using a MTH or Lionel transformer on acc. Can you use LED lights that are rated 12V DC. If so Is thier any special instr. or tips
thak you
scottyh2o
scottyh2o - Welcome to Trains.com!
Darren (BLHS & CRRM Lifetime Member)
Delaware and Hudson Virtual Museum (DHVM), Railroad Adventures (RRAdventures)
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scottyh2o using a MTH or Lionel transformer on acc. Can you use LED lights that are rated 12V DC. If so Is thier any special instr. or tips thak you scottyh2o
Go here these work GREAT I am using them in two engines and plan to use more. I use the 3mm for headlights.
http://www.modeltrainsoftware.com/bl-213-f.html
Tks,
Kev.
Joined 1-21-2011 TCA 13-68614
Kev, From The North Bluff Above Marseilles IL.
Sorry I poasted the link for flashing lights. Here is the home page.
http://www.modeltrainsoftware.com/ledlights1.html
Kev
I roll my own LED lighting circuits. For AC operation, all you need is the LED, a correct value resistor, and a silicon diode. If you have uni-polar DC, drop the diode. For bi-polar DC, use a bridge rectifier.
I thought DC was DC. What is the difference between uni-polar DC and bi-polar DC?
I've never heard those terms. I think he may be thinking about half-wave and full-wave DC.
Half-wave DC is what you get with a single rectifier in series with an AC source. It is simply every other half-cycle of the AC. Full-wave DC has every half-cycle, but with the polarity of every other half-cycle reversed. You can make full-wave DC with a bridge rectifier. You can also make it with a center-tapped transformer secondary winding.
Whatever kind of DC you have, putting 12 volts across an LED will destroy it immediately. You need a ballast resistor in series. You can buy assemblies, often done up to resemble incandescent lamps, that include a ballast resistor. With no more than that, you must run them on DC.
However, if the manufacturer put some other stuff in there, you may be able to use AC too. One addition is a series diode, which protects the LED from reverse voltage and therefore lets it be run on AC as well as DC. A surer protection is a diode in anti-parallel with the LED; but this draws more current when you run on AC and requires a bigger resistor. For AC operation, a very economical circuit is two LEDs in anti-parallel with a single resistor and no diode. It will run on DC too; but only one LED will light.
Bob Nelson
Thank you for the additional info. I had an electrical course many years ago, so I've forgotten most of it. I'll need to study up before I start working with LED's.
If you are lazy like me these have all of the right stuff already attached and all you do is hook up the two wires anyway you want and they work just fine. No working with LED,s.
Or as suggested you can roll your own.
If your DC reverses polarity, you need to use the bridge to allow the LED to always get the same polarity. This is usually a real issue with the HO folks, or anyone running on DC track power.
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