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Discussion Starter · #1 ·
Hi Guys

What do i need to run LED's off the 16v ac supply from the track please.

Lots of snow falling, what better excuse to go up into the attic and power up


Thanks
 

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I think there are used in all applications,they have been used in industry,car,home so I dont think there to fussy. But dont quote me on it ,give it a try.
 

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Dogsbody
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Run the LED's off a DC supply with a suitable resistor to drop the voltage down to the LED's requirements.

You can run them on AC if you put a rectifier into the circuit to convert it to DC. (A simple rectifier can be made from four diodes.)

I found the easiest solution was to use an old cell 'phone charger so the my LED signals had a totally seperate supply !
 

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QUOTE (BobB @ 13 Feb 2009, 12:57) <{POST_SNAPBACK}>Run the LED's off a DC supply with a suitable resistor to drop the voltage down to the LED's requirements.

You can run them on AC if you put a rectifier into the circuit to convert it to DC. (A simple rectifier can be made from four diodes.)

I found the easiest solution was to use an old cell 'phone charger so the my LED signals had a totally seperate supply !
I've got five of these cell phone chargers wired into my layout,they are usefull as the ones I use range from 3.2vs upto 5.8vs,good for small bits of lighting etc...
 

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Just another modeller
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***Hi YP.

Its not good practice to wire too many things to the track bus, but you can do it if you wish.... LEDs are stablke devices and consume very little power.

As its an alternating polarity with DCC (but in fact not truly "AC" as you quoted - its a much higher frequency square wave) you have two choices.

(1) A full bridge rectifier before the LED and a resistor in series with it (1k would be safe for all colours)
(2) A single standard diode reverse wired across the LED plus a resistor in series with it (The reverse diode protects the LED from reverse voltage peaks which will quickly damage an LED). In this case the LED will actually turn on and off at the same frequency as the DCC signal, but you will not really notice it as DCC frequency is quite high.

To be honest I think the simplest and best answer really is to adopt Bobs suggestion - use an otherwise no longer needed DC wall power supply such as a mobile charger or similar.

Richard

QUOTE (York Puffer @ 12 Feb 2009, 23:00) <{POST_SNAPBACK}>Hi Guys

What do i need to run LED's off the 16v ac supply from the track please.

Lots of snow falling, what better excuse to go up into the attic and power up


Thanks
 

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Discussion Starter · #8 ·
Electronics and can of worms spring to mind, my original intention was to use the switch rail to power an LED to indicate the point had changed, simple with 12v dc, with DCC not so.

How can you get an LED indicator of a point change?

Prefer not to go the full DCC accessory switching route as yet, I like LEDs and switches.

Ta.
 

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Just another modeller
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*** Most of us still use switches by preference.

You will need some form of accessory switch if you want it to be changed by the point - use the mobile phone supply direct to one leg of the LED, via the switch & resistor to the other. Simple.

LEDS need resistors no matter how you power them, so doing it this way is as simple on DC as DCC (you can't use track power on DC or the LED will be off unless you drive a loco in the block!)

Richard
 

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I wanted to have a visual indication at each point to show which lane was clear for the train to enter a point, as I sit at the far end of the layout next to my point changing board.

The LED's I use are 12v ones. They have built in resistors. Strangely enough, they work either way round so there is no problem with polarity. No diodes needed, no resistors needed, just wire them across the track.

To wire up a point, you need to remove the fishplates from the track section that fits into the two pieces of track going into the frog of the point. ( the centre V ). Replace these with insulated fishplates.

You now need to solder wires to all four pieces of track on the point between the switch plates and the frog. The best place is about 20mm away from the frog.

Solder a wire to the outside of each of the outer rails, The inner two rails are soldered on the side nearest the outer rail. Think of where the wheels run, and you will see what I mean.

When wiring up the LED, use one of the outer wires, and the furthest away inner wire to each LED. If the wrong LED lights up, just swop the pair over.

Drop the wires under the baseboard, to connect either to LED's next to the track as I have, or run a wire to a control board. I prefer the visual effect at the point.

If the train stops after the insulated section of the point, just solder in a pair of power droppers to reconnect the power.

The LED's I use are from Maplins, and are RED - CJ63, GREEN - CJ62.

I have a Red LED situated either side of the track going into or out of a point. The LED's are connected to the opposite rail, so that when a point is in postition 1, the LED in postion 2 lights up, telling me that trains path is blocked. Switching the point changes the lights over.

The current they use, ( I have twelve lit at any one time) is negligible.

They have been running for a year now with no problems.

A 12v LED can also be used connected to a pair of crodile clips to connect to the track to see if you have power. Simpler than a meter.

AlanB
 

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I had a new section that I put in recently that consisted of two right hand points connected together. So the train came along, and could be switched via the first point to platform 3, or by reswitching the first point, and setting the second point to platform 1. Both points switched to straight, sent the train off down a main line.

I thought about the red light system as used on the other single points, but it was not going to work so easy on the two connected together.

On thinking about it, I realised that the train would never crash, not like in the previous problem when a point would be against it. It would go on route 1, 2, or 3.
I just needed a light to tell me which route was set.

In this case, I used GREEN Led's. The 12volt ones as mentioned in my previous post.
On the first route to the right on point 1, I removed the fishplate at the end of the first piece of track connected to the point (away from the point), and replaced it with an insulated one. Put it on the rail which is broken by the switch rail, not the rail that is continuous.
You then solder wires to both rails and drop through the baseboard. I then placed a 12v led next to the track, and wired it in. When the point is set in that direction, the voltage goes down the track and lights the LED.

Do exactly the same for the second point, and also on the straight section onto the main line.

Again, do not use point clips. If you lose power on the other side of the insulated section, just wire in droppers.

The reason I used GREEN led's is because in this way of wiring, you are indicating which section is live, and therefore which direction the train is going in.

When the first point is set to right, only that led lights. The others have no power. They change as each point switches. So by glancing over at which light is lit you get an
immediate indication of which route is set.

AlanB
 

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My pleasure.

It is one of those things you find out by trial and error.

I wired my green ones up today as I explained in my second post, and they work fine.

To save working out which rail requires the insulated fishplate, I put one on each rail. No problems.

You can put the drop wires anywhere along the length of rail between the point and the insulated fishplates.
The LED goes anywhere along the side of the track that suits.

A tip when wiring. Put the wire from the rails up through the hole you have made for the LED. ( It only needs to be large enough to take the wires). It is easier to solder.
Insulate one leg of the LED with either shrink tube, or strip off some insulation from the same size wire. Solder the two wires to the LED, and then push down the hole.
My board is 15mm thick, so the wires protrude from the bottom. I then spread the led wires apart. If your board is thicker, you will have to insulate both wires with shrink tube.

If the led is close to you, you will get plenty of brightness. However, if it is some distance away ( I am in the loft ), you lose a lot of the light. I bend the led over to face towards me, and you get the full brightness.

I use the 5mm size SB.

Happy hunting,

AlanB
 
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