decent life, as I imagine most railroaders wouldn't be too happy about changing bulbs very often.
Any advice that anyone cares to offer would be deeply appreciated.
thanks!
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CaseyTompkins wrote: I'm someone who mostly works with styrene kits. These days real space and SF ships. The reason I'm posting here is that I don't have much knowledge regarding electronics, especially when it comes to mucking about with resistors, etc., while using LEDs for lighting. I encountered some interesting model railroad lighting accessories at the local Johnny's Toys, which has a huge train section. They had a wide variety of lights and other goodies which I think I may be able to adapt to my models fairly easily and economically. I figure I can get a decent generic DC adapter from the local Radio Shack. My question right now regards bulb lifetimes: how long do various bulbs last, as long as you don't have them on several hours every day, as you might (say) at a model building contest or convention? I would think they would display a decent life, as I imagine most railroaders wouldn't be too happy about changing bulbs very often. Any advice that anyone cares to offer would be deeply appreciated. ---------------------------------------------------- The lights (lamps) should last a very long time (years) if you apply less than the rated voltage.
Here's one way to do the lights:
http://www.billsrailroad.net/bills-lights.html
Bill Bill's Railroad Empire N Scale Model Railroad: http://www.billsrailroad.net Brief History of N Scale: http://www.billsrailroad.net/history/n-scale Model Railroad Bookstore: http://www.billsrailroad.net/bookstore Resources--Links to 1,100 sites: http://www.billsrailroad.net/bills-favorite-links
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On Sat, 25 Jun 2005 03:13:19 GMT, Casey Tompkins

    If you use LEDs chances are they will outlast you. Most rate MTBF in the thousands of hours. I have gear which had among the ea;iest LEDs made and they are still shining bright. Nowdays they are making car head and tail lights as well as police flashlights with LEDs. you have infra red LEDs in your remotes. If you don't use too much power they are as close to immortal as one can imagine. They have totally replaced regular bulbs in my models and almost everything else (once they make good reading light LEDs, there go my fluorescents.
cat
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True, but I was hoping to avoid using them -at first, anyway- so I didn't have to muck around with resistors and such.
I expect I'll end up learning about them, as there are things (such as running lights on ships) for which LEDs are more suitable.
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On Sun, 26 Jun 2005 02:07:17 GMT, Casey Tompkins

    I felt the same way until I figured them out (which is pretty simple) Then I got a whole bunch of them and a bunch of cheap resistors and had at it. for power i used an old computer power supply which i doubt I can ever overload with the LEDs (so, I'm cheap)
                            cat
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Ahh, LEDs aren't hard to work with. You do have to learn how to solder properly tho before you can really put them into models tho otherwise you'll be pulling the models apart to fix your wiring errors. For you, the cheap 25W RadioShack soldering iron will work fine enough. I don't use them becuause my standards of soldering (I work in electronics as a professional) are a lot higher than what that iron can possibly do. Resistors are dirt cheap when you buy them from the right places - RadioShack has a huge markup (cost to me for a typical resistor is a penny a piece and that isn't even for the cheap ones) on them because you are only buying 5 or so at a time - and LEDs are also pretty cheap. I'd suggest that you pick up an elementary electronics instruchion book and learn what the terms mean and the two basic formulas that deal with basic electronics so that you can calculat the right values for resitors and so forth. If you're in a significant sized city, there will probably be an elecronics discount place somewhere in the city that has such parts for a bit less than RadioShack and that is where you should go. I'll note that electronics parts can be bought by price as they all work well irrevelent of the price. Cheap LEDs can be had for less than a dime apiece in quantity. If you let the smoke out on one, you aren't out that much. As for components in general, unless they are rated to run at a particular voltage or current like ICs are, running things like lights and resistors and so forth ilve longer at lower voltages, currents and so forth. For example, an incadescent lamp rated at 12V will last basically forever at something like 8V. Running a 1/4W resistor with 1/10W of power dissipation will also keep it alive forever. I'll also note that thermal stressing of parts can make them fail faster than if you just leave them running - lamps are particularlly susceptible to this as the tungstun in the filaments doesn't like to be stressed in this fashion as the typical failure mechanism of a ligh bulb is the fracturing of the filament due to heat stress. Go buy the cheap stuff and have a ball with it. Lots of people use them in their construchion every day without any problems!
-- Why isn't there an Ozone Hole at the NORTH Pole?
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You will find a handy (and free) LED resistor value calculator here:
http://linear1.org/ckts/led.php
Good luck and happy lighting.
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MERG's LED Tutorial might be helpful:
http://www.merg.org.uk/led/index.htm
Bill Bill's Railroad Empire N Scale Model Railroad: http://www.billsrailroad.net Brief History of N Scale: http://www.billsrailroad.net/history/n-scale Model Railroad Bookstore: http://www.billsrailroad.net/bookstore Resources--Links to 1,100 sites: http://www.billsrailroad.net/bills-favorite-links
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