ZW Transformer & LED Lights

You will need to add a bridge rectifier to your circuit to the LED. This will convert the AC power from the transformer to DC. You mentioned the LEDs come with dropping resistors so all you will need is the bridge rectifier.

Some one out there can point you in the right direction on which one.

There are several electronic parts companies that have them.

Many years ago I would get them from Radio Shack but I think there electronics days are far gone!

First off, you won't see the flickering, and if it's a problem after you put in the rectifier, you can just use an electrolytic cap to smooth the DC.  You'll want to set the handles down to about 8-9 volts AC with the bridge rectifier, as the DC output will be around 1.4 times the AC RMS value.  Also, with a bridge rectifier, you'll have 120hz pulsating DC, as both sides of the waveform are passed by the bridge.

Digikey is my go-to place for cheap electronics.  They are cheap, have tons of stuff, and shipping for small orders is only a couple of bucks.

I don't understand this LED stuff.   I wanted to replace the headlight bulbs in my Alco from 1993.  My LHS gave me a package of small LEDs and told me to just wire them into the existing circuit that supplies power for the bayonet type bulb.   It worked fine.  I didn't do anything else.  Am I missing something here?

You're missing a lot, but you may have an acceptable substitution of which the LHS knew the details.

What we're missing is what kind of bulbs you bought.  If you had wired a plain LED into that circuit, it would have gone out in a blaze of glory in a flash.  Obviously, you purchased them with some sort of current limiting.

Vinny26,

Nothing like hyjacking a thread LOL!! It sounds as if you purchased one of the newer items on the market. Everything is wired inside one little element.

Just go to modeltrainsoftware.com

  Evan Designs

 All the tech stuff is already figured out for you.

  They sell LED's with the bridge rectifiers and resistors already included.

  Just hook them up to your ZW and your ready to go!

The LED is a DC (polarity sensitive) device so will indeed "flash" on and off 60 times per second as the AC voltage alternates polarity at that rate.  I used to be able to sense this flickering when I was younger but it doesn't bother me now as my brain has slowed. 

Another option is to place two LEDs inside each cabin wired as shown below.  In this back-to-back configuration, one LED turns on during the positive half of the AC and the other turns on during the negative half.  If the two LEDs are placed inside a cabin close together, you won't be able to tell there's 2.  The combined LEDs will "flash" at 120 times per second which I'm pretty sure no one can sense.

Without getting bogged down in technical details, this method also provides the LEDs with so-called "reverse voltage" protection which your eBay guy might have mentioned as another reason for going with a DC supply.