Re: TI-H: AC adaptor

To: ti-hardware@lists.ticalc.org
Subject: Re: TI-H: AC adaptor
From: tsaimelv@pilot.msu.edu (Mel Tsai)
Date: Sun, 15 Dec 1996 20:24:45 GMT
In-Reply-To: <TCPSMTP.16.12.14.-10.31.58.2508442838.3139129@bbs.gaianet.net>
References: <TCPSMTP.16.12.14.-10.31.58.2508442838.3139129@bbs.gaianet.net>
Reply-To: ti-hardware@lists.ticalc.org

On Sat, 14 Dec 1996 22:31:58 -0500 , you wrote:
>TI>I'm trying to build an AC adaptor for my 85.  I have an adaptor that outputs
>TI>6V DC (which is what the 6 AAA batts output) but it outputs that at (I think
>TI>300mA.  How do I reduce that to the level that the calc needs?  I've tried
>TI>hooking it to my calc by connecting the leads directly to the battery
>TI>terminals.  It will turn on and not lose the memory, but the screen is
>TI>totally "lit up".  Even at the lowest contrast level, you can't see anything
>TI> I need to put in something to reduce the amps, but I'm not sure what.
>
>       If it's a multi-adapter, set it to 4.5 volts.. that's how I use
>mine..

That's how it should be done...  The calculator is designed to use 4
1.5V batteries, but most of the time the AAA's won't be the full 1.5V
so the "maximum" voltage should be around 6v, with optimum voltages
around 4.5-5V.  With the voltage around 6V, the resistance is still
the same so it's drawing a lot more current than it normally should
(the current rating on the AC adaptor, by the way, should have almost
no effect on the calculator, i.e. it's pretty much irrelevant).

-Mel

--
The TI Memory Expansion Homepage
http://pilot.msu.edu/user/tsaimelv/expander.htm

References:

TI-H: AC adaptor

From: zarquon@gaianet.net