I went to the All Electronics website www.allelectronics.com and clicked on “transformers” to see what they have. I think I need a 12vdc unit because most bulbs I’m planning to use are 12 volt bulbs, but I’m not exactly sure what milli amps I need. Some of the All Electronic’s units are 200 MA and others are 400 MA. I plan to wire the lights in parallel, meaning each one will light independent of another, if one lamp goes out. I’m guessing that the higher the milli amps, the more lights I can run in parallel before they become too dim. I probably will have literally hundreds of lights on my layout ultimately and I’m expecting to have many, many transformers mounted under the layout supplying power to all those lights.
Am I going in the right direction? Should I be getting a transformer that puts out 12 volts but has higher amps to run more lights? Obviously, I’m not too informed when it comes to lighting and necessary power. In the past, I just used “train-set” power packs and ran as many lights as I could off of each one until the lights got too dim. Then, I just added another power pack and ran more lights.
i hope someone who knows the answer responds, cause i have the similar problem,
mine is i need to know wht i need to get to run 6V lights, i just got 30 of them but did not read the manual until too late. i think i DUH is in order for this one
I’d get something significantly heftier than that. I just brought up www.miniatronics.com and looked at light bulb ratings. Better count on 30-50 milliamps per bulb. That little 200 milliamp transformer will max out at 4 of those, so for a hundred bulbs you’re going to need 25 little transformers. Hmmmm? No, HMMMMM! The humming noise alone will drive you batty.
You might want to search for “power supplies” rather than “transformers.” I’m running some of my stuff on wall-warts, those annoying power modules that plug into small electronics gadgets like computer speakers, and take up the entire wall socket or 3 slots on your terminal strip. A number of people have recommended old computer power supplies, which put out a lot of power and are generally dirt cheap, since they usually outlast the computer they were bought for.
Final note - don’t run your 12-volt bulbs at 12 volts, or you will be forever replacing them. Run them at 10 or even 8 volts. For things like street lights, this is adequate to give the “illusion” of lights without overpowering your layout. Lower voltage will provide a nice glow to interior lighting, too, and will run cooler inside the closed structures. I’m running a bunch of 16-volt bulbs at 10 volts and I’m happy with the appearance.
See the section about parallel resistive circuits and apply the concepts to what you are doing. Just remember, if an electric load uses electric power, it MUST have resistance!
For bulbs in parallel, their amperage draw is cumulative. 4 bulbs at 50mA will total around 200mA.
Also, I agree with MisterBeasly on not running the bulbs at rated voltage. Shoot for 50-70% of rated. Aka, 16Vdc bulb on a 12Vdc circuit. Change of brightness as a function of change of applied voltage is an exponential decrease. Diminishing return on investment, if you will.
Lastly, you might be better off looking into some bigger DC power supplies, along the lines of 3-5A (3,000-5,000mA). Even radio$hack carries some of the bigger ones!
I’m using a hefty MRC Railpower 1370 power pack to run some of my 12V layout lighting.
The nice thing about using a power pack is that you can dial down the voltage so that you aren’t running your lights are full power. As mentioned, they’ll last a lot longer that way. I picked up one off of eBay for $20.
Thanks for posting that link again! I remember when you were first putting that all together and wished that I had bookmarked it for my reconds. Now I can. [:)]
No problem. Been consumed with other real life shtuffs so I have had next to no time to work on hobbies. Still am planning on working more on that tutorial as time permits.
A old power supply out of a computer is perfect for building lights on a layout because they are usually regulated DC at a fairly high amperage output, so one power supply can be used for hundreds of bulbs. I use the 12 Volt outputs for Tortoise switch motors and building lights, and the 5 Volt output to power LEDs.
Thank you, thank you, thank you. I am currently working on a new diorama that will include a wood working complex. Hopefully with lighting and sound. This has come at the most opportune time. Checked out both links although quite breifly as I am still at work. Will check them out in more depth later.
I just purchased one of these http://www.web-tronics.com/2ampmuposup.html for supplying power to Miniatronics 14v bulbs in my structures. It’s cheap, simple and serves my purposes.
Old/spare transformers for a train are good for powering accesories. First they typically have several amps of power so they will light a fair number of bulbs. Second, if you use the variable track voltage to light bulbs, you can vary the output to accomodate the number of bulbs you have connected and their brightness. And they tend to be no more expensive than other options.
Thanks to my sister, the yard sale fanatic, I have a bunch of Bachmann and Life-Like toy train transformers. I also have a homemade supply based on a Radio Shack filament transformer (6.3 and 12.6VAC, 3 amps, good for bulbs as-is, plus a rectified circuit for CD turnout control.) They are a lot more powerful than wall warts and a lot more flexible as well. And, I couldn’t beat the prices! (usually included some sectional or flex track, and potential kitbash materials, for five bucks on average.)
I use a 220 watt power supply. the 12 volts side is used for my switch machines (tortoises) and the 5 volt side is used for my layout lighting.
A word of caution about computer power supplies. They generally need some sort of load on them at all times to work properly. I Suggest you go to your local auto parts and pick up a cheap brake or turn signal light. those tend to work very nicely.
Computer power Supplies are nice becuase they are regulated. If you add more the line voltage will still stay at 12. My Power supply is 5 amps on the 5v side so that is plenty of juice.
A ‘Transoformer’ is rated in Watts. A DC supply is also rated in Watts - or VA’s (same thing). ILLUMIATION is generally in milliamps.
WHAT you have to watch out for is matching voltages, and staying under the amperage rating, so
HOW MANY lights are you ultimately going to power, and what is their power consumption? Not what someone else uses. 400 ma is not much power, even if it sounds it. It would not throw an Atlas switch machine reliably.
I USE 9 - 6 Volt bulbs in my round house and I pull 5 amps on a 5V supply (5X5= 25VUs. or watts -See what I mean?
if you wire in parallel a 12 volt supply is fine. Not knowing the ammperage needs I’d recomment the higher of any supplys. I would need more than 400 milliamps.
I think you’ll need 5 + AMPS. (“100 bulbs”?) I think not. better to have ‘dim’ bulbs than a power supply catch on fire. Think On/Off switch and fused supply
Illlumination translates exponentionally into wattage.
I’m not sure what you’re saying above. It’s a little too “cryptic” for my thinking. Are you saying that I will need 5 amps for 100 bulbs? Based on earlier input, a 12 volt bulb requires around 50 milliamps. Thus, 20 bulbs would require 1000 miliamps or 1 amp. If that’s true, then 100 bulbs would require 5 amps, which I think is what you said. Then you said “I think not” and I wonder what that means? You said “better to have dim bulbs than a fire”. I wish you would explain a little more. Are you suggesting that I should have several smaller power supplies for groups of bulbs rather than trying to power all 100 bulbs from one 5-amp power supply?
Don, there are others on this forum that are as uninformed as me and probably would benefit from a more detailed explanantion. If you’re going to warn people about a potential fire hazard, it would be good to explain.
