Re: TI-H: EL Backlight installed!

To: ti-hardware@lists.ticalc.org
Subject: Re: TI-H: EL Backlight installed!
From: Greg Hill <gregh@xmission.com>
Date: Tue, 14 Apr 1998 22:51:19 -0700 (PDT)
Delivered-To: ti-hardware-outgoing@towerguard.unix.edu.sollentuna.se
In-Reply-To: <35342F1B.4A7D73A8@ff.lakeheadu.ca>
Reply-To: ti-hardware@lists.ticalc.org

On Tue, 14 Apr 1998, Chris Cooper wrote:

> > The LCD requires AC to run, correct?  Where is the AC power for the
> > LCD produced?  (I don't have schematics).
> 
> Is this correct? if so, wouldn't it be possible to do away with the
> Inverter?  Since the EL is supposedly able to handle anything up 120VAC?
> (240?)

If I have my facts straight, an LCD panel does use AC voltage to produce
an output. For a more detailed description, look on Sharp's web site or
someplace where they make LCD panels.. Anyway, there are a bunch of
regions (pixels) which can be clear or dark. They get made clear by
putting a voltage of one polarity on, and they get made dark by putting
the opposite polarity on. The voltage determines how dark the pixel is.

So LCD panels do use AC, but it is a very small (millivolt?) voltage... 
not nearly enough for an EL panel. 

Most EL panels are designed with 120 v ac in mind because that is most
common in the US. They draw a couple milliamps at that voltage. So an EL
panel can be powered directly from a wall socket, or it can be powered
from a battery with the help of an inverter, which makes a high ac voltage
from a much lower dc voltage. 

-- 
Greg Hill
greg-hill@bigfoot.com
www.comports.com/link

References:

Re: TI-H: EL Backlight installed!

From: Chris Cooper <cooper@fort-frances.LakeheadU.Ca>