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 Rank: Pro Groups: Registered
Joined: 30/06/2012 Posts: 205 Points: 577 Location: Dunfermline, Scotland
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Hi Fellow Astronauts, I'm just about to start building the AMT/ERTL Deep Space Nine space station with the fibre optic lighting system & i need a little advice on the bulbs supplied with this model.I read on another forum that they weren't very good & burn out rather quickly so i should buy some bright LEDs instead.I've been on eBay & tried to find LEDs that would be suitable but as i haven't a clue about wiring & electrics i'm abit confused with wants on offer.I think 5mm white LEDs would be fine but i need them prewired with resistors.The model comes with a 6-volt battery pack but i would prefer to use a mains adapter with an ajustable voltage switch set to 6-volts.Also, will all the bulbs have the same brightness or do they lose voltage as the power moves along the bulbs? I've also seen christmas lights that stay lit even after afew of the bulbs have burnt out, is this possible with LEDs as once the model is built & glued together i wont be able to replace dud bulbs? Please, if you know someone with knowledge of lighting models or if you can help me that would be great.I need 14 prewired LEDs in total & i will pay £10-£15 for them.Please PM me if you can help.Thanks guys.Stuart.
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 Rank: Vice-Master     Groups: Registered
Joined: 20/01/2011 Posts: 605 Points: 1,744 Location: Canberra, Australia
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With a resistor per LED, (one way of doing it) they will all stay the same. This wiring diargram will be of some help. The diagram has 2 ways of doing it. Upper one shows just one resistor, lower one shows, (your way) with a resistor per LED. Only thing different I would do is have the resistor between the LED and the +, (positive) wire. 
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Rank: Vice-Master Groups: Registered
Joined: 20/01/2011 Posts: 605 Points: 1,744 Location: Canberra, Australia
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Never seen LEDs prewired with resistors. I'm using 2 AA or AAA batteries for my Hood and Victory with no resistor, no problems with them being damaged.
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Rank: Pro Groups: Registered
Joined: 30/06/2012 Posts: 205 Points: 577 Location: Dunfermline, Scotland
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Thanks guys, alot of good advice that i will use.I now feel less worried about buying some LEDs & giving it ago.Thanks.Stu
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 Rank: Master    Groups: Registered
Joined: 05/09/2012 Posts: 1,400 Points: 4,690 Location: Beaminster, Dorset
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Just a thought Guys, if I was doing a Lighting Project I would incorporate a Variable Resistor, probably in series with a Fixed Resistor. This will allow you to trim the brightness to taste once the Model is complete. P.S. It doesn't matter where the Resistor or Resistors are, as long as the Current has to flow through it.
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Rank: Master Groups: Registered
Joined: 05/09/2012 Posts: 1,400 Points: 4,690 Location: Beaminster, Dorset
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It makes no difference whether a single resistor is used or individual resistors, except that individual resistors allow individual control. As long as the Power Rating of the Resistor is not exceeded, in which case use a bigger (size not Ohms) Resistor with a higher Power Rating(P=VxI), otherwise it will get very Hot. LEDs typically have a small Voltage range, say 3.0V to 3.3V at which they work and over this range the Brightness can vary by around 50%, so a variable resistor needs to be selected to vary the Voltage at the LED over this range, depending on the Supply Voltage and working Current. Another Thought, you could use a Light Variable Resistor and then your Lighting would adjust with the Ambient.
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Rank: Pro Groups: Registered
Joined: 30/06/2012 Posts: 205 Points: 577 Location: Dunfermline, Scotland
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Hi Dominic, I've just been to FastTrackRC's website & i see that they sell LEDs with resistors pre built into them.This should do the trick as alot of the chat on this topic is abit technical & for me the simplest answer will do just fine.Thanks everyone for replying.
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Hi Stupot You beat me to it! I was just going to say that the LEDs that come 'pre-resistored' are equipped with a tiny internal resistor, not a normal sized one already soldered on! It's definately the easier way to go but make sure that the circuit isn't over powered though, the internal resistors can't take as much over-current as a full sized one. You can still add an in-line resistor, (standard or variable) though to control the brightness as well as a simple flasher board if you wanted to include the navigation hazard lights. Check out the Maplin or Hobbys websites, they both have kits which might be useful. Best of Luck Robin First wooden ship: The Grimsby 12 Gun 'Frigate' by Constructo Second: Bounty DelPrado Part Works Third: HMS Victory DelPrado Part Works 1/100 scale Diorama of the Battle of the Brandywine from the American Revolutionary War Diorama of the Battle of New Falkland (unfinished sci-fi), Great War Centenary Diorama of the Messines Ridge Assault Index for the Victory diary is on page 1
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