Re: TI-H: NS Illuminator
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Re: TI-H: NS Illuminator
Can I have the web page for teh NS illuminator?
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> From: Jonathan Anderson <sarlok@geocities.com>
> To: ti-hardware@lists.ticalc.org
> Subject: Re: TI-H: NS Illuminator
> Date: Thu, 09 Oct 1997 20:46:07 -0700
>
> Here's a small explanation of resistance and voltage in series circuits:
> (assuming I remember last year's physics correctly)
>
> First, let's pretend we have a 4V circuit with two 1 ohm resistors.
> Each resistor would eat up 2V. If you had a 3 ohm resistor and a 1 ohm
> resistor, the 3 ohm would use 3V and the 1 ohm 1V. So, the voltage used
> by each load is the load's fraction of the total resistance; i.e.
> Vload=V*Rload/(Rload+Rload2+Rload3+...).
>
> Well, find out the resistance of your LED (I'll call it R) and then
> multiply it by 3V (total voltage) and divide it by 2.4V (voltage for the
> LED). Take that quotient and subtract the resistance of your LED, and
> you have the resistance of the resistor that you need. Example, if your
> LED used 4 ohms, you take (4*3/2.4)-4=1 ohm and you use a 1 ohm
> resistor.
>
> Even if the diode works, a resistor has a couple advantages. First, a
> constant .6V drop yields too little voltage if your batteries drop below
> 1.35V each. With resistors, when the batteries lose voltage, the
> resistor takes less voltage too, so your batteries can drop to 1.31V
> before the LED gets less power than it needs.
>
> NDStein@aol.com wrote:
> >
> > I know a resistor is better and more efficient. However, this is as far
as
> > I've gone so far. I don't know how to calculate the resistance I need,
as I
> > thought you need to know amperage to calculate the resistance you should
> > have. I don't know the amperage of 2 AA batteries, and I assumed it
varied.
> > Maybe you can explain this to me in #ticalc some day. Also, I thought
> > silicon diodes (normal ones, not the rectifier diodes, etc.) always gave
a .6
> > v drop. This is what I read in the radio shack electronics book ;-).
In
> > this case, what kind of drop would you expect, and why would I burn
something
> > out? However, I was planning on substituting a resistor when I found
out
> > what to use.
> >
> > -Noah
>
> --
> Jonathan Anderson
> sarlok@geocities.com
>
> "I can't be wrong - my modem is error correcting."
>