Scenic lighting

Discussion in 'FAQs' started by Woodie, Jul 10, 2001.

  1. Woodie

    Woodie Active Member


    I'm currently running 17 GOW bulbs and 4 small bulbs through a 12V DC 1 AMP transformer, with a PWM controller to control the brightness. Used for building lights, platform lights et al. Any ideas on how many lights I could run through the 1 AMP transformer? The transformer is not even getting warm at the mo, so I gather I have a few more to go before reaching capacity?


  2. Gary Pfeil

    Gary Pfeil Active Member

    Woodie, This is not an area of expertise for me, but I believe watts are determined by voltage times amps, so if you know the wattage of the bulbs, add them then divide by 12 (volts) to determine current required. If you know the current draw for the bulbs, you can just add them. You should install a 1 amp fuse on the secondary lead of the xformer to prevent it from overheating if you do overload it. Perhaps someone with better knowledge of electronics can verify this info.

  3. Woodie

    Woodie Active Member

    Thing is Gary, I don't know the wattage of the bulbs. They are ones with Green leads and red leads.... That's all the info I've got! [​IMG]

    Just wanna know is it 200 or 20 that I'll be able to plug in before I blow something up!

  4. Gary Pfeil

    Gary Pfeil Active Member

    Woodie,, In that case, by all means install that fuse! If you have a multi meter, you can hook it up in series with the bulbs and read the current draw (while lamps are lit). This way you will know what your are presently drawing with the 21 bulbs already installed. Then you can determine how many more you can add to reach your 1 amp max. I think you mentioned using a dimmer also. That probably works by varying resistance, so when you use the meter, check the effect of the dimmer also. IE, check current draw at full brightness and again dimmed as low as you go. That 1 amp fuse wired directly in line with one of the xformer outputs will protect your xformer if you overload it. A fuse on the primary side is a good idea also, I can't tell you what its value should be, someone more knowledgeable than I will have to help you here. If you install a fuse holder on that output, you can also put a 1/2 amp fuse in just to see if it blows while you turn on the 21 lamps. If not, then you are still under 1/2 amp. Then try 1/4 amp. If you do not have a meter, try that method.

  5. billk

    billk Active Member

    Woody -
    Your amp draw should be volts/resistance.
    Measure the resistance of the light bulbs, and then add them up as follows:
    Total Resistance = 1 / (1/R1 + 1/R2 + ... 1/Rn)
    so the amp draw would be 12/Total Resistance.
    (I'm assuming the bulbs are wired in parallel)
    Hope this helps
  6. Woodie

    Woodie Active Member

    Thanks guys,

    I'll try a few of those things out. Better get the fuse in place as well!.

  7. Dave Harris

    Dave Harris Member

    Most GOW bulbs are rate in millie amps (100 milliamps = .01 amps) so it would take quite a few to equal 1 amp. I would not connect them in series as 1 failed bulb shuts them all down, ( Christmas lights?) Not my idea of a good time, looking for the bad bulb!!

    L V Dave
  8. shamus

    shamus Registered Member

    Hi Woodie,
    I run around 100 G.O.W. bulbs from one 12v transformer, using only four on/off switches. Even when I put them all on together, the transformer does not get warm. I would think it could handle alot more, I do have an in-line G.O.W. bulb as a fuse, if it blows, I shall replace it. (Hasn't blown yet)


    NARA Member #24
  9. kf4jqd

    kf4jqd Active Member


    I use an old laptop notebook computers power supply. It has an output of 16vdc and about 3amps. I have over hundred lamps. No problems. I like using LED's. They draw much less current. Don't forget that fuse!!!!

    Hmmmmm now you have me thinking Woodie. If I disconnect my 35amp Astron power supply from my VHF/UHF Ham Radio station. That could be alot of lighting!!!!!


    Woodie, remember you can see my LED lighting on my website.
  10. Woodie

    Woodie Active Member

    Bloomin' 'eck!! 35 AMPS.... Any wonder California has power blackouts!! Now we know the cause! Andy turns his ham radio on! hehehehehe [​IMG]
  11. kf4jqd

    kf4jqd Active Member

    A comment to Dave Harris:

    He mentions about not connecting light up in series. I do it to some of my street lights. The reason is they are too bright. The bulbs burn out faster. It is a pain to find out the burned out ones though! [​IMG] I could have used resistors, oh well.

  12. Woodie

    Woodie Active Member

    Just an added note.... I have not connected any of the glodes in series. All are parrellel. I user a cheap PWM controller (kit built) to control the brightness. I have wire inside building lights on a separate circuit to outdoor/street/platform lights so I can control the different levels of brightness required.

  13. kf4jqd

    kf4jqd Active Member


    A simple POT (not the drug! [​IMG]) will do the job and cost less.

  14. Biggerhammer

    Biggerhammer Member

    Or if it didn't work, you still wouldn't care as much :p ;)

    More seriously, I was wondering about simulating moving water using lights. Would it be possible to simulate fast-moving water- such as in the run to a waterwheel- by embedding some optical fibers in the millrace (at the bottom) and putting the other ends in a circle around a flickering bulb? Or have a steady bulb in the middle, a cylinder with many small cutouts around the buld and the ends of the fibers in a cylinder around that?

    Thank you.
  15. Woodie

    Woodie Active Member


    A bit complicated dont you think? But you could always try!
  16. kf4jqd

    kf4jqd Active Member

    Water lights


    The last couple of Christmas's I have gone to Dollywood (Dolly Patron's theme park). They used Christmas motion lights on a water mill and an over head water truss that fills the water tower for the steam locomotive. To answer your question, yes it is possible. You would need lights in motion. I have seen in Walther's catalog or go to they have a light set that can do this. It's called a marque lights. They advertise that they go around billboards. If you are good in electronic building, you could build it yourself.


    This picture is me in front of the steam loco at Dollywood!

    Attached Files:

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