Rich, welcome to the forum, all Led's are powered by DC and when you add AC they flicker, so all you need is a rectifier and you most probably aware of it all Led's need a resistor., the resistor value for each Led should be around 1000ohm

John

240W 12v DC power supply from ebay. $25 or so.

You want to power the turnouts lanterns with AC though, since they have 2 LED's in opposite polarity so if you use DC you only get half the brightness.

If you have an old PC lying about it will contain a very nice DC power supply.

Here is an example of using such a a DC power supply:

https://cabin-layout.mixmox.com/2007/02/dc-power-supply.html

Once you have your DC power, this is how to connect up your LEDs:

https://cabin-layout.mixmox.com/2017/04/led-lighting-circuits.html

If I may challenge this.

The current Marklin Power supplies are not "digital" !!! , and while they may provide power to a controller (CSx or MSx - who then encode a digital signal to the track/accessories) , they may just as well provide power for lighting.

It is desirable (best practice) not to use the same power supply for both a controller and lighting, but it is absolutely possible.
Again some cross-communication is creeping in.

The flickering you originally reported was from the track output (which is digigal) and was NOT due to the high frequency used for of the digital signal itself, but due to the slower variable "packets of data" and the spaces between the packets as well as the different behaviours - e.g. mFX decoder responding to a configuration command - which resulted in different amounts of power at a frequency that the eye can detect.

(As an unrelated comment I find this behavior extremely helpful as it can provide an indication when an mfx detection is occurring )

Connecting a LED to AC (e.g. a good old Blue transformer) would result in a stable 50/60 Hz output that is almost imperceptible to the human eye.
However I would recommend introducing full-wave (bridge) rectification to produce 100/120 Hz. At this frequency you may not even need any smoothing as the eye will not detect it (Read up on the persistence of the human eye)

Todays diodes are quite capable of tolerating a reverse voltage - as long as you have the mandatory current limiting resistor in series.


ANY LED MUST have a current limiting resistor, there is no such thing as a "voltage rating for a LED" (other than the reverse tolerance)

The same LED may be used with different voltage supplies as long as you adjust the resistor accordingly


In summary,
My personal recommendation is to make use of older (good condition) Marklin transformers (no need for a powersupply) for LED lighting.
The Yellow/Brown offers a fixed brightness, while the Red/Brown offers variable brightness.

And, just to reemphasize, a resistor is mandatory, but once you have a minimim value you may increase it to give a dimmer brightness.


Noted Limitations
Perception of flicker
- Dale - movement either head or object looses the benefit of persistence
- Minox - Camera perception - not the same as an eye
Suggested workaround : add a Capacity after the rectification - size would be dependent on the load (for LEDs 100uF )

Design practice
- Per - should not "rely" on a LEDs tolerance of revere voltage
Concur with suggestion : Add a normal diode in series (e.g. 1N4001)

Edited at: by user 22 January 2019 22:45:36(UTC)  | Reason: Noted limitations

Is that so?
If it has 2 leds in oposite direction, the amount of LIGHT should be the same;
2 leds each giving light HALF the time.
-or-
1 led giving light ALL the time.

Just wondering...

Some are; but not all.

If you're not absolutely sure what you buy, spend that diode to prevent reverse voltage.

Per.

I have a small setup so all accessories are powered directly from the C track. The leds and decoders of the 12 turnouts + buildings consume in the order of 0.1-0.2A so it was not worth a separate power supply.

On the other hand I have tried both approaches: directly connecting leds+resistors and going through a rectifier. Didn't see any difference frankly speaking. Can't see any flickering from the DCC signal in either.

In this setup there are however dips in brightness when the M* turnout motors snap. So I've added capacitors to compensate for them. In which case you need a rectifier so I'd suggest at least a diode if not a rectifying bridge to be able to add a capacitor in parallel.

Cheers,

.costin

Thats what I was thinking. I'd imagine the difference in brightness would be due to the voltage differences between the AC and DC signal to some extent, and the dead zone between the AC waves where neither LED is on as the AC voltage hasn't risen above the minimum to fire the LED.

Rich, don't be discouraged by the amount of information. In short you _can_ connect the LEDs to the tracks. Just be careful about the resistor in between (if not included in the part already). But you will need to keep it in mind regardless of the power supply.

You will _not_ have a flicker from the AC track signal (DCC is 8-10kHz so only Chuck Norris can see it flickering).

Cheers,

.costin

Dale,

Thank you !!! I think that will work perfectly. It plugs into the wall, is self contained, and has easy to use outputs that do not require any special plugs or connections. Before I order it, this is my last (stupid) LED question: The Brawa and Viessmann and even the Marklin 74470 turnout lantern call for 16V; is a 12V DC output sufficient? I always thought that generally LED's require 1 or 2 volts to function so I do not understand the 16V requirement. Could "16V" indicate a max voltage?

- Rich

Just a word of warning. The 220/110V connectors on these devices are on the same strip as the lower voltages underneath that orange cover so take great care where you site them (in a clear area - hidden could cause major problems to your health!)

Indeed. These power supplies have exposed line level mounting screws, by itself not a problem. Get a 3 prong power supply cable to go with it and attach it (correctly) to the 3 input lines for ground / hot / neutral.

Your going to ideally want a plastic cover that goes over those leads and prevents accidental touching of the 120/240 v input screws.