I'm ready to install LEDs on the facia and would like to know how you bond the wire to the stiff wire of the LEDs before soldering. My thought is to twist the wire around the lead and then solder. or bend the lead to a U shape. and squeeze them together with pliars.
It must be simple but to me it is difficult to figue out.
Help appreciated. A few more steps and I'll have the switch machines installed.
Thanks,
Bob
Don't Ever Give Up
For the wiring behind a fascia, twisting the end of the wire around the LED lead a couple of times is okay. A heat sink of some type should be clipped onto the LED lead between the base of the LED and the solder joint.
For locomotive lighting, I cut the LED lead and bend a small loop into it, insert the wire or resistor lead, and crimp. A heat sink here is advisable, too.
LEDs can easily be damaged and made worthless if you apply too much heat to them.
Tin the wire, tin the lead on the led. Now touch the tinned wire to the lead on the led. Heat with a soldering iron until they flow. Remove the iron and cool.
With your advice the soldering went well but no light. I'm using the DC side of a transformer in order to control the current.
Is that the problem?
You probably have the polarity backwards -- LEDs are definitely polarity sensitive and if you connect them backwards, they won't light.
I'm not sure what you mean when you say you're using the DC side of a transformer to control the current. If you mean the speed control on a power pack, that is controlling only the output voltage, not current. A resistor must be added to the circuit to limit the current; usually something in the range of 1KOhm.
If you are using the power pack's DC output, flip the direction toggle switch and try again, but not without a resistor in the circuit or the LED is likely to just make a bright flash and be destroyed. You may have already destroyed it if you didn't have the resistor the first time you turned it on.
The lighing problem is related to the transformer. I tried a second and no problem. The first one works intermittenly.
I really appreciate the soldering advice.
It was real simple.
I strip the plastic insulation from the wire, then twist it around the leg of the LED, With a little flux on my fingerm, I rub the flux around the wire that I just twisted on the leg of the LED, then aplly solder. It results in a thin, tight bond. I would never bend the leg of the LED to hold wire, too bulky.
Alton Junction
Not to mention bending the lead of the LED can cuase the hair-thin wire inside to be stressed and break. I you MUST bend the leads of the LED, like I did to replace the orange ones in my Stewart locos with golden-white, use a pair of pliers to hold the LED side and provide a surface to bend against.
For attaching wires, yes, wrap the wire around the lead, not the other way around. Shouldn't need a heat sink, if the solder doesn't flow a second, tops, the tip of your iron is dirty. I cut the leads off fairly short when installing LEDs in locos, and have yet to fry one by overheating it when soldering. Just remember to slip the piece of heat shrink on the wire BEFORE soldering, if you're going to use it for insulation.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I have a pair of cross locking tweezers with a pointed end at about a 1/32 inch tip at a 45 degree angle. I use them as a heat sink and .015 solder. My little 15 watt soldering iron and tinned wire. I never had a problem soldering right up tight against the LED. It only takes a tiny amount of solder for a good strong connection. Once they are soldered on I trim the LEDs leads as short as possible. That way after heat shrinking the ends it fits nicely in a head light casting on my steamers. Some I have filed and polished the end of the LED as flat as possible. You can only flatten the end of the LED so far without ruining it.
Pete
I pray every day I break even, Cause I can really use the money!
I started with nothing and still have most of it left!
If you hold the LED up to the light, you can usually (might need a magnifier) see the hair-fine wire that goes from the smaller terminal into the top of the larger one inside (the point of contact of this wire with the substrate on the larger piece of metal is the actual diode junction). You can file down to just above this wire. Disturb the wire, or either of the two legs, such that the wire moves even slightly, and the junction is broken and so's the LED.
Don't forget a dropping resistor if the voltage is over the rating of the LED's. Otherwise their life will be very short, sometimes a few seconds.
Springfield PA
You have given me a lot of good information.
I do have a "gizmo" that has two alligator clips to hold the wire while soldering. I opened a can of liquid electrical tape and the fumes about knocked me down. My wife is highly allergic and sensitive so one of the rules is that I don't bring or use that kind of stuff in the house and I respect her problem. The heat shrink tape hopefully will take care of that.
I'm saving this thread for future use. Never heard of filing LEDs.
Thanks every one.
superbeYou have given me a lot of good information. I do have a "gizmo" that has two alligator clips to hold the wire while soldering. I opened a can of liquid electrical tape and the fumes about knocked me down. My wife is highly allergic and sensitive so one of the rules is that I don't bring or use that kind of stuff in the house and I respect her problem. The heat shrink tape hopefully will take care of that. I'm saving this thread for future use. Never heard of filing LEDs. Thanks every one. Bob
Bob,
Use that gizmo with the clips for sure. A "Third Hand" or "Helping Hands" vise is perfect for this sort of thing. It's a clamp and a heat sink in one if you can position things correctly.
Just to clarify, Heat shrink is a tube that slips over the wire. Once the connection is made the tubing is slid down over the bare portion and heated to make it shrink to tightly "wrap" the wire.
Another option, though not as good, is Kapton Tape. Kapton tape is heat resistant tape. It is often used to insulate connections in loco's etc. where heat is present from the motor. Unlike regular electrical tape Kapton tapes adhesive will not soften and become gooey from the heat of the motor in an enclosed space.
The local Radio Shack has the shrink tubing so that's what I'll use.
Incidently I needed spade connectors for 24 gauge wire and had to order them on line from RS. They are actually described as Telphone Spade Lugs. The postage was going to be way more that the cost of the connectors but I lucked out. They have a free postage program for any order through April 22nd.
This morning I saw a FedEx truck in the neighborhood and I checked the delivery status and it said delivered. I made a bee line for the front door and there they were so it's back under the layout. Ouch!!
Thanks for the tips.