Using LEDs to light model train layouts
ND
incandescent lighting":
DMS
the best, they are even smaller than the 3mm ones and they emit light
in a broad angle...
How I convert station lamps: http://layout.mixmox.com/1/Marklin-7283
Resistor values for 12V: http://layout.mixmox.com/1/Resistors
Determining resistance values: http://layout.mixmox.com/1/LED-resistor
Results
Illuminated signal box: http://layout.mixmox.com/1/signal_box
In a winery building: http://layout.mixmox.com/1/Faller-130904
As an arc-welder: http://layout.mixmox.com/1/Man-welding
Shed light: http://layout.mixmox.com/1/shed-light
Tunnel signal: http://layout.mixmox.com/1/tunnel-signal
Water crane lantern: http://layout.mixmox.com/1/Water-crane-lamp
Yup, I just love LEDs !
and BTW, don't waste money on expensive ones of certain color, just
use a dab of acrylic paint to make them as warm as you want them to
be. Takes a just a few seconds.
Dale
http://remotesign.mixmox.com
Dan Merkel
news:5806c26b-2826-48d7...@p25g2000hsf.googlegroups.com...
Dale
http://remotesign.mixmox.com
For those of us who are complete novices at LEDs & electronics in general,
can you provide some information as to how one would wire a circuit to use
them? I seem to remember that LEDs have a polarity to them (which is
which), how about resistors? This looks interesting but I'm at a total loss
when it comes to even simple things mentioned in the previous two posts.
Thanks...
dlm
Greg Procter
Most LEDs output only a very limited part of the colour spectrum, so
filtering them with a dab of acrylic paint can only reduce the spectrum
further, not change the colour.
"White" LEDs have (I think) phosphor over the light output which is
activated by the energy output and gives a much broader spectrum light
output, so you can filter those with the 'dab of acrylic' method.
The long lead is the positive one.
DMS
some chemical trickery.
starting with white LEDs and adding acrylic paint I am able to produce
lights that range from fluorescent looking to incandescent looking -
as you can see in my photographs of the results. (and they do look
better in real life than the photographs)
gagno...@netscape.net
wka...@mtholyoke.edu
> For those of us who are complete novices at LEDs & electronics in general,
> can you provide some information as to how one would wire a circuit to use
> them? I seem to remember that LEDs have a polarity to them (which is
> which), how about resistors? This looks interesting but I'm at a total loss
> when it comes to even simple things mentioned in the previous two posts.
I can never remember which lead is + or -. I connect the LED to a 1.5V
source. If it lights, I have it right. If it doesn't I reverse the
leads. If it doesn't light then, it's no good.
Connecting the LED to a low voltage source like that won't harm it if it's
backwards. It's a diode, after all.
--
Bill Kaiser
wka...@mtholyoke.edu
There are three ways to do a job: good, cheap, and quick.
You can have any two.
A good, cheap job won't be quick.
A good, quick job won't be cheap.
A cheap, quick job won't be good.
David Nebenzahl
> Dan Merkel <danm...@sbcglobal.net> wrote:
>
>> For those of us who are complete novices at LEDs & electronics in general,
>> can you provide some information as to how one would wire a circuit to use
>> them? I seem to remember that LEDs have a polarity to them (which is
>> which), how about resistors? This looks interesting but I'm at a total loss
>> when it comes to even simple things mentioned in the previous two posts.
>
> I can never remember which lead is + or -. I connect the LED to a 1.5V
> source. If it lights, I have it right. If it doesn't I reverse the
> leads. If it doesn't light then, it's no good.
>
> Connecting the LED to a low voltage source like that won't harm it if it's
> backwards. It's a diode, after all.
Yep, true that.
In fact, if one is handling a lot of LEDs and wants to identify polarity
quickly, one could build a little testing rig out of a 1.5 volt battery
holder and a couple of wires (color-coded) connected to alligator clips.
--
The best argument against democracy is a five-minute
conversation with the average voter.
- Attributed to Winston Churchill
Rick Jones
>
> I can never remember which lead is + or -. I connect the LED to a 1.5V
> source. If it lights, I have it right. If it doesn't I reverse the
> leads. If it doesn't light then, it's no good.
I recommend that everyone that is building a layout have a
multimeter. The usefulness of one of these for electrical work and
troubleshooting can't be ignored. You can get a rudimentary one in the
$20-30 that will probably have all of the functions you'll need for most
hobbyist work, including a diode check function.
The easy way to visually identify anode and cathode on a normal LED
is to hold it sideways. If you look through the lens the cathode is
normally the lead attached to the little "cup" in the center, and the
anode is attached to the wire that comes out of the "cup" to the other
lead. Anode is + and cathode is -. SMD or other packaged LEDs are harder
to determine without a meter with a diode check, though many will have
some type of marking that a manufacturer's data sheet will help you
identify. A good source of data sheets if you know the part number of an
electronic component is www.alldatasheet.com. I use it nearly every day
at work trying to find information on components in equipment I'm repairing.
--
Rick Jones
Remove the Extra Dot to e-mail me
"Traditionally, most of Australia's imports come from overseas."
-Keppel Enderbery
MangroveRoot
> In fact, if one is handling a lot of LEDs and wants to identify polarity
> quickly, one could build a little testing rig out of a 1.5 volt battery
> holder and a couple of wires (color-coded) connected to alligator clips.
(Yes, this is months later, I'm catching up, oh well.)
I can envision getting (or having on hand)
one of those little white(ish) "experimenter's block" things from Rat Shack,
generally intended for putting ICs down the middle and ancillary components
next to their leads.
They are particularly adapted to just shoving component leads into them
and then yanking them out again (okay, pushing and pulling them carefully),
without requiring clips or clamps etc.
HOWEVER, if I understand what I have read here correctly,
the presence of all those nifty little holes for the leads from the LEDs
(haha) should not be taken as an invitation to test them all at once.
If someone can explain how to do that after all, that would be a plus.
(Ouch, sorry.)
David Nebenzahl
> David Nebenzahl wrote:
>
>> In fact, if one is handling a lot of LEDs and wants to identify polarity
>> quickly, one could build a little testing rig out of a 1.5 volt battery
>> holder and a couple of wires (color-coded) connected to alligator clips.
>
> (Yes, this is months later, I'm catching up, oh well.)
>
> I can envision getting (or having on hand) one of those little
> white(ish) "experimenter's block" things from Rat Shack, generally
> intended for putting ICs down the middle and ancillary omponents next
> to their leads.
Yes; they're called "experimenter's boards", "prototyping boards",
"breadboards", etc. (People used to use real breadboards back in the
day, hence the name.) Very handy little things they are. Don't go to
Radio Shack; go to a *real* electronics store (if you're lucky enough to
have one nearby). RS is a ripoff.
> They are particularly adapted to just shoving component leads into them
> and then yanking them out again (okay, pushing and pulling them carefully),
> without requiring clips or clamps etc.
>
> HOWEVER, if I understand what I have read here correctly,
> the presence of all those nifty little holes for the leads from the LEDs
> (haha) should not be taken as an invitation to test them all at once.
You could test a bunch at once just by connecting them in parallel, so
long as you have a current-limiting resistor in series with the bunch.
Probably easier just to test them one at a time, unless you have dozens
to go through, since if you don't know what polarity they are, they
could either be bad or connected backwards. (I don't know the rules for
identifying LED polarity; maybe someone else here does.)
--
Washing one's hands of the conflict between the powerful and the
powerless means to side with the powerful, not to be neutral.
- Paulo Freire
Lloyd Olson
"David Nebenzahl" <nob...@but.us.chickens> wrote in message
news:496a9be7$0$12880$8226...@news.adtechcomputers.com...
(I don't know the rules for identifying LED polarity; maybe someone else
here does.)
>
Look at the LED from the side. One wire leads to the base of the
substrate which emits the light, the other is connected to a very fine
wire leading to the top of the substrate. The one leading to the base is
the cathode (-), the other is the anode (+). LTG :)
Peter W.
>
>
> Look at the LED from the side. One wire leads to the base of the
> substrate which emits the light, the other is connected to a very fine
> wire leading to the top of the substrate. The one leading to the base is
> the cathode (-), the other is the anode (+). LTG :)
Not always - some have reversed layout. Not very common but they do
exist.
If the LEDs are new then another possible clue is the length of its
leads - longer is positive. Sometimes the collar on the bottom of the
LED case has a flat spot on it near one lead - that is usually
negative.
I made a very simple LED tested which I have been using for years:
Take an old 9V battery apart and save the top cover which has the
contacts on it. Take a small piece of copper-clad PC board (about
3/8" x 3/8") and cut the copper across the center (dividing it into 2
isolated copper areas). Solder one side of the copper board to one of
the battery contacts on the back of the battery cover. Solder a 1/4 or
1/8W 1k ohm resistor, one end to the other copper area and the other
end to the other battery contact. Snap your "LED tester" assembly
onto a new 9V battery. To test an LED just place each of its legs on
each of the copper areas of the PC board. If it doesn't light up,
reverse the LED
Peteski
Twibil
> I made a very simple LED tester which I have been using for years:
> Take an old 9V battery apart and save the top cover which has the
> contacts on it. Take a small piece of copper-clad PC board (about
> 3/8" x 3/8") and cut the copper across the center (dividing it into 2
> isolated copper areas). Solder one side of the copper board to one of
> the battery contacts on the back of the battery cover. Solder a 1/4 or
> 1/8W 1k ohm resistor, one end to the other copper area and the other
> end to the other battery contact. Snap your "LED tester" assembly
> onto a new 9V battery. To test an LED just place each of its legs on
> each of the copper areas of the PC board. If it doesn't light up,
> reverse the LED
What a good idea!
Thanx!
~Pete
David Nebenzahl
Hey, here's an even better idea (inspiration from the Pete 2 messages
back): take that 9-volt battery top and solder a wire to each connector.
Solder a small alligator clip to each wire, with that 1K resistor in
series with one of them. Voila! A handy-dandy LED tester that grabs the
leads of the "device under test".
--
In order to embark on a new course, the only one that will
solve the problem: negotiations and peace with the Palestinians,
the Lebanese, the Syrians. And: with Hamas and Hizbullah.
Because it's only with enemies that one makes peace.
- Uri Avnery, Israeli writer and peace activist with Gush Shalom.
(http://counterpunch.org/avnery08032006.html)
Steve Caple
> Solder a 1/4 or 1/8W 1k ohm resistor, one end to the other copper area
> and the other end to the other battery contact. Snap your "LED tester"
> assembly onto a new 9V battery. To test an LED just place each of its
> legs on each of the copper areas of the PC board. If it doesn't light
> up, reverse the LED
And then mark the positive lead with a spot of paint.
--
Steve
Bob May
batteries connecto together. Just put a resistor in one lead and put a 1
pin connector on the end of the wires and plug in a LED and see which way it
lights. I would use a 470 ohm resistor which will keep the current below
the max. 20mA that most LEDs are rated for.
LEDs are always marked with either/both a flat or notch in one side and a
longer lead to indicate to the assembler which way to put in the LED.
--
Bob May
rmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net
Bob May
all connected. On ones with more than one set of slots, the narrow slots
are where the gap[ is and there is no connection to the other parts of the
board.
You don't want to put the LEDs in parallel as they will all tend to have
different brightess levels as the lower voltage ones will draw more current
and the h9gher voltage ones will draw less current. Putting a number o9f
LEDs in series will work if you have a somewhat constant current source as
it is more the current that generates the light rather than the voltage.
You will find tho that it will be easier to just put one LED in and then see
if that works due to the assembly time it takes to put in several LEDs to
see if they work.
Additional problems with putting several LEDs in parallel for a testing
envoriment means that you have to disconnect the power or you will pop the
LED as you put it in the tester as it will be overcurrented and will
overheat, destro9ying the LED. LEDs can take more than 20mA but only for
very short periods with long rests inbetween to keep the heat down. Arrays
of LEDs are often scanned to minimize the necessary electronics driving
them.
Peter W.
> To make things simpler than taking apart a battery, the connector for 9V
> batteries connecto together. Just put a resistor in one lead and put a 1
> pin connector on the end of the wires and plug in a LED and see which way it
> lights. I would use a 470 ohm resistor which will keep the current below
> the max. 20mA that most LEDs are rated for.
> LEDs are always marked with either/both a flat or notch in one side and a
> longer lead to indicate to the assembler which way to put in the LED.
>
> --
> Bob May
I was keeping my tester design as simple, cheap and compact as
possible. 1k ohm resistor is even safer than 470 ohm and the LEDs
still light up.
Peteski