QRModeller Posted January 24, 2012 Share Posted January 24, 2012 Hi everyone, I need a bit of help. Being a numpty when it comes to most all things wiring, I'm unsure whether I should use AC or DC current for layout lighting. Currently, I'm using Gaugemaster 'combi' controllers and I would rather use one of the 16v AC output terminals for layout lighting, rather than fork out for a seperate power source. The thing that confuses me is whenever I'm browsing through light manufacturers catalogues, all of the lights that use LEDs mention DC and the ones that use GoW/GoR bulbs either mention DC or nothing. So, my question, can I use AC provided I use resistors and/or wire the lights in a certain way or do I have to use DC (and use resistors/some funky wiring method)? Help with this would be greatly appreciated. Matt. Link to post Share on other sites More sharing options...
PLD Posted January 24, 2012 Share Posted January 24, 2012 LEDs by definition only allow the current to flow one way through them so DC is recommended. If you attach then to an AC supply, they will light but will flicker on & off (50 times per second on usual 50hz supply). This is almost imperceptible to the human eye, but as the life of LEDs is measured in on/off cycles it won't do any good for their longevity... Link to post Share on other sites More sharing options...
Bruciethefish Posted January 24, 2012 Share Posted January 24, 2012 You could add a diode in the circuit to make the current flow one way only, giving half-wave rectification. This will produce a slight flicker, but at least won't subject led's to reverse polarity pulses, which won't do them any good... Even better would be to add a bridge rectifier (4 diodes) to convert the output to a slightly spiky DC, which can be further smoothed with a capacitor..... Link to post Share on other sites More sharing options...
RMweb Premium kevinlms Posted January 24, 2012 RMweb Premium Share Posted January 24, 2012 Don't forget that when you load up the controllers with lights and other devices, there is less power available for the train. A small number of LED's might not make a difference but many will. Check the ratings plate on the Combi for the total available output. Much better to have a seperate power supply, IMO. Kevin Martin Link to post Share on other sites More sharing options...
RMweb Premium Gwiwer Posted January 24, 2012 RMweb Premium Share Posted January 24, 2012 It can be a better option to purchase a cheap controller or power pack which will convert your mains supply to 12vDC. I use a couple of old and very cheap Hornby controllers with the lighting wired to the uncontrolled 12vDC output (not the train controller) and with a simple on-off switch (in my case a Hornby lever) in the circuit. By this means I have three independant lighting circuits running. When I connect any of those to the main train controller the inbuilt fan slows significantly indicating a loss of current for the intended supply i.e. running trains. Those can also slow down depending on what is running and the load behind it. Link to post Share on other sites More sharing options...
QRModeller Posted January 25, 2012 Author Share Posted January 25, 2012 Thanks for the responses everyone. Looks like I'll be getting a cheap power pack with DC then. Matt. Link to post Share on other sites More sharing options...
RMweb Premium Gwiwer Posted January 25, 2012 RMweb Premium Share Posted January 25, 2012 Another tip before we go ..... Street and platform lighting can use a lot more current than we might expect. You are likely to get far better results wiring in parallel compared with series. For the numpty electricians (which includes myself) I suggest a Google search but in simple terms you run two wires from A to B beside each other (i.e. parallel) and wire each light across from one to the other of those. As opposed to series which is where you simply connect everything end to end in a continuous loop of wire. Parallel wiring can have "dead ends" where you two main feeds don't need to return to anywhere; the circuit is completed by every light fitted across the two. Link to post Share on other sites More sharing options...
QRModeller Posted January 25, 2012 Author Share Posted January 25, 2012 Thanks Gwiwer. I sort of remember something along those lines from when I did science in Yr 10! Matt. Link to post Share on other sites More sharing options...
DonB Posted January 25, 2012 Share Posted January 25, 2012 Another similar topic was at :- http://www.rmweb.co....__fromsearch__1 If running LEDs the link towards the end of the thread (it's only 1 page) directs to a site which will design your circuit for you, including parallel / series combiations and giving resistor values. Link to post Share on other sites More sharing options...
QRModeller Posted January 25, 2012 Author Share Posted January 25, 2012 Thanks Don, that will probably come in handy! Matt. Link to post Share on other sites More sharing options...
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