In this past weekend's WPF thread (Dec 5,6,7 2014) I posted a picture of one of a fleet of cabooses that I am working on. JaBear asked me to start a thread showing the wiring diagram for the working marker lights and interior light.
I cannot take credit for the original wiring scheme. That goes to Mark R. I have modified it a bit to adjust the brilliance of the interior light down quite a bit, and I have added in a magnetic off/on switch.
Here is Mark R.'s original diagram:
EDIT: For those not sure of the electronic symbols, The round circle on the lower left with the + and - and two sqwiggles is the bridge rectifier. The rectifier is marked for output polarity. The markings may require a magnifying glass to see. Track power polarity doesn't matter. Note that the right side wire going from the track power to the top of the rectifier does NOT connect to the wire coming off the negative side of the rectifier!
The black bar at the top is the resistor. Polarity doesn't matter.
The center component with the flat line over the curved line is the capacitor. The capacitor will have the polarity marked on it but they don't always use + and - signs. Sometimes there is a black stripe down the side of the case adjacent to the negative post.
The LEDs are on the right of the diagram. They will have one lead longer than the other. The long lead is +.
To quote Mark R. : "The resistor is 1000 ohms and the capacitor is a supercap with a rating of 0.10 farads (not micro-farads) and a voltage rating of 5 volts. I can get away with the 5 volt rating on the capacitor because the resistor is in line BEFORE the capacitor lowering the voltage to acceptable levels for both the cap and the LEDs at the same time. The physical size of this capacitor is about the same as four dimes stacked together. Be sure to observe the polarity..."
I added an 847 ohm 1/4 watt resistor in front of the LED which will be used for interior lighting. I want it to suggest an oil lamp over the conductor's desk only. I put the interior LED in a light box so the light only shines out of one window.
I also added in a magnetic reed switch so the lighting can be shut off when the caboose is not in service. It is wired between one side of the track power and one input to the bridge recitifier.
Here is a picture of the turned down LEDs compliments of Mark R. They fit quite nicely into Utah Pacific marker light castings. I fill the castings with gel CA. The CA then holds the LED in place and also serves as a light conduit: Second EDIT: The CA doesn't appear to work as consistantly as a light conduit as I had hoped. When I tested the first caboose everything seemed fine. The marker lights were bright enough. However, I just tested the other seven cabeese and the results are hit and miss. I will have to re-do the marker lights/LED arrangement to get more consistent results. Please stay tuned.
Note that the capacitor takes 10-15 seconds to charge because of the resistor, so when you first test the circuit you have to wait before you will see any light.
Here are the caps on eBay:
http://www.ebay.com/itm/5-pk-Panasonic-Coin-Electrolytic-Capacitor-5-5V-0-1F-75OHM-Super-Ultracapacitor-/121448968111?pt=LH_DefaultDomain_0&hash=item1c46ec2faf
Bridge rectifiers:
http://www.digikey.com/product-search/en?pv721=12&pv69=3&FV=fff40015%2Cfff8052c&k=bridge+rectifier&mnonly=0&newproducts=0&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25
The magnetic reed switch is available from this gentleman. (The reed switch is optional):
http://www.trainelectronics.com/LED_Articles_2007/LED_103/index.htm
The marker lights are from Tomar Industries under their Utah Pacific brand. Unfortunately their website is down so I can't post a link.
Dave