LEDs and operation.
Tom
wrote August 27, 2005 Subject: [NCE-DCC] LED's
I am
trying to install LED's for the first time and I find they don't work. So far I
have attempted to put them on a Proto 1000 Budd Car and F-3. Original lights
work fine, but the LED's don't. I haven't come across any how to instructions
and I'm wondering if I'm doing something wrong.
Chris
replied
Yes,
and No.
If
you've wired in the resistor as required and you've wired it in so the polarity
is correct, the LEDs will work just fine without any
further configuring.
HOWEVER,
LEDs are current driven and not voltage driven like
light bulbs and motors. Light bulbs will
get brighter as the voltage goes up since the current draw goes up at the same
time. More voltage,
more current, more heat. You'll
also notice that it takes a little bit of time for bulbs to hit full brightness
and dim to off when you cut the power, afterglow if you will. LEDs like to suck
as much current as they're rated for once you hit a certain voltage point,
which means it's really hard to control them with voltage which makes it tough
to use them on analog DC. They're pretty
much instant on/off devices.
DCC
does lighting effects by controlling how often you have an output
"ON". Pulse it on/off really
fast and you can make it look brighter or dimmer depending on how many pulses
you use for the ON time.
What
setting the CVs to LED mode does is take into account
the instant on/off of LEDs and uses a different
"curve" for the lighting output in the decoder. You may notice this if you have an Atlas decoder
with LED headlights. They tend to have a
definite strobing/flicker in them since the decoder
doesn't "know" how to deal with them.
With an LED aware decoder there's a lot more ON pulses used in the
timing so your ditch lights now flash on and off with a definite brightening
and dimming instead of instant blinking on/off that you might get
otherwise.
They'll
work without setting it, but it won't really look right. Of course, for a strobe as a roof beacon LEDs are hard to beat for the "pop" effect.
-
Chris
---
In
>
Don't LED's need to be configured to work properly with NCE decoders?
> ----- Original Message -----
> From: tom7502
> To:
> Sent: Saturday, August 27, 2005 2:43 PM
> Subject: [NCE-DCC] LED's
>
>
> I am trying to install LED's for the first
time and I find they don't work. So far I have attempted to put them on a Proto
1000 Budd Car and F-3. Original lights work fine, but the LED's don't. I
haven't come across any how to instructions and I'm wondering if I'm doing something
wrong.
Tom Laware