Subject:
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Re: Station lighting
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Newsgroups:
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lugnet.org.ca.rtltoronto
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Date:
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Fri, 30 Aug 2002 10:26:47 GMT
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Viewed:
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995 times
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In lugnet.org.ca.rtltoronto, Jeff Elliott writes:
> Hi folks,
>
> I've got an electronics-ish question to ask:
>
> I'm building that 2-level station I was talking about before. Looks
> nice, IMHO. But there's going to be a problem when I'm done: the
> back area of the lower level is simply going to be too dark. I'd
> like to light it, but Lego wheat bulb lights are pathetically dim.
>
> So I'm thinking of buying a bunch of high-intensity white or light
> blue LEDs from one of those Queen St. electronics operations. The
> idea would be to wire them to a battery pack, or ideally a regulator
> (to save on batteries). Then I can tuck them up out of sight in the
> ceiling, and the back platform will be nicely lit.
>
> Now how do I go about figuring out how to wire them? Series?
> Parallel? How many can / should I put on a single 9v pack? Or
> should I forgo Lego entirely and use a 4.5v pack? What stats
> do I need to know about the LEDs before I make these decisions?
> Do I need to throw a resistor into the mix?
>
> Jeff E
Hi Jeff, to answer the question with exact detail, I would need to know who
many LED you want to put, and what is the typical voltage drop and current of
the LEDs.
typicaly put them in serie with a resistor.
---|>---|>----|>---/\/\/\----
LED LED LED resistor
here is a bit of theorie.
each led will do a fix drop in voltage (in the range of 1.5 to 2V for green,
red and amber). let supposed that your led have a 2.0 volt drop, if you put 4
in serie, that will be 8.0 volt total. you will need a supplyed voltage of over
8 volt if not the LED will not lite as they won't have enough power.
you also have to limit the current in those LED, here come the resistor. If you
that the 4 LED from previous paragraph with a 9.0 volt supply (regulator) and
again we suppose the those LED need a 10 mA current, we will need a resistor
that will let 10mA pass with a 1.0V (9.0-8.0) in it.
R = U/I so you will need 1.0V/10mA = 100 ohm resistor.
again those number are just for explanation, I don't have the spec of those
white LED, if you get them, I'll be able to help you figure out what resistor
value you'll need.
Martin
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Message is in Reply To:
 | | Station lighting
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| Hi folks, I've got an electronics-ish question to ask: I'm building that 2-level station I was talking about before. Looks nice, IMHO. But there's going to be a problem when I'm done: the back area of the lower level is simply going to be too dark. (...) (22 years ago, 29-Aug-02, to lugnet.org.ca.rtltoronto)
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