I’m giving up on the LED…
I want to put a light bulb in my decoderized S1.
It’s a 12 v Gor bulb --50 ma.
I have a 240 ohm and a 1K. Which should I use? Or do I even need one?
SOL-VED see below.
Chip-
You shouldn’t need any. It is a 12V bulb with a 12V source. The reason an LED needs a resistor is that it does not want to see 12V, so the rest of the voltage needs to be dropped over the resistor. The LED drops in the neighborhood of 2V, so the resistor is needed to drop the rest. The value of the resistor is chosen to limit the current to no more than the LED wants to see.
Good luck.
Jeff
Good answer, Jeff. One thought in addition however; you may still want to use the 240 ohn resistor to entend the life of the bulb and reduce the heat it produces since under DCC it will be lit when ever it is on the layout. I also had another thought about the LED problem itself, there could be a mechanical fault in the LED or the lead conection from the decoder itself, that is "cured when fat fingers, probe or what ever other outside intervention happens to close the open mechanical gap. If the fault is a cold solder joint on the decoder board, you could still have the same problem with the lamp. Hope this throws a little light on the things that drive all of us crazy!!!
Will
I was thinking about a failure of the connection in the LED, in the decoder would make sense too. If it is the decoder, it might be fixable.
Chip,
As the others have said, in the case of a 12-volt bulb, resistance is futile.
[:o)] [8] [:O] [
] [sigh]
Decoder manufacturers recommend a 22 Ohm resistor to limit the initial current inrush when a bulb is turned on, to protect the decoder, but since decoder output is 12 volts the resistor is only for current limiting purposes.
You will be assemilated into the Borg collective!!! MWAHAHAHA!!!
If it’s a 12 volt maximum voltage bulb then you’ll want to make sure your power pack doesn’t go over 12 volts. Otherwise, POW!!! No more bulb.
Got alligator clip leads? A set of 5, all different colors, is only a few bucks, and is a great investment. My green one is hooked up to something, but I can’t find it. Or was the green one a real alligator?
I like to test every light, LED or incandescent, before I put it someplace where the sun don’t shine, like in my subway tunnels. If you’re running a 12-volt incandescent lamp on a 12-volt source, you should be fine, but how bright will it be? If you put in a 240-ohm resistor, then how bright is it? What you’ve got to decide is how bright do YOU want the bulb. More resistance means longer bulb life, but also a dimmer headlight. The replacement cost won’t matter much, but how bad is the replacement job?
LEDs are either on or off, and the idea is to use the biggest resistor to prolong their life, which may already be longer than yours, anyway. For a LED, try a 1K first, and if it doesn’t work go down to a 480-ohm. Remember to test your L:EDs on DC. Incandescents don’t care.
The case is sol-ved. I think it is the decoder. With the light bulb, DC powers it through every joint back to and including the socket. Put the decoder in, nothing. Since it was the same as the LED, the only thing left to fail is the decoder.
Sol-ved, but not to my satisfaction and two evenings wasted. (I could have built my 0-6-0s[|(])
Riddle me this…
How many Space Mice does it take to change a light bulb?
Don’t know…It’s never been done.
It could be where the wire attaches to the decoder, in which case you might be able to make a repair with a little touch of a soldering iron, and some heat shrink tubing of something to get it all insulated again (I am assuming a wired in decoder).
It is a plug in. The socket is fine. My theory is that the prong from the decoder is not making solid contact.
These dang new fangled electronic things getting in the way of the “important” (or is that impotent) stuff like building engines, laying track, or one draw at the “honey do” jar.
Sorry to hear that it was one of those problems that we can’t control, but look on the bright side it wasn’t foam punching a hole in the wing, and your sanity is now back intact!
Will
Chip, during your short (get it?) tenure of 7 months in the MRR hobby, you have encountered so many problems from the routine to the obscure. It seems that even the most basic task has a Spacemouse effect that extends its completion by several hours and a book full of e-mails. In the past there was a thread of “useful topics”. A compilation of problems encountered by Spacemouse and the solutions to said problems, would be an exceptionally useful guide to beginners in the hobby. Most of all, the tenacity shown to get a problem solved is a lesson to anyone that gets frustrated by the vagaires of some nuance with the hobby.
Hey!! Stop picking on the “Mouse”, remember Thomas Edison had a trial or two on the way to the “lamp” or is that “lightbulb” or the more correct term “Dark Sucker”.
Will
Rule of thumb–
Experience is that thing you get right after you need it.
Three-----1 to hold the bulb and 2 to turn the train…
There is only one difference between an amatuer, and a pro. The pro has already made the mistakes. Space Mouse, just look at it this way. You are already well on the way to pro status![:D][swg]
Did the original light bulb blow out? If so, it probably blew the function output at the same time.
–Randy
Nope, I broke it trying to get it back into the itty-bitty slot. Wasn’t attatched to the decoder then.