Re: Coach Lighting

John Cahill

Don, I may have mis-described initially.  I was trying NO rectification and feeding direct track DCC voltage into the LED strip.  You have explained the need for a 50V diode in line with a suitable rated resistor to that circuit to protect the LEDs.  I will use this going forward. Don't really want to put a big cap in coaches (weight, size, cost factors}. However, I recall a drawing of a lighting circuit I found on line a few years ago which showed a zener across the rectifier outputs and a small supercap in parallel for flicker free lighting.  Does this make sense?  Voltage was around 5.5V out of zener, if I remember correctly, but my knowledge of electronics is rather basic, I'm afraid.

On Thu, Jan 30, 2014 at 7:52 AM, John Cahill <johncahill25@...> wrote:
Thanks Everyone for your helpful suggestions. I'm learning slowly! Will now add 1N4001's + resistor in circuit. 
Can anyone add thoughts on using super capacitors in the circuit for flicker free operation instead of a battery?

Best Regards,

On Jan 29, 2014, at 22:11, John Cahill <johncahill25@...> wrote:

Thanks John. I'm using DCC and a strip of LEDs, about 12 diodes on strip (varies for different makes of coach).  I'm a bit unsure how to calculate current draw other than measuring it as no data sheet for LEDs in question. From that I can get wattage, right?
I also have some supercapacitors I'd like to use to eliminate flicker, but they are rated 5.6V, I believe. Is there a way to work them into the circuit or is that a bridge (no pun intended) too far?

Best Regards,

On Jan 29, 2014, at 19:34, john.p.dunn@... wrote:


   Unless you add a battery (like Spectrum cars), your only option is track power. If you run your cars on DC you will have to power your lamps through a rectifier and use a capacitor to keep the brightness constant. On DCC, forget the rectifier and if you use LEDs you just need a resistor. They are their own rectifier. Bulbs draw more current usually and need a heavier wattage resistor.
   You need to know the wattage, amps and volts of your lamps and use Ohm's law to figure your resister and the total wattage tells you the size resistor you need (1/8, 1/4, 1/2 watt and the resistance in ohms.
   Another option is to put LEDs or bulbs in series to equal your track voltage, of course if one bulb goes you are in the dark.
   Hope it helps.

 From: John Cahill <johncahill25@...>
To: WiringForDCC@...
Sent: Wednesday, January 29, 2014 1:25 PM
Subject: [WiringForDCC] Coach Lighting

Hi! I am investigating the multiple possible methods of lighting coaches/carriages on my HO NCE controlled layout.  I have tried Flicker Free, which works fine.  I have also built small circuits using miniature rectifiers feeding LED strips.  In order to light my entire collection using any of these methods, a significant investment in time and electronic components would be required.  I have tried a small experiment using direct DCC track power to light a short strip of LED lights and found it worked fine, especially with the addition of a 1K resistor in series in the circuit.  Is this approach too simplistic or am I missing something?  Any comments appreciated!  Thanks in advance,
John Cahill

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