I have a 6 volt power supply left over from a dead router. Will this work with both 12 - 16 volt bulbs?
There will be a large number of bulbs connected to it. I want the lights to be very dim.
I also have a couple of 12 volt power supplies too.
And does it really matter in this application which is the positive or negative? If so how do you tell them apart.
Bob
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If you are using incandescent lamps, they do not care which pole is which, if you are using LEDs it does matter but it is not likely that you will get "dim" out of these things no matter what you do.
The 6 volt power supply is just fine and the incandescent lamps will be dim. Alternatively, you can use the 12 volt supply and wire the lamps by pairs in series.
You should be able to light a goodly number of such lamps with a standard wall-wart, but sooner or later you will overload the thing, and it will begin to run hot. Then you will know that you have too many lamps on it. Or you could figure out amps and milli-amps and wrap you head up with useless numbers that never add up anyway. You may wish to use several of these wall-warts since as you say, you will have lots of lamps. Maybe a separate wall wart for each village or section.
Or you can emulate the LION and provide a 10 amp power supply and light up the whole world.
BTW: Even a small power supply will light 100s of LEDs, but unless you cough up some hairballs with numbers in them, you'll not really get them to run "dim". When the LION is done lighting his railroad (with LEDs) there will be no need to turn the room lights on even at night.
ROAR
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Here there be cats. LIONS with CAMERAS
All the information you need to know about the power supply should be printed on the case. There should be a little diagram that tells you the polarity of the ring and tip of the plug attached to it (which is irrelevant if using bulbs). The case should also tell you the milli-amp rating of the supply.
A few important factors though. If you test the voltage on the plug, is it the same as the voltage rating stated on the unit itself ? If not, the supply is a "non-regulated" variety, meaning the voltage output will vary depending on the load applied to it.
Second, do you know the milli-amp rating of the bulbs you want to use ? A router power supply isn't very robust - probably between 250 and 500 milli-amps. Most tiny model railroad bulbs draw between 20 and 30 milli-amps depending on the bulb, which means you are going to be limited to 8 to 20 bulbs depending on the ratings of the bulbs and the power supply.
Mark.
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12V bulbs will be pretty dim on 6V, and 16V bulbs will barely glow the filament.
How many is "large number"? The power supply from a router is probably under 1 amp, it will say on the label somewhere. You need to know the current rating of the bulbs you are using to calculate how many it will handle. Same for the 12V supplies, do not exceed about 75% of the rating of the power supply - if the power supply says 1 amp, or 1000ma, no more than 750ma of bulbs.
You cna use diodes liek this: http://www.radioshack.com/product/index.jsp?productId=2062591&filterName=Brand&filterValue=RadioShack
to drop the 12V a couple of volts to reduce the brightness. More efficient than using resistors. Each diode will drop .6-.7 volt. So two in series would be 1.2-1.4 volts, etc.
Polarity for incadescent bulbs does not matter. If you use the diodes with a 12V supply, it will matter, because diodes or directional. If you look at the picture, each one has a band at one end. TO wire diodes in series, connect the banded end of one to the non-banded end of the next. Connect one side of the power supply to the diodes, and here's where polarity matters. The non-banded end should go to the power supply positive. However, no harm will be done if you have it backwards, the lights simply will not work, so if the power supply wires are not marked in any way, you can do this by trial and error, one wa it will work, one way it will not. All 4 diodes will get your 12V down to about 9.2V, for lamps that can handle 16V this might be low enough, or maybe still too low, but probably about right. You can add more diodes if it's still too bright, or take some out if it's too dim. FOr under $3 a pack, it's worth experimenting, if you have more lights than a single power supply can handle, once you know what voltage you need (you cna measure it after the diodes and see just what you are getting), you can get a power supply of close to that voltage instead of using 12V plus a string of diodes.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
BroadwayLion You should be able to light a goodly number of such lamps with a standard wall-wart, but sooner or later you will overload the thing, and it will begin to run hot. Then you will know that you have too many lamps on it. Or you could figure out amps and milli-amps and wrap you head up with useless numbers that never add up anyway.
You should be able to light a goodly number of such lamps with a standard wall-wart, but sooner or later you will overload the thing, and it will begin to run hot. Then you will know that you have too many lamps on it. Or you could figure out amps and milli-amps and wrap you head up with useless numbers that never add up anyway.
Load 'er up till it gets hot ! That's pretty poor advice for something that plugs into 110 volts. I've seen melted wall warts and scorched walls. This is still a 110 volt step-down power supply. It's important to know what you are doing when loading these things up.
True enough. But then LIONS do not use wall warts in the train room. Him has a 15 AMP regulated supply for the traction motors, and a 10 amp aux supply for everything else.
Him has never drawn more than 2 amps even with 6 trains (9 engines) running all at once. But LION is part Ruskie, and over engineers lots of things.
Here is transformer of LION. (Train Room is upstairs)
Here are Transfer Switches. House is drawing 31.2 KW at the moment. Emergency Generatror can supply 100 KW.
BroadwayLion True enough. But then LIONS do not use wall warts in the train room. Him has a 15 AMP regulated supply for the traction motors, and a 10 amp aux supply for everything else. Him has never drawn more than 2 amps even with 6 trains (9 engines) running all at once. But LION is part Ruskie, and over engineers lots of things.
And just how does THAT contribute to the topic at hand ???
This third person rhetoric and mindless contributions are REALLY getting tiring. Post count isn't everything.
I started out using old wall-warts and small electronics power supplies, but they are pretty limited. The Miniatronics bulbs I use run 30 milliamps each. 15 of those, and you're basically at the limit of a typical half-amp supply. After a while, you'll have a bunch of separate lighting buses and several terminal strips full of wall-warts.
You're really better off standardizing on one light bulb rating and getting a big supply to cover that. You can get a nice 5-amp, 12 volt supply from All Electronics or another online retailer for about $25. I run all 16-volt bulbs, which give a nice warm glow at 12 volts and they will have a very long life as well. I put a 4-amp fuse in the output line from the supply, because these supplies don't have circuit breakers, and if you overload them the one-time internal fuse, meant to keep your house from burning down, will blow out and you'll be left with a paperweight.
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Randy- I went to RS yesterday and bought a 4-pack of those diodes you mentioned. I hooked up 2 in series to a 13V, 5A PS to reduce the voltage from 13v to 12v. It did the job but both diodes got fairly hot. Is this normal???
mkepler954 Randy- I went to RS yesterday and bought a 4-pack of those diodes you mentioned. I hooked up 2 in series to a 13V, 5A PS to reduce the voltage from 13v to 12v. It did the job but both diodes got fairly hot. Is this normal???
The diodes need to have an amp rating equal to or greater than the load you are running. My guess is that the amp rating of the diodes is too low. They will get warm, but hot is saying they are overloading.
How many lights do you have hooked up? Do you have any idea of the rating? However, even if they are as much as 50ma each, 10 in parallel is still only 1/2 amp, and those diodes are good for 4 ams, so they shouldn't get warm. But if you have 100, that's 5 amps, and exceeds the diode rating. Basically, below half the diode rating shouldn;t get terribly warm. Running right at the limit, yeah, they will get warm.
If you want to do this intelligently, get a couple multimeter's. Get the $5.00 one for voltage, resistance and DC current readings. If you need to read AC current, get the $20.00 one.
Use a cheap one for AC voltge and the $20.00 one for AC currrent.
http://www.harborfreight.com/catalogsearch/result?q=multimeter
http://www.trainelectronics.com/Meter_Workshop/index.htm
http://www.trainelectronics.com/Meter_HF/index.htm
I have three of the cheap ones as I do not use AC voltage for any lighting so I do not have to measure AC current.. I have a version of the $20.00 one but never use it as the cheap ones are light and easy to carry.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
I picked up a 12 volt power transformer at Radio Shack for around 12 dollars several years ago. Puts out around 4 amps. Works fine. I also use an old Lionel transformer for lights. They can be had cheap at train shows, and are adjustable for whatever light intensity you want.
I have several power supplies that I can't figure out what to do with. One is from an old printer, and puts out 30 volts. Another is an old computer power supply, putting out 3, 5 and some other voltages.
I have an ammeter hooked up permanently to the 13V PS and it shows a 1.2A draw. The diodes are rated at 6A, 50V. Maybe I'll just get diodes rated higher and see what happens.