This is probably a dumb question, but I cant find it in my documentation for the decoder. My decoder has a common wire for all lights, with four seperate light functions (head, tail and two accessory). Does the resistor go on the common, or on the seperate wire for each light?
resistors for lights
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Speaking about resistance only there is no polarity in resistors. if only one resistor was provided and there are multiple light then I would assume, I think it would be safe to assume, that the resistor goes on the common.
But this is strictly speaking basic electronics. not decoder specific.
I have no actual experience with decoders. I strictly run a DC analog railroad. though I'm warming up to the idea of DCC.
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I concede.
Thanks. They aren't working the other way around, so I guess that's a safe assumption
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Do the lights you have-in-hand have resistors pre-wired into them?
Although it seems backwards, for dcc the "positive" wire is the common wire (what I'd think of as the ground), and the "negative" wire is the switched wire.
I've found one can just "experiment" to discover what works:
Put the engine on dcc powered track.
Turn the headlights on using your dcc controller (even though they're not yet connected to the dcc decoder).
Locate where the leads connect.
Try the light "one way", and if it doesn't light, try it the other way.
Make a note on paper so you won't forget (like I would).
I get pre-wired LEDs with resistors on ebay. 1.8 or 1.9mm sizes. See this link:
On these, the red wire is positive (the common wire), and the black wire is negative (the "Switched" wire).
Although it seems backwards, for dcc the "positive" wire is the common wire (what I'd think of as the ground), and the "negative" wire is the switched wire.
I've found one can just "experiment" to discover what works:
Put the engine on dcc powered track.
Turn the headlights on using your dcc controller (even though they're not yet connected to the dcc decoder).
Locate where the leads connect.
Try the light "one way", and if it doesn't light, try it the other way.
Make a note on paper so you won't forget (like I would).
I get pre-wired LEDs with resistors on ebay. 1.8 or 1.9mm sizes. See this link:
led 1.9mm warm white pre wired for sale | eBay
Get the best deals for led 1.9mm warm white pre wired at eBay.com. We have a great online selection at the lowest prices with Fast & Free shipping on many items!
www.ebay.com
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Each light should have its own resistor, otherwise the brightness will change as various lights are turned on or off. Makes no difference on which lead the resistor is on as long as it only goes to one LED. The reason the decoder has a common + and individual controlled grounds is that its an easier and safer circuit to use, called "open Collector".
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