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What you really need is capacitance.  As large as you can fit.  Track pickup from a caboose or lighted passenger car will not be great unles you have wheel pickup, track sliders and 18 wheels.   What is required is capacitors to act as batteries while the track pickup faulters on you.   Any circuit will do, the capacitor is the magic fix.

Problem arrises  from finding the smallest physical size but largest capacitance possible that fits. This is where your money will dissapear on you.  The new super caps will set you back a few $$.

You will need a bridge rectifier, a voltage regulator (LM317 or sim), capacitor (double the DCC track voltage/ largest capacitance/size you can fit, few resistors  

The following link has from the simple to the deluxe solutions.

CAR LIGHTING CIRCUITS

Marc Fournier, Quebec
 

Flicker free

LED Anti-flicker DCC circuit

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Nice, simple,  Idea with the Zener.

But it seems to be missing a few details to select the components.  

BR1;  A bridge rectifier usually rate  between 50 and 1000V and an Amp output rating. What does that 5.5V mean here. Is it the supported voltage, the output voltage. Not too clear to me. 

.047f seems small to rely on  track pickup when it is hampered by dirty wheels, dirty track, faulty track, to try and obtain  flicker free operation from. The minute the track pickup fails you have no reserve to fall back on 

A Zener diode must have a power rating to it, none provided except, I assume, the Vz value of 5.1V

But Jim hangs out over at the Digitrax support forum quite often.

Marc Fournier, Quebec

============  more than you probably want to know ===========

Zener diode regulator

For low current power supplies a simple voltage regulator can be made with a resistor and a zener diode connected in reverse as shown in the diagram. Zener diodes are rated by their breakdown voltage Vz and maximum power Pz (typically 400mW or 1.3W).

The resistor limits the current (like an LED resistor). The current through the resistor is constant, so when there is no output current all the current flows through the zener diode and its power rating Pz must be large enough to withstand this.

Please see the Diodes page for more information about zener diodes.

Choosing a zener diode and resistor:

1. The zener voltage Vz is the output voltage required
2. The input voltage Vs must be a few volts greater than Vz
   (this is to allow for small fluctuations in Vs due to ripple)
3. The maximum current Imax is the output current required plus 10%
4. The zener power Pz is determined by the maximum current:  Pz >  Vz × Imax
5. The resistor resistance:  R = (Vs - Vz) / Imax
6. The resistor power rating:  P> (Vs - Vz) × Imax

Example: output voltage required is 5V, output current required is 60mA.

1. Vz = 4.7V (nearest value available)
2. Vs = 8V (it must be a few volts greater than Vz)
3. Imax = 66mA (output current plus 10%)
4. Pz> 4.7V × 66mA = 310mW, choose Pz = 400mW
5. R = (8V - 4.7V) / 66mA = 0.05k = 50, choose R = 47
6. Resistor power rating P> (8V - 4.7V) × 66mA = 218mW, choose P = 0.5W

Another solution

Presuming that your flickering is due to temporary loss of contact with the track during movement, a large capacitor would be a good economical solution. The difficulty with that is in order to have a large enough capacitance, you would need electrolytic capacitors. The downside of electrolytic capacitors in a model railroad environment is that the electrolytic capacitors are polarized - one side is positive and the other side is negative and rolling stock can be re-oriented such that the electical positive track could be supplying a negative voltage to the positive side of the capacitor. This is solved by using a full wave rectifier (rectifier bridge). This will reduce the operating voltage for the lights due to a voltage drop of two of the diodes in the bridge. That voltage drop is overcome by the use of LEDs for lighting, rather than incandescent (grain of wheat/grain of rice) lamps. Below is my suggested solution:

 (My Edit):

P.S. Shipping of LEDs from TrainAidsA is about $3,35.

I would normally visit my local Radioshack for the other parts, so I did not calculate shipping on those items.

better (?) source

For components like these, I use

http://www.allelectronics.com

Capacitors: 48c  @

LEDs : $1 /10

Rectifiers:  40c @

Resistors +/-  5c

Some are Not available as single items, but you're not using singles, either.

OK, shipping is $7, but  if you can wait 3-5 days... worth the wait... and you can get SO MUCH  for a buck  more than at the shack!

Non Flickering Lights

Jack from Star, Idaho.  Thanks very much getting my brain straight.    I like the simple circuit using Bills schematic.  Question, will I use the same resistance with dcc and super bright white LED?  Looks very simple and cheap to build.

Resistance and DCC

The 470 ohm resistor is what is recommended for 12 to 16 VDC with the LED i had in the schematic. This will work for both DC and DCC trackage.

Sources

Yes, Peter, you are right about the pricing - there are probably a half dozen or more sources that would beat the prices. Concerning the LED - I presume Jack has one installed already - if not, then the LED from TrainAidsA is what I would normally recommend as a generic package with the warm white coloring. The reason behind the Radioshack recommendation is that they are generally open 7 days a week and usually a short drive from the home in more populous areas. Thanks for giving me the link to allelectronics. Have you found their inventory to be well stocked ? The Radioshack I normally use has at least one of each component that I am looking for, so they are good for single solutions. I don't recall ever buying a bad component from them and I believe they will replace any defective components.

car lighting

UPWilly's seems to be the most simple solution to the flickering problem but, I wonder, will the inrush current be seen by the DCC supply as a short?

Ed

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I order from several sources when I start a project. Allied being one of them and I am in Quebec.  The inventory is clearly called out on their web site, with quantity availlable. I have never had a surprise with them.. Heck I got a free coffee mug off them.  Delivery is quick, resonnable priced.  I just try and keep it under 40$, then it sneaks in.

RS here in Canada (Circuit City) are not what they used to be.  I have not been in to see them in ages.  Nothing beats delivered to the door.  

Marc Fournier, Quebec

Power pickup

Jack - Sorry, I just remembered you were also interested in power pickups. The phosphor/bronze types are also available from TrainAidsA (several types):

trainaidsa.com

TrainAidsA.com is also a reseller on ebay, so you might find some specials - click on their ebay link on their home page.

Marc - the 1000 uFD capacitor I specified is less than 1/2 inch in diameter and less than 3/4 inch long. That should fit easily into the HO rolling stock along with the small rectifier, resistor and LED. If the capacitor seems to be physically too large, then reduce it to 470 uFD.

Radioshack versus Circuit City

Marc - here in the U.S. Circuit City does not exist (at least not in my neighborhood). Radioshack was in business many years before Circuit City was ever known. Jack lives in Idaho. "You're mileage may vary".

Inrush current on DCC

@flyerm65 - Sorry, I did not consider the inrush, since I use DC. To limit the inrush current there should be a 220 to 330 ohm resistor between the rectifier and the capacitor (+) terminals. That should limit the inrush current to less than 1 Amp for about a six to eight lighted car total.

Non-flickering made easy

Jack, give me a few days and I will post info for the easiest, and possibly the cheapest, method to install "non flickering car lights." that does not require other than soldering a battery pack and a switch.  I did it in 1989.

Michael, TTYL

Non-flickering made even easier

Flicker free caboose lighting

I have a clinic on line at http://ssandifer.com/Lay/Howard/Const/LEDMarker/Index.htm showing how I put flicker free caboose lighting in my cabooses. The lighting circuit came from Jim Betz and he will provide the materials if you so desire. The capacitor cost more than all of the other components combined and is the only speciality item. I think my circuit boards cost $4-5 each.

The cap in the circuit

Just to clear up the capacitance stated by the original poster.

The value he shows is .047 F  (Farads, not micro-farads)  Large F is farads, lowercase f is micro.

This is a "super-cap" .047F = 47,000 uf.

Charlie

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Came upon this Ebay seller. Various electronics for DCC.  Sells a small board for lighting.  Look up Ebay item 280622959302.  Seller is Streamlined Backshop Services. Also sells what looks like a smart idea for truck pickup for HO and N scale.

Marc Fournier, Quebec

Non Flickering Car Lighting

Jack,

I had the same problem a few years ago and I tried several circuits.  Some worked better than others.  I came up with a different solution.  I use an appropriate size battery holder and an alkaline battery.  There are so many different size batteries that I found I could fit nearly any brass caboose with operating marker lights.  I have done six brass cabooses with these and they work fine.  They also add a bit of weight to a caboose or tender that could use it anyway. I put an on/off switch in the circuit to extend battery life.  I got this idea from a friend who had a battery in one of his cabooses.  One night while I was visiting he decided to see if the battery still worked.  It did.  He had installed the battery 10 years before!

The advantages are:

I dont have to worry about track pickup

I don't care if the layout is running DC or DCC

I don't even care is the layout is turned on!

I do remove or disconnect the batteries if I am not going to use those cabooses for an extended period of time so the terminals do not corrode.  So far this has not been an issue.

Try it--see if you like it.

Tom

That gave me an idea. Use a

That gave me an idea. Use a CR2032 (or smaller)  3V battery.  You can get  holders for these pill type batts in different sizes and shape  from SM to thru hole. Small and compact, bright leds do not require a resistor at 3V or add a resistor and the battery will last  quite some time, simple enought to replace.

Marc Fournier, Quebec

Rechargeable

Could you use a rechargeable battery and then just plug in the cars between sessions? AAA are real small and inexpensive.

I like UPWilly's

I like UPWilly's diagram...how can I modify it to be directional (caboose marker lights), and to use the 1.5v incandescent bulbs already in some of my cars?  (Most of my caboose have marker lights on both ends of it.)

I guess the tricky part is that even if directional, when you switch directions the "wrong" light will be lit for a while.  Perhaps that can be minimized by using a smaller capacitor?  I just need the lights to stay on momentarily when hitting "dead" spots on the track.

The more I think about it with my limited knowledge two circuits may be necessary.

John

How about this?  

How about this, for directional lighting (marker lights with drumhead)?

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Even if a train is making a backing move, would they change the

lighting?  I can see the point of having the ability of being able to change the end of the caboose that has lights depending on which way the caboose is facing in the train, but directional lighting would change the lights any time the train made a backing move.