richg1998 I have some bipolar LED's for signals that are 3mm and a kind of white clear case...
I have some bipolar LED's for signals that are 3mm and a kind of white clear case...
richg1998 ... The case is not a color but I see the two LED's down inside the case that are a little green for one and red for the other. Thought I could get a yellowish but never did. Same with DCC...
... The case is not a color but I see the two LED's down inside the case that are a little green for one and red for the other. Thought I could get a yellowish but never did. Same with DCC...
I agree with Randy that it's hard to get a good yellow out of a bipolar LED, but regardless, to get the best yellow you can from one you do not want to use one with a clear case. You want one with a diffused case because it helps to blend the colors together.
LION had some bi-polar LEDs once, but him got them on meds and they are ok now.
LION has DC layout, but him uses reed switches between the rails and a magnet under the locomotives to track the position of the trains. Works Good!
On some tracks the LION uses a FEATHER to detect the trains. Leastwise, that is what I call it. It is a long soft but firm appendage attached to a micro switch. It detects the presence of equipment on the tracks.
Here is what LION built:
Here is circuit that makes it all work. Looks complicated, but if you can plug in a lamp, you can build one of these. There is nothing mysterious in here, no IC chips or somputer stuff. Just relays that go CLICK.
LIONS understand realys that go CLICK.
ROAR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS
richg1998 I have some bipolar LED's for signals that are 3mm and a kind of white clear case. They show all red or green with DC depending on the polarity. I wanted them to show yellowish using a signal from a 555 IC. Never did work. The case is not a color but I see the two LED's down inside the case that are a little green for one and red for the other. Thought I could get a yellowish but never did. Same with DCC. Might vary with brands of LED's. Maybe I was using the wrong frequency. Rich
I have some bipolar LED's for signals that are 3mm and a kind of white clear case. They show all red or green with DC depending on the polarity. I wanted them to show yellowish using a signal from a 555 IC. Never did work. The case is not a color but I see the two LED's down inside the case that are a little green for one and red for the other. Thought I could get a yellowish but never did. Same with DCC.
Might vary with brands of LED's. Maybe I was using the wrong frequency.
Rich
To get a good yellow out of them is hard. You have to adjust the frequency, and also use a non-symmetrical waveform, since the red and green components have differeing light outputs. It's slightly easier to get it right with a 3 lead LED, since you can drive the red and green with different currents. The common green LED is wrong for railroad signals anyway - RR CirKits has a 3-color LED (4 wires) made up using the proper colors for real railroad signals - and explains why the red/green never make a really good yellow no matter what you do: http://www.rr-cirkits.com/Notebook/Searchlight-led.html Luckily my railroad won;t have searchlights, bur rather 3 individual lights in a Type G head.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Stevert Wait, you just want to know if you have a track turned on or off? You don't need LEDs or resistors for that, unless you're going to use push-on/push-off switches. Assuming toggles, just position them so that (for example) up is "On", and down is "Off" That's how I've done mine, except they are labeled for visitors.
Wait, you just want to know if you have a track turned on or off?
You don't need LEDs or resistors for that, unless you're going to use push-on/push-off switches.
Assuming toggles, just position them so that (for example) up is "On", and down is "Off"
That's how I've done mine, except they are labeled for visitors.
Ah, but that would be way too simple. Actually, I am building a control board and the lights would give a stronger visual clue than the switches alone.
Richard
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
Easy way to do it with an LED and resistor, nothing else - you want a "bicolor 2 lead LED". Looks just like an ordinary LED< but inside it are two LEDs, usually a green adn a red, wired back to back. Use a 1K resistor. This will be exactly like the track status light in the Zephyr. It will be a reddish-orange color unless you use address 00 to run a DC loco, in which case it would turn either more green or more red depending on which direction, again just like the LED in the Zephyr itself. This conveniently gives you the protection of the reversed diode without having to hook up or even know what such a thing is.
Just remember, LED's are current operated, not voltage operated like light bulbs. That does confuse some.
I never have to use math for this. Too many in series and they will be very dim. Then you just need a little more voltage.
The most I have ever used are three in series with the same resistor. Maybe four would be ok but never tried.
cacole . . .but if you don't know any more than how to plug in and turn on a lamp you need more help that can be provided on a forum of this type.
. . .but if you don't know any more than how to plug in and turn on a lamp you need more help that can be provided on a forum of this type.
Okay, the lamp comment may have been a bit of an exaggeration. I did take (and pass) a couple of semesters of Physics in college, but that was a long, long time ago, and I have had no reason to use the electrical concepts until now. Rich’s pointer may be the ticket. (Thank you.) I will need to nosh on it for a while, blow the cobwebs off of some old brain cells, and see what happens.
I think I am going to be in the market for a refresher electronics book soon.
Edit: And done. I just ordered a copy of "Getting Started in Electronics," by Forrest Mims. Thank you Amazon Prime.
A straight LED without a resistor (1,000 Ohms) would go 'poof' and instantly burn out as soon as power is applied.
The most basic circuit would be to connect a resistor to one leg of the LED and then wire them across the rails.
A more complex circuit involves a bridge rectifier to provide smoother DC voltage to the LED instead of the high frequency pulsing that a resistor alone would apply, but if you don't know any more than how to plug in and turn on a lamp you need more help that can be provided on a forum of this type.
Scroll down a little ways to Using an LED to Indicate DCC Track Power On
Many use a 1K, 1/4 watt resistor. I use 1K with most decoders and track indication.
560 ohms will result in a little brighter LED. Most LED's are 20 ma max.
http://www.wiringfordcc.com/gorhlite.htm
Look at the below site for more LED info. He mentions a capacitor but I have never seen anyone do this. The site has loads of good DCC info.
http://www.mrdccu.com/curriculum/lighting/LED.htm
The DCC does not cause pulsing to the LED, at least never for me.
My NCE Power Cab DCC controller has a 3mm red led and 1K resistor in the control panel that monitors the DCC. No diode. Still working for some years.
Below is another site you might like on this issue.
http://www.members.optusnet.com.au/nswmn1/Lights_in_DCC.htm
Let me begin by saying my experience with things electrical is I know how to plug in a lamp and turn it on. (Okay, maybe a little more than that, but not much.) I would like to place some indicator lights on my layout to show whether or not a given isolated segment of track is getting power (Zephyr DCC). They are branches in my switching yard that I want to "turn off" if there is a DC locomotive parked on the rails. I went looking for, and found LEDs, but I have no idea which ones to use and what I need to do to use them. Thanks in advance for your sage advice.