HarryHotspurIf I used an old computer power supply (and I have plenty of them), what would be the best way to add a dimmer in the circuit?
Rather than adding a dimmer I think you would have to make the power supply a variable supply.
Something like this maybe?
http://www.wikihow.com/Add-Variable-Voltage-to-Your-ATX-Based-Bench-Power-Supply
Thanks Kevin. That looks like something simple enough that I might be able to build it. Just out of curiosity, what would happen if I wired an ordinary household dimmer between the 12v computer power supply output and the string of 2.5 volt Christmas tree bulbs I'm planning to use in my structures? Would that work?
BTW, I think I know how to wire the bulbs (about 50 of them) in a combination of parallel and series such that each bulb gets no more than about 1.5 volts. I've tested them with an old MRC power pack and they seem to work fine.
- Harry
HarryHotspurust out of curiosity, what would happen if I wired an ordinary household dimmer between the 12v computer power supply output and the string of 2.5 volt Christmas tree bulbs I'm planning to use in my structures? Would that work?
I can't say I have tried that but just off the top of my head I would say it won't work well at all and might harm the supply. What is generally done with low voltage household lighting is to install a dimmer on the line, (120V) side before the transformer. You could try that I suppose by wiring a dimmer to the outlet the supply is plugged into. Just be careful not to illuminate yourself! If you are not experienced working with line voltage don't do it. I don't want to read about you in the papers.
Thanks. I never touch anything that's 120 volts. Scares me. But I have an inline dimmer (if that's the correct term) around here somewhere that has a regular 120v wall type plug on one end and a regular plug in socket on the other. I bought it years ago at Lowes and never used it for anything. If I can find it, it seems like the risk to me should be low. If I blow out the transformer, so be it. I've got several more that are just taking up space.
I've tried that before and all it did was blow the fuse in the power supply. Something in the electronics doesn't like partial power. Those dimmers are designed for use with lamps and such, not electronics.
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Lots of good advice here. I've been into electronics for work and play for over 50 years, and still made notes of many of the suggestions. For my 2-cents worth: Decide on a lighting voltage and lamp mounting before starting and stick to it as much as possible. I decided early to light most of the structures on my layout. I found a good deal on some 6V bulbs with leads to start. Later I found a special on 12V bulbs with sockets. Then fell in love with LED lighting. Saw a special on 16V bulbs with adhesive base and leads. etc, etc. I now have 7 different power requirements, 10 if you count animation power, and only a few of them work because of the complexity of wiring and powering such a mess. Still having fun, though!
As was mentioned, running incandescent lamps at reduced voltage increases their life. The life varies as the inverse twelfth power of the applied voltage! I run 12 volt lamps at 9 volts and can expect a 32-fold increase in life. I expect I never will have to replace a lamp.
John
Most transformers have accessory terminals. The esiest way I think is to run your wires from each terminal, (there will be two), under your platform to structure areas. Having purchased lights from a hobby shop, one wire goes to each of the wires from the accessories. Kind of like diagram below. The vertical lines represent the wires from the bulbs. I cut a small hole through the platform where the structure would sit and dropped the bulb wires through to connect to the access. wires. I cut insullation away to connect bulb wires without having to tie wires at each accessory. See second diagram. Each vertical line reps. another accessory.
-----I--------From access. 2nd diagram. --------l-------l-------l---
-----I--------From access. --------l-------l-------l---
I also try to use a seperate transformer so the lights aren't affected by train operation causing dimming of lights. A cheap one will do the job. Hope this helps.
cooltech
dale8chevyss A strand of Christmas bulbs works well for me.
A strand of Christmas bulbs works well for me.
What a great idea!!
go to www.visi.com/~spookshow/lowvcircuit.html he gives a hole list of parts needed to light up alot of lights like 30ish off one power saply
I made a drawing of the circuit. Minimal circuit. Some people use a 10ufd electrolytic capacitor between pin 1 and common/minus side. RS has the capacitor.
I added a series diode to protect against accidental DC reversal, read not paying attention, to the polarity of the applied DC voltage. The diode drops only .7 volt from the 9 volt wall wart.
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.