 Joined: 10/02/2006(UTC) Posts: 3,997
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 9 users liked this useful post by DaleSchultz
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 Joined: 04/12/2013(UTC) Posts: 2,261 Location: Hobart, Australia
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2 users liked this useful post by PJMärklin
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Joined: 15/10/2006(UTC) Posts: 2,319 Location: Washington, Pacific Northwest
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Its always seemed odd that they are called Light Emitting Diodes, when they really are better named Light Emitting Semiconductors. Because LEDs in general suck at being usable diodes due to their very low failure voltage (Vr) as opposed to a specified break-down (non fatal) voltage (Vbr) (ie you need a diode to protect the diode), and they have a higher forward voltage drop than simple silicon diodes that only have 0.7v forward voltage drops.
They really are semiconductor lights, as they have been designed for their light emitting characteristics and not for diode behavior. |
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2 users liked this useful post by Minok
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Joined: 09/02/2014(UTC)
Posts: 17
Location: SOUTHERN FINLAND, PAIMIO
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Hello/ Terve! In fact, I use LED-resistors directly 2K2- 3K3, 125mW. And each has it´s own resistors. Because the brightness of the LEDs is enough, even to the headlights of the locomotives. LED current typically range 3-5mA. This is a 12V/NEM system. And when I use 5V low- dropout regulators..... Therefore, if 3 LEDs are connected in series and 1 LED is shorted, then then current of other LEDs will increase considerably. Maybe too much. It is also easier to find fault with separate resistors. Best regards from Finland. ealab Edited by user 12 May 2017 08:04:00(UTC)
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Joined: 22/01/2009(UTC) Posts: 14,874 Location: On 1965 Märklin Boulevard just around from Roco Square
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since I've been converting loco to digital I've been using Led's, first I started of with 1,8mm tower and 3mm round and some 5mm for the Santa Fe diesel loco's headlights but things have improved since than and I use mainly smd leds with various sizes, from 604 to 1200 and the same goes for resistors, they take up much less room.
I've converted many carriages with led lights and some of them amount to 10-12 carriages, all having about 12 led's within. these are divided into 4 groups (3 led's each) and all my carriage lights are powered by the loco decoder via electrical couplings.
instead of buying expensive interior lights I make them myself, for open car carriages I use led strips and for compartment coarches I make them up myself, configure them in such a way that toilet, gangway and individual compartment are all lit in the right place, it also gives me the choice of leaving some compartment without light, like the prototype.
having an enormous amount of passenger carriages it would have cost me an arm and a leg and by doing it yourself helped me keeping the costs down.
for instance I've just working on a SBB Re 460 with Swiss light change and added red marker lights either single or double.
regards.,
John
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Joined: 15/10/2006(UTC) Posts: 2,319 Location: Washington, Pacific Northwest
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Originally Posted by: river6109  all my carriage lights are powered by the loco decoder via electrical couplings.
Is there a how-to or lessons learned from this endevour? My plan is also to run power out of the Lok via its decoder to a micro-relay to the couplers. Beyond the "how difficult/easy was it to find the tap on the factory decoder to pull power from", and the "whats the wiring inside the loco needed"... any tips would be appreciated. |
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1 user liked this useful post by Minok
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 Joined: 20/01/2015(UTC) Posts: 1,201 Location: Kerikeri
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thanks guys. this is an interesting subject in which I will be getting stuck into during the coming winter. Very helpful
I will be working on analogue engines/loco's and my problem I will be dealing with is how to switch the circuit for the change of direction of head lights, without having to make up a mickey mouse reversing switch. If anyone knows of a micro switch that will work in ac, i would appreciate the help in locating something.
Dereck |
Northland. NZ REMEMBER 0228 for ä |
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Joined: 22/01/2009(UTC) Posts: 14,874 Location: On 1965 Märklin Boulevard just around from Roco Square
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Originally Posted by: Minok Originally Posted by: river6109 all my carriage lights are powered by the loco decoder via electrical couplings.
Is there a how-to or lessons learned from this endevour? My plan is also to run power out of the Lok via its decoder to a micro-relay to the couplers. Beyond the "how difficult/easy was it to find the tap on the factory decoder to pull power from", and the "whats the wiring inside the loco needed"... any tips would be appreciated. I didn't want to continue here so I set up a new topic under Workshop = wiring regards., John |
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1 user liked this useful post by river6109
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